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ANNALS OF CARNEGIE MUSEUM 31 December 2008 Vol. 77, Number 3, Pp. 321–402 ON THE CRANIAL OSTEOLOGY OF THE HISPANIOLAN SOLENODON, SOLENODON PARADOXUS BRANDT, 1833 (MAMMALIA, LIPOTYPHLA, SOLENODONTIDAE) John R. Wible Curator, Section of Mammals Carnegie Museum of Natural History, 5800 Baum Boulevard, Pittsburgh, Pennslyvania 15206 [email protected] Abstract The external and internal surfaces of the skull of the Hispaniolan solenodon, Solenodon paradoxus Brandt, 1833, are described and illustrated in detail based on five museum specimens (one from Carnegie Museum of Natural History, the remainder from American Museum of Natural History). Two of the specimens are juveniles that preserve sutural information that is lacking in the adults; one adult is bisected and exposes the interior of the nasal and cranial cavities. A sixth specimen is a serially sectioned ear region of a juvenile from the Max-Planck-Institut für Hirnforschung that provides information on soft-tissue structures. The Hispaniolan solenodon has a peculiar skull with numerous highly unusual features among mammals. Included are: a small, oval ossification, the os proboscidis, jutting anteriorly from the ventral rim of the external nasal aperture; zygoma incomplete and jugal bone absent; exposure of the ethmoid bone in the orbit but palatine not; numerous orbital foramina accommodating veins communicating across the midline ventrally in the presphenoid and dorsally in the frontal; tiny optic foramina; venous transverse canal through basisphenoid; entoglenoid process of squamosal but no postglenoid process; abutment between the rostral process of the malleus and the crista parotica of the petrosal; rostral and caudal tympanic processes of the petrosal fused; large occipital emissary vein foramen endocranially between supraoccipital and parietal; large venous condyloid canal through exoccipital; paired interparietals; mandible with two “angles,” a true angular process and a process for the digastric muscle. Perhaps the most unexpected finding is that of a prootic canal for the lateral head vein in the petrosal bone. Prootic canals are broadly distributed in Mesozoic mammals including a few Cretaceous eutherians, but heretofore are unknown in placentals. Key Words: cranial foramina, Hispaniolan solenodon, osteology, Solenodon paradoxus, skull INTRODUCTION Solenodon paradoxus Brandt, 1833, is a peculiar placental insectivoran from Hispaniola with some well-known cranial oddities. Among others, its submandibular (submaxillary) glands produce toxic saliva (Rabb 1959), and the duct of the gland ends at the base of a deeply grooved lower second incisor (Nowak 1991); its upper molars are zalambdodont, V-shaped in occlusal view with a large central cusp and two buccally extending ridges (Gill 1883; Asher and Sánchez-Villagra 2005); and it has an elongate proboscis (more than 10% of head length) that is supported at its base by a small, round bone, which is absent (Ottenwalder 2001) or “merely represented by somewhat hardened ‘horny’ cartilage” in the other living species, Solenodon cubanus Peters, 1864, from Cuba (Allen 1908:515). Nesophontes Anthony, 1916, is another placental insectivoran (with dilambdodont molars, W-shaped in occlusal view) endemic to the islands of the West Indies that was thought (e.g., MacFadden 1980; Morgan and Woods 1986) to have survived into the 20th century, but has probably been extinct for several hundred years (MacPhee et al. 1999). A long history of phylogenetic hypotheses concerns Solenodon, Nesophontes, the African zalambdodonts (tenrecs and golden moles), and dilambodont insectivorans (shrews and moles) (see summaries in McDowell 1958; Whidden and Asher 2001). Prior to the discovery of Nesophontes (Anthony, 1916), most authors (e.g., Mivart 1871; Dobson 1882–1890; Allen 1910) allied solenodons with African tenrecs, in part because of shared zalambdodonty Wible.indd 321 (Fig. 1). After 1916, authors either continued to support that relationship, including Nesophontes with solenodons and tenrecs (e.g., Allen 1918) or excluding Nesophontes (e.g., Simpson 1945; Van Valen 1967), or allied solenodon and Nesophontes with shrews (e.g., McDowell 1958; McKenna and Bell 1997). Recent DNA sequence analyses have excluded a close relationship between S. paradoxus and tenrecs, linking the former with shrews and moles and the latter with golden moles in Afrosoricida within Afrotheria along with elephant shrews, aardvarks, hyraxes, elephants, and sirenians (Stanhope et al. 1998; Emerson et al. 1999). S. paradoxus grouped with shrew, hedgehog, and mole in a recent study sequencing portions of 16 nuclear and three mitochondrial genes (Roca et al. 2004). The cranial osteology of the solenodon has been the subject of considerable attention, with the most confounding recurring issue being the early fusion of many cranial sutures. The most extensive treatment of the skull in the nineteenth century was the original description of S. paradoxus by Brandt (1833). It includes individual descriptions of most cranial bones in Latin based on a single imperfect skull (lacking the occiput) preserving sutures on the rostrum and skull base in the Zoological Museum in St. Petersburg. The original description of S. cubanus by Peters (1864), based on a single skull in the Museum für Naturkunde in Berlin, noted differences between the two species in some cranial osteological features. Mivart (1868) included some additional observations on the skull of the type of 1/6/09 9:24:22 AM 322 Annals of Carnegie Museum Vol. 77 S. cubanus. For his monograph on insectivorans, Dobson (1882–1890) dissected a solenodon specimen from Paris that had the skin and integumentary muscles removed and made observations on several cranial muscles. The first decade of the twentieth century witnessed four significant contributions to our understanding of solenodon cranial anatomy. Leche (1907) restudied the types of the two species, detailing the milk dentition in S. cubanus and the adult dentition in S. paradoxus and providing more detail on the skulls of both. J.A. Allen (1908) described and photographed the skulls of three S. paradoxus at the American Museum of Natural History in New York and one S. cubanus at the National Museum of Natural History in Washington, D.C. In “The Orders of Mammals”, Gregory (1910) restudied the specimens of S. paradoxus in New York, providing individual descriptions of most cranial bones and foramina and the first line drawings with cranial bones, processes, and foramina labeled (see also Gregory 1920b: fig. 110). These illustrations of a juvenile Hispaniolan solenodon with most cranial sutures represent the most comprehensive for the genus to this day (reproduced here as Fig. 1). For his comprehensive monograph on the anatomy of S. paradoxus, G.M. Allen (1910) studied a series of at least 12 individuals at the Museum of Comparative Zoology in Cambridge; he reported on soft- as well as hard-tissue anatomy including the cranial musculature and brain, although his treatment of cranial osteology is not as extensive as that of Gregory (1910). A more complete description of the solenodon brain is found in Boller (1969). Perhaps the best known contribution on solenodon cranial osteology is McDowell’s (1958) monograph comparing the Greater Antillean insectivorans, Solenodon and Nesophontes. He included detailed, labeled line drawings of the orbit, ear region, squamosal-dentary articulation, and occiput of both forms and an oft-cited glossary on cranial osteology and basicranial vasculature. However, the vast majority of the illustrated specimens of S. paradoxus are adults that lack much sutural information; for example, the orbit illustration does not show a single suture. Another oft-cited monograph with observations on solenodon is MacPhee’s (1981) ontogenetic treatment of the ear region in insectivorans, strepsirhine primates, tree shrews, elephant shrews, and tenrecs. He studied a serially sectioned ear region of a juvenile solenodon and described the hardand soft-tissue auditory anatomy. More recently, Asher (2001) reported on the solenodon vomeronasal organ; Ottenwalder (2001) has revised solenodon systematics at the generic level with a multivariate analysis of largely craniodental measures; and Whidden (2002) dissected muscles of the solenodon snout. In addition to the above works, photographs and drawings of the solenodon skull have been published elsewhere (e.g., Thenius 1989: fig. 143; MacPhee 1994: figs. 6, 8; Starck 1995: fig. 208). However, as plagued most of the classic works on this taxon, the early fusion of cranial sutures constrains the utility of these illustrations. Study of the single solenodon specimen in the Section of Wible.indd 322 Mammals of Carnegie Museum of Natural History as part of a phylogenetic project (Wible et al. 2007, in press) confirmed this early fusion. To facilitate that project, several specimens were borrowed from the American Museum of Natural History, including the juvenile figured by Gregory (1910: fig. 18A1, A2) and McDowell (1958: fig. 1C), a second slightly older juvenile, and a bisected adult skull. These specimens and the dearth of detailed figures that include sutural information of the cranial osteology of this unusual placental are the impetus for the current report. It also represents another contribution in the author’s series on cranial osteology of Recent mammals (see Wible 2003, 2007; Wible and Gaudin 2004; Giannini et al. 2006). Materials and methods The following specimens form the basis for the anatomical descriptions. (1) AMNH 28272 Solenodon paradoxus, Haiti, collected 1907. This juvenile with many open cranial sutures retains some deciduous teeth, which have been described by Allen (1908) and redescribed with corrections by McDowell (1958). Currently, the skull of the specimen is in three principal pieces: right premaxilla, maxilla, lacrimal, and part of the vomer; left premaxilla, maxilla, and part of the vomer; and the braincase and posterior nasal cavity consisting of the ethmoid and part of the vomer. The palatines, middle ear ossicles, and right ectotympanic are missing, and the nasals are represented by the posterior part wedged between the maxillary processes of the frontals and an isolated 21 mm long piece of the right nasal with all but the posterior border preserved intact. The skull was more complete previously, because Allen (1908: pl. 33) published photographs of the whole skull in dorsal, ventral, right lateral, and occipital views; the palatines, right ectotympanic, and nasals are complete in these photographs. However, Allen (1908: pl. 32) also published photographs of the isolated right premaxilla, maxilla, and lacrimal in lateral and ventral views as they are preserved currently. Gregory (1910: fig. 18A1, A2) published line drawings of the whole skull in ventral and left lateral views and addressed aspects of its cranial osteology, including nerve, arterial, and venous foramina (see Fig. 1). Ten year later, Gregory (1920b: fig. 110) published a line drawing of the right snout and orbit in lateral view. McDowell (1958: figs. 1C, 11C, 12B, 14B, 15B, 16B, 18C, 19B) published a line drawing of the whole skull in lateral view and numerous line drawings of the dentition with descriptions and observed that one of the palatines was missing at that time; as noted above, both are missing currently. (2) AMNH 185012 Solenodon paradoxus, New York Zoological Society, received June 2, 1960. This juvenile has the adult dentition, although the upper first incisor is not fully erupted and the teeth are generally unworn. Many cranial sutures are open, but fewer than in AMNH 28272. (3) AMNH 212912 Solenodon paradoxus, New York Zoological Society. This adult has few open sutures and 1/6/09 9:24:23 AM 2008 Wible—On the Cranial Osteology of Solenodon paradoxus 323 Fig. 1.—Reproduction of Gregory (1910: fig. 18) with the abbreviation list repositioned from the original. Included are lateral and ventral views in A1 and A2 respectively of the juvenile Solenodon paradoxus, AMNH 28272 that is restudied here. See text for various amendments (e.g., deciduous tooth loci; identification of orbitotemporal foramina; ethmoid orbital exposure rather than vomer). The long-tailed tenrec Microgale dobsoni, part of the original figure, is retained to illustrate the superficial dental and cranial resemblances to the solenodon. moderately worn dentition. (4) CM 18069 Solenodon paradoxus, male?, La Vega, Haiti, collected 1908. This adult has few open sutures and moderately worn dentition. Some soft tissues, including the proboscis, are still attached. Carnegie Museum of Natural History received this specimen on exchange from the Museum of Comparative Zoology (MCZ number was 34839). It was most likely part of the collection studied by Allen (1910), but he did not include specimen numbers. (5) AMNH 28271 Solenodon paradoxus, female, Haiti, collected 1907. This adult has few open sutures and the heaviest worn dentition of all specimens. Allen (1908: pl. 29–31) published photographs of the skull in dorsal, ventral, and left lateral views. According to Gregory Wible.indd 323 (1910:241), “the skull of an adult female (No. 28271) has been sectioned in the median line and affords valuable morphological details.” Currently, the skull is in three pieces: the right half, which includes the nasal septum; the left premaxilla and part of the left maxilla and nasal (to just behind the ultimate premolar); and the remainder of the left half. (6) MPIH 6863 Solenodon paradoxus, sectioned juvenile skull base including both ear regions. MacPhee (1981) described the tympanic surface of this specimen’s ear region in considerable detail, including the course of the basicranial arteries and nerves, and the origins of the tensor tympani and stapedius muscles. MacPhee (1981) listed this specimen as Solenodon sp., but it is identified as 1/6/09 9:24:25 AM 324 Annals of Carnegie Museum Vol. 77 S. paradoxus on the individual slides. During the past few years, the author and collaborators have published a number of treatments on cranial osteology of extinct and extant mammals (e.g., Wible and Rougier 2000; Wible 2003, 2007; Wible and Gaudin 2004; Wible et al. 2004, 2005a, in press; Giannini et al. 2006). The first choice in the evolving terminology in those publications is English equivalents of the Nomina Anatomica (fifth edition 1983) and Nomina Anatomica Veterinaria (fourth edition 1994), the latter abbreviated NAV in this paper. However, in instances where the Nominae are inadequate, employed are the most appropriate terms from the current comparative literature. Appendix 1 is a table of anatomical terms employed here along with references and equivalents; preceding the appendix is a glossary of cranial structures associated with nerves, arteries, and/or veins. An anatomical domain included in this report that is not included in the prior ones, except Giannini et al. (2006), is the nasal cavity. Terminology for the structures of the olfactory recess in the Nomina Anatomica Veterinaria (1994) and Evans (1993) follows that of Paulli (1900a, 1900b, 1900c) and Moore (1981). However, this terminology does not adequately discriminate the numerous scrolls and accessory scrolls of the olfactory recess. Therefore, principally Smith and Rossie (2006) and Maier (1993) are followed here. A similar circumstance involves the terminology for the auditory ossicles, where the Nomina Anatomica Veterinaria is supplemented by Henson (1961). For characterization of sutural types, Evans (1993:219) is followed: (1) serrated suture, “one that articulates by means of reciprocally alternating processes and depressions;” (2) squamous suture, “one that articulates by overlapping of reciprocally beveled edges;” (3) plane suture, “one in which the bones meet at an essentially right-angled edge or surface;” and (4) foliate suture, “one in which the edge of one bone fits into a fissure or recess of an adjacent bone.” The dentition of Solenodon, both deciduous and permanent, has been well documented (e.g., Leche 1907; Allen 1908; McDowell 1958; Thenius 1989) and will not be treated here. Nevertheless, a system of tooth identification is needed for descriptive purposes. Published dental formulae for Solenodon (e.g., Leche 1907; McDowell 1958; Thenius 1989) include three incisors, one canine, three premolars, and three molars in the upper and lower dentition. There are two principal ways to number the teeth in the classes with multiples in Solenodon, i.e., incisors, premolars, and molars. The first way is a simple numbering from one to three for each class (e.g., I1, I2, I3 for upper incisors; i1, i2, i3 for lower incisors); the second way employs a hypothesis of tooth position homology with reference to an ancestral condition with more teeth. The second is only relevant for the incisors and premolars of Solenodon, because its molar count of three is the same as that in basal eutherians (Ji et al. 2002; Kielan-Jaworowska et al. 2004). Regarding the premolars, two different hypotheses of reduction in the premolar series of Solenodon have already Wible.indd 324 been published. Without comment, some workers (e.g., Leche 1907; Gregory 1910) have referred to the premolars of Solenodon as P2, P3, P4, with the loss of the P1 from an ancestral condition of four premolars. In contrast, McDowell (1958) used P1, P2, P4, with the loss of the P3 from an ancestral condition of four premolars. McDowell (1958) identified the first upper premolar of Solenodon as P1, because it lacks a deciduous predecessor as is usually the case for the placental P1 (see also Luckett 1993); based on the morphology of the deciduous predecessors for the remaining two upper premolars, McDowell (1958) believed the permanent teeth to be most likely P2 and P4. A major complication to these two numbering systems (P2, P3, P4 and P1, P2, P4) is the current widespread view that the primitive eutherian premolar count is five and not four (McKenna 1975; Novacek 1986a, 1986b; Rougier et al. 1998; Nessov et al. 1998; Cifelli 2000; Kielan-Jaworowska et al. 2004; Wible et al. 2007, in press). The extra premolar of the five is in the middle of the series, and some authors (e.g., Cifelli 2000; Kielan-Jaworowska et al. 2004) number the five as P1, P2, Pc, P3, P4 to avoid confusion with the older literature, whereas others (e.g., Nessov et al. 1998; Wible et al. 2007, in press; this report) employ P1, P2, P3, P4, P5. A third hypothesis of homology for the three premolars of Solenodon based on a five premolar ancestral condition is proposed here: P1, P4, P5. In agreement with McDowell (1958), the upper first and third premolars of the three in Solenodon are the first and ultimate of the ancestral eutherian condition and, therefore, should be numbered P1 and P5 respectively. However, McDowell’s (1958) referral of the upper second premolar of Solenodon as the P2 of the ancestral eutherian condition is not accepted. Rather than the P2, the upper second premolar of Solenodon is the penultimate premolar of the ancestral five or P4. In the juvenile S. paradoxus AMNH 185012, the newly erupted upper second premolar is a tall, trenchant tooth set obliquely in the maxilla (Figs. 6, 11), resembling the penultimate premolar of most Cretaceous eutherians (Kielan-Jaworowska et al. 2004; Wible et al. 2004, 2007, in press); in the adults studied here this tooth is considerably worn (Fig. 7). Additionally, there is no instance within Eutheria in which the penultimate premolar is lost while a more anterior premolar is retained. Although McDowell (1958) ultimately identified the upper second premolar of Solenodon as P2 and the missing premolar as P3 (in the four premolar scheme), he stated (p. 160) that “there is some doubt whether the missing premolars in both upper and lower jaws are the second or the third.” The upper premolar formula hypothesized here for Solenodon (P1, P4, P5) is repeated in the lowers (p1, p4, p5) with the lower first premolar a permanent tooth without deciduous predecessor as occurs in the upper jaw (McDowell 1958). Regarding the incisors, no authors have offered explicit hypotheses of incisor homologies for Solenodon compared to the ancestral eutherian condition, which is widely held (e.g., Rougier et al. 1998; Ji et al. 2002; Kielan-Jaworowska 1/6/09 9:24:25 AM 2008 Wible—On the Cranial Osteology of Solenodon paradoxus 325 Fig. 2.—Solenodon paradoxus, AMNH 185012, drawings of skull in dorsal view. Abbreviations: fplac, facial process of lacrimal; fr, frontal; iof, infraorbital foramen; ip, interpariteral; M1r, anterolabial root of upper first molar; M3r, roots of upper third molar; me, mastoid exposure; mpfr, maxillary process of frontal; mx, maxilla; mxf, maxillary foramen; na, nasal; nc, nuchal crest; P5r, anterolabial root of upper ultimate premolar; pa, parietal; pdp, posterodorsal process of premaxilla; pmx, premaxilla; rt, foramina for rami temporales; sc, sagittal crest; so, supraoccipital; spp, septal process of premaxilla; sq, squamosal; zplac, zygomatic process of lacrimal; zpmx, zygomatic process of maxilla; zpsq, zygomatic process of squamosal. et al. 2004; Wible et al. 2007, in press) to be five uppers and four lowers. In fact, few authors have commented on the general problem within Placentalia caused by the presence of no more than three upper or lower incisors in all living group members (Thenius 1989). Ziegler (1971) suggested that the general pattern of incisor reduction in early therians was posteroanterior. There may be support for this in the upper incisors of some Late Cretaceous eutherians that have the posteriormost incisor either entirely within the maxilla (e.g., the fourth in the zalambdalestid Kulbeckia Nessov, 1993, according to Archibald and Averianov [2003]) or in the suture between the premaxilla and Wible.indd 325 maxilla (e.g., the fifth in the asioryctithere Asioryctes Kielan-Jaworowska, 1975, according to Kielan-Jaworowska [1981]). In contrast, placentals tend to have the posteriormost incisor entirely within the premaxilla, suggesting that it was the posteriormost incisors of the Late Cretaceous taxa that have been lost. Solenodon, for one, is an exception as its third incisor lies on the premaxillamaxilla suture (see Descriptions). At least one exception to Ziegler’s (1971) proposed posteroanterior direction of loss for early therians has been posited for the lower incisors of Cretaceous Zalambdalestidae by Archibald and Averianov (2003), who hypothesized that the i2 is lost in 1/6/09 9:24:28 AM 326 Annals of Carnegie Museum Vol. 77 with figures placed near the bone(s) of greatest relevance. For terms and synonyms, see Appendix 1; for information on cranial structures associated with nerves, arteries, and/ or veins, see Glossary before Appendix 1. Nasal (“na” in figures) Fig. 3.—Solenodon paradoxus, AMNH 185012, photograph of skull in anterior view. The anterodorsal aspect of the right premaxilla is damaged and exposes the opening into the alveolus of the I1. Also damaged are the tips of the right nasoturbinate and maxilloturbinate. Scale = 5 mm. Abbreviations: I1, upper first incisor; iof, infraorbital foramen; mt, maxilloturbinate; na, nasal; nt, nasoturbinate; pmx, premaxilla; spn, septal process of nasal; spp, septal process of premaxilla. Zalambdalestes Gregory and Simpson, 1926 (preserving i1, i3, i4) based on comparisons with the slightly older Kulbeckia (preserving i1–4). For now, the upper and lower incisors of Solenodon are numbered as I1–3 and i1–3 respectively without a hypothesis of incisor loss from the ancestral condition. The relevant extinct and extant forms considered to factor in the relationships of Solenodon provide no bases for hypothesizing incisor reduction, because these taxa have the same number of or fewer incisors than the solenodon (see Asher et al. 2002). Additionally, there does not appear to be a general rule of incisor reduction that can be applied to Solenodon or to any other placental at this point in time. Institutional Abbreviations AMNH—Department of Mammalogy, American Museum of Natural History, New York, New York CM—Section of Mammals, Carnegie Museum of Natural History, Pittsburgh, Pennsylvania MPIH—Neurobiologische Abteilung, Max-Planck-Institut für Hirnforschung, Frankfurt am Main, Germany DESCRIPTIONS The order of bone description follows that of previous publications on other mammals by the author (e.g., Wible 2003, 2007; Wible and Gaudin 2004; Giannini et al. 2006) Wible.indd 326 In dorsal view in AMNH 185012 (Fig. 2), the narrow, elongated paired nasal is more than 41% of greatest skull length with the maximum posterior extent just in front of the anterior orbital rim. The lateral margins are near parallel, widest posteriorly at their narrow contact where they underlie the maxillae (“mx” in Fig. 2). Anterior to the maxilla, the lateral margin has a lengthy contact where it underlies the premaxilla (“pmx” in Fig. 2). Posteriorly, the nasals form an elongate V underlying the frontals (“fr” in Fig. 2). The anterior margin of each nasal is concave, roughly U-shaped with a very short midline spine and a much longer lateral arm in contact with the premaxilla. The lateral arm does not reach as far forward as the premaxilla, and the nasals are recessed posteriorly at the osseous external nasal aperture. The nasals have half a dozen tiny foramina, asymmetrically arranged, mostly in the posteriormost surface. In anterior view (Fig. 3), the ventral surface of each nasal is concave, forming the roof of the dorsal nasal meatus. On the midline of the anterior ventral surface, the nasals produce a low, sharp ridge, the septal process (“spn” in Fig. 3). The septal process does not extend the length of the nasal, but is confined to roughly the anterior one-third. The medial ventrolateral surface has a raised rounded ridge, the nasoturbinate crest (“nt” in Fig. 3). Based on the left side of AMNH 28271 (Fig. 21B), the bisected skull, the nasoturbinate crest extends the length of the nasal. Posteriorly, it continues as the ethmoidal part of the nasoturbinate (Endoturbinale I of Paulli 1900a, 1900b, 1900c). In CM 18069 and AMNH 212912, the internasal suture is fused and the sutures between the nasals and their neighbors are barely perceptible (Fig. 4). The nasal is 40% of total skull length in the former and 37% in the latter. Os Proboscidis (“op” in Fig. 21B) CM 18069 and AMNH 28271 preserve the os proboscidis, the small bone at the posteroventral base of the proboscis named by Brandt (1833). In CM 18069, the bone is nearly circular (4.7 mm wide and 4.3 mm long) and held by ligaments to the premaxillae, anteroventral to the external nasal aperture (Fig. 12). Its ventral surface is more or less flat with anterior and posterior rims slightly elevated; a small foramen appears to the right of the midline. In AMNH 28271, the bone has been cut parasagittally (Fig. 20). The ventral surface resembles that of CM 18069, including the presence of a small foramen to the right of the midline. The dorsal surface has a rounded midline eminence that is roughly triangular in dorsal view, widest anteriorly where 1/6/09 9:24:29 AM 2008 Wible—On the Cranial Osteology of Solenodon paradoxus 327 Fig. 4.—Solenodon paradoxus, AMNH 185012, CM 18069, and AMNH 212912, photographs of skulls in dorsal views. Scale = 10 mm. Carat points are on the faint temporal lines in the bottom two specimens. Wible.indd 327 1/6/09 9:24:31 AM 328 Annals of Carnegie Museum Vol. 77 Fig. 5.—Solenodon paradoxus, AMNH 28272, photograph and line drawing of braincase in dorsal view; rostrum is preserved separately. Abbreviations: fr, frontal; ip, interparietal; me, mastoid exposure of petrosal; mx, maxilla (broken); mxfc, facet for maxilla on frontal; na, nasal (broken); nc, nuchal crest; pa, parietal; pet, petrosal; rt, foramina for rami temporales; so, supraoccipital; sq, squamosal; zpsq, zygomatic process of squamosal. the eminence continues laterally as a rounded, raised rim that turns posteriorly to form a lateral rim. The midline eminence is flanked on either side by a depression that contains several small foramina. In medial view (Figs. 20, 21A, B), the section of the os proboscidis is cigar shaped with the ventral side slightly concave and the dorsal convex. Premaxilla (“pmx” in figures) In AMNH 185012 (Figs. 6, 11), the paired premaxilla houses three incisors that decrease in size posteriorly, the I1, I2, and I3. The I1 is set transversely, whereas the I2 and I3 are longitudinally arranged. The I1 is separated from the I2 by a diastema equivalent in length to the I3. In the posterior half of this diastema is a small, empty alveolus Wible.indd 328 that likely housed the dI2. AMNH 28271 and 212912 have three incisors (Fig. 7), with the diastema between I1 and I2 longer than the length of the I2. CM 18069 differs in that it has four incisors (Figs. 7, 12); the first two are clearly the I1 and I2, but the identity of the third and fourth teeth is unclear. The extent of wear is comparable on the two teeth and not significantly different from their neighbors, leading the author to posit that both are likely adult teeth. There is some asymmetry: on the left side the third tooth is subcircular and smaller than the subtriangular fourth tooth, whereas on the right the third tooth is compressed anteroposteriorly and the subequal fourth tooth is subcircular. Given that published tooth formulas for Solenodon include three upper incisors (e.g., Leche 1907; Thenius 1989), it is assumed here that CM 18069 represents a supernumerary condition. 1/6/09 9:24:37 AM 2008 Wible—On the Cranial Osteology of Solenodon paradoxus 329 Fig. 6.—Solenodon paradoxus, AMNH 185012, drawings of skull in left lateral view. Abbreviations: aof, antorbital fossa; as, alisphenoid; C, upper canine; eo, exoccipital; eth, ethmoid; fr, frontal; gf, glenoid fossa; ham, pterygoid hamulus; hf, hypoglossal foramina; I1, upper first incisor; I2, upper second incisor; I3, upper third incisor; imc, incisivomaxillary canal; iof, infraorbital foramen; ip, interparietal; lac, lacrimal; lacf, lacrimal foramen; lacfe, lacrimal fenestra; M1, upper first molar; M2, upper second molar; M3, upper third molar; M3r, roots of upper third molar; me, mastoid exposure of petrosal; mpfr, maxillary process of frontal; mx, maxilla; na, nasal; nc, nuchal crest; oc, occipital condyle; os, orbitosphenoid; otcr, orbitotemporal crest; P1, upper first premolar; P4, upper penultimate premolar; P5, upper ultimate premolar; pa, parietal; pal, palatine; pdp, posterodorsal process of premaxilla; pmx, premaxilla; rt, foramina for rami temporales; so, supraoccipital; spf + mpf, sphenopalatine and minor palatine foramina; sq, squamosal; zm, zygomaticus minor attachment. Sutures delimiting the premaxillae are well preserved in the juveniles AMNH 28272 and 185012, with the following based on the latter. In lateral view (Fig. 6), the facial process is roughly rectangular, longer than tall, and taller anteriorly than posteriorly to accommodate the large I1. The alveolus for the I1 is more ventrally positioned than that of the posterior incisors, with AMNH 212912 showing the most extreme differential in that feature (Fig. 7). The I1 in AMNH 185012 is still erupting and is roughly perpendicular to the postcanine occlusal surface, whereas the fully erupted tooth in CM 18069 and AMNH 28271 and 212912 is slanted posteroventrally (Fig. 7). The facial process has a tail (the posterodorsal process) extending from the posterodorsal corner to just beyond the level of the posterior root of the canine (“pdp” in Fig. 6). Not including the posterodorsal process, the facial process represents more than 45% of the pre-orbital length, measured at the lacrimal foramen. The ventral border of the posterodorsal Wible.indd 329 process underlies the maxilla; the posterior border of the facial process has a plane suture with the maxilla dorsally and underlies that bone ventrally. The anterior border of the facial process is convex. The dorsal half of that convexity is the premaxilla’s contribution to the external nasal aperture; the ventral half is the extensive suture between the right and left premaxillae, which slopes anterodorsally. The surface of the facial process has a bulge over the root of the I1, but this is flatter in CM 18069, AMNH 28171 and 212912. In all four specimens, the facial process contains half a dozen tiny foramina, asymmetrically arranged, mostly in the posteriormost surface (Fig. 6). In ventral view (Fig. 11), the premaxilla includes the alveolar process housing the incisors and the palatine surface, with the palatine process on the midline (“ppp” in Fig. 11). In AMNH 185012, the alveolus for the I3 is not entirely within the premaxilla; its posterior border is formed by maxilla. Sutures delimiting the premaxillae and 1/6/09 9:24:38 AM 330 Annals of Carnegie Museum Vol. 77 Fig. 7.—Solenodon paradoxus, AMNH 185012, AMNH 28271, CM 18069, and AMNH 212912, photographs of skulls in lateral views. Scale = 10 mm. maxillae are all but obliterated in CM 18069 and AMNH 28271 and 212912 (Fig. 7). Nevertheless, there is faint indication at the alveolar margin that the premaxilla in these adults is as in the juvenile and does not completely enclose the alveolus of I3 (or the fourth incisor in CM 18069). The palatine surface is a small contributor to the surface area of the hard palate. It occupies the area immediately behind the Wible.indd 330 anteriormost incisor and medial to the diastemata between the first and second incisors. At the level of the diastema is the oval incisive foramen, whose length approximates that of the third incisor (“inf” in Fig. 11). The incisive foramen is almost completely within the premaxilla, with the palatine process of the maxilla forming the narrow posteriormost border. The maxillae overlap the premaxillae 1/6/09 9:24:40 AM 2008 Wible—On the Cranial Osteology of Solenodon paradoxus at the M-shaped palatal suture, with the narrow paired palatine processes of the premaxillae forming the central arm, the base of which is opposite the middle of the third incisor. In anterior view (Fig. 3), the premaxillae’s contribution to the external nasal aperture has the shape of a cursive W, with the middle arm of the W much lower than the lateral arms. The top half of each lateral arm is much thicker than the lower half. Behind the middle arm of the W, in the floor of the nasal cavity is a narrow gap and then a raised longitudinal crest on each premaxillae, angled roughly 30° from the sagittal plane. This crest, the septal process (“spp” in Fig. 3), extends the length of the premaxilla, from the dorsal surface of the premaxillary body anteriorly to the dorsal surface of the posterior extent of the narrow palatine process discussed above (Fig. 9). In life, the Vshaped space between these crests, the sulcus septi nasi, housed the bottom of the nasal septum, the bulk of which was cartilaginous in this region (see Fig. 20). In AMNH 28272, the posterior ends of the septal processes of the premaxillae are sandwiched between the lateral laminae of the vomer medially (“llv” in Fig. 9) and the septal processes of the maxillae laterally. Between the septal process of the premaxilla and the nasoturbinate crest is the maxilloturbinate or ventral nasal concha (“mt” in Fig. 3). In the medial wall of the nasal cavity in AMNH 28271, 28272, and 212912, there is a sharp conchal crest (“ccp” in Figs. 9, 21B), upon which the anterior part of the maxilloturbinate rests. The conchal crest does not extend the full length of the premaxilla, because it is recessed slightly from the anterior margin. Maxilla (“mx” in figures) The paired maxilla has an alveolar process housing the canine and postcanine dentition, which includes three premolars (P1, P4, P5) and three molars (M1–3) (Figs. 6, 11); as noted by Gregory (1910: fig. 18A1, A2; see Fig. 1) in the juvenile AMNH 28272 the second and third premolars are deciduous teeth (Figs. 8, 9). Each maxilla has a facial, palatal, orbital, and nasal surface, of which the last is visible only in AMNH 28271 and 28272. Sutures delimit the maxilla from its neighbors in the juveniles AMNH 28272 and 185012, except that in the latter the orbital suture with the lacrimal is partially fused (“lac” in Figs. 6, 8, 10, 11). In CM 18069, AMNH 28271 and 212912, the maxilla is delimited from the palatine on the palate (Fig. 12) and, in the first only, from the lacrimal on the face and partially within the orbit (Fig. 7). In lateral view in AMNH 185012 (Fig. 6), the vertical anterior border of the facial surface contacts the premaxilla, the horizontal dorsal border contacts the premaxilla, nasal, and frontal, and the concave posterior border contacts the frontal and lacrimal. The maxilla overlaps the premaxilla, nasal, and frontal, but most of the suture with the lacrimal is plane. The most prominent feature of the facial surface is the large infraorbital foramen (“iof” in Wible.indd 331 331 Fig. 6), the anterior opening of the short infraorbital canal (slightly less than the length of M1). The infraorbital foramen is positioned dorsal to the anterolingual root of M1 in all specimens. In anterior view (Fig. 3), the infraorbital foramen is oval, slightly taller than wide. Anterior to the infraorbital foramen, dorsal to the anterolingual root of the ultimate premolar, as well as in the floor of the infraorbital canal, are several alveolar foramina transmitting superior alveolar nerves and vessels (“imc” in Fig. 6; “af” in Fig. 10). The course of the anteriormost alveolar canal can be traced through the thin bone in the juvenile AMNH 185012 nearly to the premaxilla-maxilla suture because dark tissue has dried within the canal. In light of this course, it is equivalent to the incisivomaxillary canal of the dog (Evans 1993). Anterodorsal to the anteriormost alveolar canal is a tiny foramen that appears to emanate from the nasolacrimal canal. Between the infraorbital foramen and the frontal suture is a broad, shallow, ovoid antorbital fossa (“aof” in Fig. 6) for the origin of levator labii superioris proprius (Whidden 2002). The posteroventral margin of the facial surface forms the anteroventral orbital rim and the short anterior zygomatic process (“zpmx” in Figs. 2, 11). The outer edge of the orbital rim has a raised, rounded orbital crest, anteroventral to which in the adults is a pronounced depression (“zm” in Fig. 6), for the zygomaticus minor (Whidden 2002). The zygomatic process tapers to a thin rod that projects posterodorsally opposite the back of M3 (Figs. 4, 7, 12). In ventral view, the palatine processes of the maxillae are the major components of the hard palate, extending from the back of the incisive foramina at the level of the anterior edge of I2 to the narrow wall posterior to M3 with only a small, shield-shaped cutout for the palatine bones posterior to M1 (“pal” in Fig. 11). The maxilla underlies the palatine in their palatal suture. Each palatine process of the maxilla contains many small foramina, in particular medial to P1 and P4 and in the interdental spaces between P5/M1, M1/M2, and M2/M3 (Figs. 11, 12). In addition, AMNH 185012 has a small foramen in the palatomaxillary suture opposite the M2 protocone (“mapf” in Fig. 11); AMNH 28271 has two such foramina, both opposite the M2 protocone on the right side but with the posterior one on the left side opposite the anterior edge of the M3; AMNH 212912 has three such foramina, the anterior two opposite M2 and the posteriormost opposite the M2/M3 interdental space; and CM 18069 has an additional posterior one opposite the M3 postcingulum (the naming of these foramina is considered with the palatine bone). The intermaxillary suture is flat in AMNH 185012, slightly raised in AMNH 28272, fused and slightly raised in CM 18069 and AMNH 28271, and fused and with a noticeable crest in AMMH 212912 (Fig. 12). Also visible in ventral view is the short zygomatic process of the maxilla, the posterior root of which is opposite the M3 paracone in all specimens. Gregory (1910:244, fig. 18A2; see Fig. 1) observed that “in the young skull (AMNH 28272) the palatal plates 1/6/09 9:24:40 AM 332 Annals of Carnegie Museum Vol. 77 Fig. 8.—Solenodon paradoxus, AMNH 28272, photograph and line drawing of right rostrum (premaxilla, maxilla, and lacrimal) in lateral view. Abbreviations: C, upper canine; dI1, upper first deciduous incisor; dI2, upper second deciduous incisor; dP4, upper penultimate deciduous premolar; dP5, upper ultimate deciduous premolar; I1, upper first incisor; iof, infraorbital foramen; lac, lacrimal; lacf, lacrimal foramen; lacfe, lacrimal fenestra; M1, upper first molar; M3r, roots of upper third molar; mx, maxilla; mxf, maxillary foramen; P1, upper first premolar; P5, upper ultimate premolar; pdp, posterodorsal process of premaxilla; pmx, premaxilla; zpmx, zygomatic process of maxilla. of the maxillary do not come together completely at the posterior end in the mid line and in the adult skulls is a small fenestra at this point. This was also noted in Mivart (1868, p. 124) in S. cubanus.” Allen (1908:515) noted in AMNH 28270 and 28271 that “both adult skulls show a small longitudinal vacuity in the palatine, but they look more like accidental fractures than normal vacuities.” Regarding AMNH 28271, the specimen has been bisected off the midline and there is no sign of a fenestra on the larger right hand side. The other adult S. paradoxus studied here show absolutely no fenestra at this point (Fig. 12), nor does the specimen photographed in Thenius (1989: fig. 143). In the juvenile AMNH 185012 the two maxillae are clearly separated along their entire midline suture (Fig. 12), but this is separation resulting from the immature stage of the Wible.indd 332 specimen and not a palatal vacuity. Based on sutural information from AMNH 185012 and 28272, the maxilla within the orbit contributes (Figs. 6, 10), to the anteroventral wall, the floor, and the ventral orbital rim. The maxillary foramen, the posterior opening into the infraorbital canal, is entirely within the maxilla (“mxf” in Figs. 8, 10); the lacrimal approaches the dorsal border of the foramen but is excluded but a 1–2 mm sliver of maxilla. In the anteroventral wall, the maxilla contacts the lacrimal dorsally at a horizontal plane suture, overlaps the frontal posterodorsally at an irregular serrated suture that is slanted posteroventrally, and overlaps the ethmoid at an irregular suture that is slanted anteroventrally (“eth” in Figs. 6, 10). In the pterygopalatine fossa, posteromedial to M3, the maxilla has a narrow squamous suture with the 1/6/09 9:24:46 AM 2008 Wible—On the Cranial Osteology of Solenodon paradoxus 333 Fig. 9.—Solenodon paradoxus, AMNH 28272, photograph and line drawing of right rostrum (premaxilla, maxilla, lacrimal, and part of the vomer) in medial view. Abbreviations: ccm, conchal crest of maxilla; ccp, conchal crest of premaxilla; cP5, crypt for upper ultimate premolar; dI1, upper first deciduous incisor; dI2, upper second deciduous incisor; dP4, upper penultimate deciduous premolar; dP5, upper ultimate deciduous premolar; eths, surface for ethmoid bone; frs, surface for frontal bone; I1, upper first incisor; I2, upper second incisor; lac, lacrimal; llv, lateral lamina of vomer; M1, upper first molar; mx, maxilla; nlc, nasolacrimal canal; P1, upper first premolar; pdp, posterodorsal process of premaxilla; pmx, premaxilla; rm, recessus maxillaris; ronlc, rostral opening of nasolacrimal duct; spp, septal process of premaxilla. palatine (Fig. 10). A tiny sliver of maxilla in the anterodorsal part of the palatomaxillary suture contributes to the dorsal margin of the sphenopalatine foramen, which is closed by the palatine and ethmoid (“spf” in Fig. 10). In the ventral orbital rim, the maxilla is overlapped by the lacrimal (“zplac” in Fig. 2). In the juvenile AMNH 185012 (Figs. 6, 10), some roots of the ultimate premolar and the molars are exposed on the face and in the orbit, because the maxilla fails to contain them: specifically the anterolabial root of P5 in front of the infraorbital foramen, the anterolabial root of M1 ventrolateral to the infraorbital foramen, and within the orbit the lingual root of M2 and all three roots of M3. In the adults (Figs. 4, 7), roots are not exposed on the face and the exposure differs within the orbit. Exposed in CM Wible.indd 333 18069 are all three roots of M2 and the two labial roots of M3, in AMNH 212912 are all three roots of M3 and the lingual root of the right M2, and in AMNH 28271 are only the labial roots of the left M3 and the posterolabial root of the right M3. In addition to the exposed molar roots, the orbit floor is riddled with numerous small openings in the juvenile AMNH 185012 (Fig. 2). Most of these are not preserved in the adults, although several foramina are evident in all specimens between the lingual roots of M2 and M3, which may transmit additional superior alveolar branches. Exposed in the juvenile AMNH 28272 is the medial surface of the disarticulated maxillae (Fig. 9), which contributes to the floor and lateral wall of the nasal cavity. The most salient feature is the conchal crest for the ventral 1/6/09 9:24:54 AM 334 Annals of Carnegie Museum Vol. 77 lateral to the lateral lamina of the vomer (not visible in the figures). The septal process is not of uniform height, but is low anteriorly and posteriorly and nearly as tall as the vomer in between. Ventral Nasal Concha (“mt” in figures) Fig. 10.—Solenodon paradoxus, AMNH 185012, photograph of right orbit in oblique posterior view. Carats points outline the fusing suture between the lacrimal and maxilla. Scale = 5 mm. Abbreviations: af, alveolar foramen; eth, ethmoid; fr, frontal; lac, lacrimal; lacf, lacrimal foramen; lacfe, lacrimal fenestra; M3, upper third molar; mpf, minor palatine foramen (dorsal opening); mx, maxilla; mxf, maxillary foramen; pal, palatine; spf, sphenopalatine foramen; y, bar of bone forming posterior border of minor palatine foramen, which is absent in CM 18069 (Fig. 13B). nasal concha (maxilloturbinate), which extends from the premaxillary conchal crest to the level of the M1 (“ccm” in Fig. 9). The maxillary conchal crest is much sharper and protuberant than that on the premaxilla. The crest is concave ventrally, more dorsal and lateral anteriorly and more ventral and medial posteriorly. Also visible between the level of the P1 and dP5 is the bulge produced by the nasolacrimal canal (“nlc” in Fig. 9). This bulge begins posteriorly at the suture between the maxilla and lacrimal and runs obliquely in an anteroventromedial direction. The bulge intersects the conchal crest opposite the middle of P1, and the nasolacrimal canal opens beneath the conchal crest into the ventral nasal meatus anterior to that (“ronlc” in Fig. 9). In the interval posterior to the intersection of the conchal crest and nasolacrimal canal is an opening into the crypt of the P5 (“cP5” in Fig. 9). At the posterior margin of the medial maxillary surface ventral to the lacrimal is a boot-shaped surface, with the toe pointing anteriorly. The heel and throat (crural part) of the boot overlap the frontal bone in the orbit (“frs” in Fig. 9) and the toe overlaps the lateral wall of the ethmoid (“eths” in Fig. 9). The surface anterior to the boot contributes to the lateral wall of the maxillary recess (see Ethmoid; “rm” in Fig. 9); a maxillary sinus is lacking. The maxilla’s contribution to the floor of the nasal cavity is flat, except along the dorsal surface of the intermaxillary suture, where there is a septal process Wible.indd 334 The paired ventral nasal concha or maxilloturbinate attaches via a basal lamina to the conchal crests on the medial wall of the maxilla and premaxilla. The left side of the bisected skull AMNH 28271 preserves much of the ventral nasal concha (Fig. 21B); missing are small segments near the external nasal aperture and opposite the P4 and P5. Anteriorly, the basal lamina of the ventral nasal concha is perpendicular to the lateral nasal wall, but posteriorly it is near vertical. The pointed anterior end of the ventral nasal concha is visible through the external nasal aperture in AMNH 185012 (Fig. 3). Immediately distal to the pointed end, the ventral nasal concha is roughly C-shaped in cross section, with horizontal and vertical arms, the former, the basal lamina, attached to the lateral nasal wall. Proceeding distally into the nasal cavity, four primary scrolls are identified, dorsoventrally, from one to four, based on the left side of the bisected skull AMNH 28271 (Fig. 21B). The first leaves the dorsal surface of the basal lamina at the level of the I2 and is displaced posterolaterally by ethmoturbinate I. The second arises from the dorsal surface at the pointed anterior end, but assumes a dorsomedial position posteriorly, ending medial to ethmoturbinate II. The third arises from the medial surface between the canine and P4, but its full posterior extent is uncertain because of damage. The fourth scroll is only visible at the level of P4 where it lies beneath the maxillary conchal crest; the anterior and posterior ends of this scroll are unknown. Three spaces within the nasal cavity are associated with the ventral nasal concha: dorsally is the middle nasal meatus, medially is the common nasal meatus, and ventrally is the ventral nasal meatus. Palatine (“pal” in figures) The paired palatine is a small element contributing to the back of the hard palate and the floor of the nasopharyngeal meatus via a horizontal process, and to the medial wall of the pterygopalatine fossa and the lateral wall of the choanae and basipharyngeal canal via a perpendicular process. The horizontal processes of the palatines are delimited from the maxillae by sutures in all specimens (Figs. 11, 12); the interpalatine suture is fused in CM 18069 and AMNH 28271; and the sutures with other elements in the pterygopalatine fossa and basipharyngeal canal are fusing or fused in the adults (Figs. 6, 7). On the palate (Fig. 11), the horizontal processes are shield-shaped, with each specimen showing some leftright asymmetry in the outer contour of the palatomaxillary suture. The palatal surface of the palatine is fairly flat 1/6/09 9:24:54 AM 2008 Wible—On the Cranial Osteology of Solenodon paradoxus 335 Fig. 11.—Solenodon paradoxus, AMNH 185012, drawings of skull in ventral view. Abbreviations: as, alisphenoid; bo, basioccipital; bs, basisphenoid; C, upper canine; e, ectotympanic; eo, exoccipital; fm, foramen magnum; gf, glenoid fossa; ham, pterygoid hamulus; I2, upper second incisor; inf, incisive foramen; M1, upper first molar; mapf, major palatine foramen; me, mastoid exposure of petrosal; mpf, minor palatine foramen; mx, maxilla; oc. occipital condyle; os, orbitosphenoid; P4, upper penultimate premolar; pa, parietal; pal, palatine; pet, petrosal; pmx, premaxilla; ppp, palatine process of premaxilla; ppt, postpalatine torus; pr, promontorium of petrosal; ps, presphenoid; pt, pterygoid; so, supraoccipital; sof, sphenorbital fissure; v, vomer; zpmx, zygomatic process of maxilla; zpsq, zygomatic process of squamosal. except along its posteriormost border, which sports a pronounced postpalatine torus (“ppt” in Fig. 11), especially in the adults with parts showing considerable rugosity (Fig. 12). At the lateral limit of the postpalatine torus is the minor palatine foramen (“mpf” in Fig. 11), which shows variability in the studied specimens related to the passage of two principal neurovascular bundles from the pterygopalatine fossa, one directed anteriorly onto the hard palate and the other posteriorly into the soft palate. The juvenile AMNH 185012 and the left side of AMNH 212912 have a narrow gap in the postpalatine torus (gap lies between the asterisks in Fig. 13A); dorsal to this gap is a foramen (“dor” in Fig. 13A), which connects to the pterygopalatine fossa (“mpf” in Fig. 10). On the right side of AMNH 212912, the narrow gap in the postpalatine torus described above is closed by Wible.indd 335 bone (“x” in Fig. 13A), and three separate foramina are delimited, which for descriptive purposes are called dorsal, anteroventral, and posteroventral minor palatine foramina (“dor”, “ant”, and “post” in Fig. 13A). The dorsal is interpreted as transmiting the minor palatine nerve and vessels from the pterygopalatine fossa (“mpf” in Fig. 10); the anteroventral transmits branches to the back of the hard palate; and the posteroventral transmits branches to the soft palate. CM 18069 has no gap in the postpalatine torus (that is, “x” is present in Fig. 13B), but it differs in that the bar of palatine bone forming the posterior border of the dorsal minor palatine foramen in the other specimens (“y” in Figs. 10, 13A) is absent (“y absent” in Fig. 13B); it has only one minor palatine foramen equivalent to the anteroventral foramen of the right side of AMNH 212912 (“ant” in Fig. 13). 1/6/09 9:24:56 AM 336 Annals of Carnegie Museum Vol. 77 Fig. 12.—Solenodon paradoxus, AMNH 185012, CM 18069, and AMNH 212912, photographs of skulls in ventral views. Scale = 10 mm. Wible.indd 336 1/6/09 9:24:57 AM 2008 Wible—On the Cranial Osteology of Solenodon paradoxus In addition to the foramina in the palatomaxillary suture described with the maxillary bone, the horizontal process of the palatine is pierced by a variable number of small foramina showing considerable left-right asymmetry in number and position (Fig. 12). CM 18069 has the fewest with one on the right and two on the left; AMNH 212912 has four on both sides; and AMNH 185012 has four on the left and five on the right (cf. Figs. 11, 13). In the dog (Evans 1993), the accessory palatine nerves exit via one or more openings in the horizontal process (accessory palatine foramina of Wible and Gaudin 2004) and the major palatine nerve exits via one opening in the anterior palatomaxillary suture (major palatine foramen of Evans 1993). Those criteria are followed here for Solenodon and the openings in or adjacent to the anterior palatomaxillary suture are called the major palatine foramina and all others accessory palatine foramina. Based on the bisected skull AMNH 28271 (Fig. 21B), the dorsal surface of the horizontal process, which forms the floor of the nasopharyngeal meatus anterior to the choanae, is essentially featureless. The left side has two foramina, a larger anterior one opposite the M2/M3 embrasure and a smaller posterior one opposite the M3 (“mapf” and “apf” in Fig. 22). The former is likely for the major palatine nerve and the latter for the accessory palatine nerve. Posterolateral to these openings is a large foramen with a groove extending anteriorly from it (“spf” in Figs. 21B, 22), the anterior opening of a short canal leading from the sphenopalatine foramen in the pterygopalatine fossa. Based on the juveniles AMNH 28272 and 185012, this opening is between the palatine and ethmoid. The right side of AMNH 28271 (Fig. 20), which includes the midline is flat, with any foramina present covered by connective tissue. Posterior to the postpalatine torus, the back edge of the horizontal processes form the floor of the choanae (Fig. 11). The back edge of each horizontal process is concave and they meet on the midline to form a short posterior nasal spine (“pns” in Fig. 13), although in AMNH 212912 they meet off the midline and most of the spine is on the right palatine (Fig. 13A). Most of the lateral walls of the choanae and of the anterior half of the basipharyngeal canal behind the choanae is formed by the medial side of the perpendicular process of the palatine, with the vomer completing the walls and forming the roof (“v” in Fig. 11). The vomer overlaps the palatine anteriorly, but the vomeropalatine suture is plane posteriorly. Forming the walls of the basipharyngeal canal posterior to the palatines are the pterygoids (“ham” in Fig. 11). The lateral side of the perpendicular process forms the medial wall of the pterygopalatine fossa and is entirely excluded from the orbit (Figs. 6, 14). The lateral side of the perpendicular process has squamous sutures with the ethmoid and orbitosphenoid dorsally and the alisphenoid and pterygoid posteriorly (“eth”, “os”, “as”, and “pt” in Fig. 14). The anterior end of the lateral side of the palatine’s perpendicular process contributes to the formation of two foramina in the pterygopalatine fossa, a larger more oval dorsal one, Wible.indd 337 337 Fig. 13.—Solenodon paradoxus, photographs of rear aspect of palate in ventral view. A, AMNH 212912; B, CM 18069. Scale = 5 mm. In A, on the specimen’s right side, the course of the minor palatine nerve is via three conduits: a dorsal one, the only complete foramen, that opens into the pterygopalatine fossa in the orbit (Fig. 10); an anteroventral one that opens onto the back of the hard palate; and a posteroventral one that opens onto the soft palate. The bar of bone (x) separating the anteroventral and posteroventral foramina on the right side is incomplete on the left side (*). In B, the bar of bone (y) forming the posterior margin of the dorsal foramen in A is lacking. Anterior to the postpalatine torus are a number of foramina in the palatine or in the palatomaxillary suture; those in or near the anterior palatomaxillary suture are termed major palatine foramina and the remainder are accessory palatine foramina (see Palatine). Abbreviations: ant, anteroventral minor palatine foramen; dor, dorsal minor palatine foramen; pal, palatine; pns, posterior nasal spine; post, posteroventral minor palatine foramen; ppt, postpalatine torus. the sphenopalatine foramen (which includes the sphenopalatine and caudal palatine foramina of the dog (Evans 1993), and a circular ventral one that is slightly more posterior, the (dorsal) minor palatine foramen already mentioned above (“spf” and “mpf” in Fig. 10). The palatine forms the ventral half of the sphenopalatine foramen, which is completed by the ethmoid and a sliver of maxilla. 1/6/09 9:24:58 AM 338 Annals of Carnegie Museum Vol. 77 Fig. 14.—Solenodon paradoxus, AMNH 185012, line drawing of left orbit in oblique lateral view. Position of ethmoid is based on AMNH 28272 (see “oleth” in Fig. 16). Abbreviations: aef, anteroventral ethmoidal foramen; as, alisphenoid; asc, alisphenoid canal; bs, basisphenoid; eth, ethmoid; fdv, foramen for frontal diploic vein; fo, foramen ovale; fr, frontal; gf, glenoid fossa; ham, pterygoid hamulus; mpf, minor palatine foramen (dorsal opening); mx, maxilla; of, optic foramen; os, orbitosphenoid; otc, anterior opening of orbitotemporal canal; pa, parietal; pal, palatine; pef, posterodorsal ethmoidal foramen; pf, piriform fenestra (of opposite side); pt, pterygoid; sof, sphenorbital fissure; spf, sphenopalatine foramen; sq, squamosal; zpsq, zygomatic process of squamosal. Lacrimal (“lac” in figures) The paired lacrimal is a small bone placed high in the anterior orbital rim (Figs. 2, 6). It has a very narrow, crescentic facial process that is overlapped anteriorly by the maxilla (“fplac” in Fig. 2). The posterior aspect of the facial process is thickened and forms the anterior orbital rim. The lacrimal orbital crest is thickest in its central part, but not enough to identify as a lacrimal tubercle. The orbital crest curves posteroventrally as a zygomatic process of the lacrimal (“zplac” in Fig. 2) onto the dorsal root of the zygomatic process of the maxilla. The lacrimal is fully delimited from its neighbors in AMNH 28272 (Figs. 8, 9), nearly so in AMNH 185012 and CM 18069, with the orbital suture with the maxilla fusing (Fig. 10), and not differentiated at all in AMNH 28271 and 212912 (Figs. 4, 7). In AMNH 185012, immediately posteromedial to the orbital rim within the orbit is the large, oval lacrimal foramen (in essence, the fossa for the lacrimal sac), taller than wide, which narrows anteriorly into the circular nasolacrimal canal for the nasolacrimal duct (“lacf” in Fig. 10). The orbital surface of the lacrimal is narrow posteromedial and posteroventral to the lacrimal foramen where the lacrimal contacts the maxilla at a plane suture and widest posterodorsally where the lacrimal overlaps the frontal. Within the orbit, the lacrimal overlaps the frontal dorsally and posterodorsally, contacts the orbital surface of the Wible.indd 338 maxilla posteriorly, and overlaps the zygomatic process of the maxilla posteroventrally (Figs. 2, 10). The suture with the zygomatic process of the maxilla is nearly completely fused and that with the orbital surface is fusing. Within the latter suture (also in AMNH 28272), dorsal to the maxillary foramen is a narrow slit that likely represents a lacrimal fenestra for the inferior oblique muscle (“lacfe” in Figs. 6, 8, 10; Wible and Gaudin 2004). Dorsal to the lacrimal fenestra in AMNH 28272 and 185012 is a small vascular foramen reminiscent of that described in Pteropus Brisson, 1762, by Giannini et al. (2006). In AMNH 28271, 212912, and CM 18069, the lacrimal fenestra is replaced by a narrow pit with the closure of the suture between the lacrimal and maxilla (Fig. 7). The lacrimal is not as fully formed in the juvenile AMNH 28272 as in the remaining specimens. Unlike the adults, its lacrimal does not completely enclose the nasolacrimal canal, with the ventrolateral margin formed by the maxilla (Fig. 8). The medial surface of the lacrimal is visible on the right side of AMNH 28272 (Fig. 9). It is wedge shaped, with the point directed anteriorly, and dorsally and ventrally has plane sutures with the maxilla. At the posterior limit is a small triangular surface that overlaps the frontal in the orbit. The remainder of the medial surface of the lacrimal contributes to the maxillary recess (see Ethmoid). 1/6/09 9:25:00 AM 2008 Wible—On the Cranial Osteology of Solenodon paradoxus Jugal The absence of a paired jugal bone has long been accepted as a feature of the Hispaniolan solenodon (Gregory 1910; Muller 1934), and all specimens examined here agree. Frontal (“fr” in figures) The paired frontal bone contributes to the braincase roof via the squama frontalis and to the medial orbital wall via the pars orbitalis. AMNH 28272 is the only specimen with sutures delimiting the entire frontal (Figs. 5, 16); in AMNH 185012 some sutures within the orbit are not visible (Figs. 6, 14) and most of the interfrontal suture on the skull roof is obliterated (Fig. 2). The squama frontalis is described based on AMNH 185012 (Fig. 2); differences from the other specimens are noted below. At the midline, the squama comprises less than 20% of total skull length; at its greatest length, which includes the elongate maxillary process (“mpfr” in Figs. 2, 6), the squama is more than 30% of total skull length. The squama can be visualized as an ice cream cone, with the tip of the cone projecting anteriorly as the maxillary process. The maxillary process tapers to a point reaching the level of the anterior (mesial) root of P4; it is separated from the posterodorsal process of the premaxilla by approximately 4 mm. The maxillary process contacts the nasal anteromedially and the maxilla anterolaterally. The posterior interfrontal suture is raised slightly as the low, anteriormost sagittal crest. Half a dozen small foramina are asymmetrically arranged just off the midline of the interfrontal suture. At its lateral limit, the squama bends ventrally into the orbit as the pars orbitalis; a distinct orbital rim is lacking and there is virtually no postorbital constriction. Posteriorly, the squama is overlapped by the parietal (“pa” in Fig. 2) along an asymmetric suture. The bulk of the suture is roughly transverse, but at the midline is a small, irregular U-shaped exposure of frontal between the parietals. The surface of the squama is generally flat, with a slight bulging towards the pars orbitalis. The squama frontalis of the adult specimens (Fig. 4) differs in that the sagittal crest is slightly more raised and it continues forward into low temporal lines that arch ventrolaterally into the anterior orbital rim at the lacrimal and are too subtle to see in direct dorsal view. With this forward position for the temporal line, the length of the temporal fossa is more than 50% of total skull length. The squama frontalis of the more immature juvenile AMNH 28272 differs in that, as noted above, the interfrontal suture is retained, the midline foramina and sagittal crest are absent, and the sutures with the parietals are entirely transverse (Fig. 5). The pars orbitalis in AMNH 28272 is fully delimited from its neighbors (Fig. 11), whereas in AMNH 185012 the ventral borders are unclear (Figs. 6, 14). The anterior sutures with the lacrimal and maxilla have been described above. Posterodorsally, the pars orbitalis overlaps the Wible.indd 339 339 parietal at a vertical suture. Ventral to the parietal, the frontal underlies a narrow anteriorly directed process of the alisphenoid (Fig. 6), which is twice as tall on the right side as on the left in AMNH 185012. In AMNH 28272 (Fig. 16), the frontal inferior to its contact with the alisphenoid has two short, quadrangular processes, one directed ventrally and the other posteriorly. The ventral process contacts the maxilla anteriorly, the ethmoid (the vomer of Gregory 1910; see Fig. 1) ventrally, and the orbitosphenoid posteriorly, and the posterior process contacts the alisphenoid dorsally and the orbitosphenoid posteriorly and ventrally. The frontal’s sutures with the orbitosphenoid and ethmoid are obliterated in AMNH 185012 (Figs. 6, 14). In the ventroposterior pars orbitalis are a variable number of small to medium sized foramina, ranging from four in AMNH 185012 to nine in AMNH 28272 (right side). The bisected skull AMNH 28271 is the only specimen in which the internal connections of these foramina can be traced, and based on it, four categories of foramina are identified here. (1) Anterior opening of orbitotemporal canal (“1” in Fig. 15). All specimens consistently have a posterodorsalmost foramen that is directed posteriorly. Previous authors (e.g., Gregory 1910; McDowell 1958; MacPhee 1994) agree that this medium sized aperture is the anterior opening of the sinus canal (Parker 1886) or the orbitotemporal canal (Rougier et al. 1992; Wible et al. 2004), which in other placentals transmits the ramus superior of the stapedial artery and accompanying vein (Wible 1984, 1987). This aperture is called variously the supraorbital foramen (Gregory 1910:274), the sinus canal foramen (McDowell 1958), the cranio-orbital foramen (MacPhee 1994), and the anterior opening of the orbitotemporal canal (Wible and Gaudin 2004). The last term (“otc” in Figs. 14, 16) is preferred, because it is the best descriptor of the position and best reflects the homology of this structure across a broad spectrum of cynodonts (Rougier et al. 1992; Wible and Gaudin 2004). The identification of this foramen in Solenodon is confirmed by establishing continuity between the foramen and the orbitotemporal groove and canal on the endocranial surface of AMNH 28271 (“otg” and “otc” in Fig. 21C). AMNH 28272 reveals that the foramen is not entirely within the frontal; the orbitosphenoid forms most of the medial border (Fig. 16). The alisphenoid appears to contribute but merely overlies the frontal. (2) Ethmoidal foramina (“2a” and “2p” in Fig. 15). AMNH 28271 has two foramina that empty endocranially into a depression posterolateral to the cribriform plate and represent ethmoidal foramina. The larger posterodorsal foramen lays anteroventrally in a common depression with the orbitotemporal canal opening and is directed anteromedially into the skull, and the smaller anteroventral foramen is directed posteromedially into the skull and has a faint groove extending anteroventrally from it. Internally, the posterodorsal foramen opens posteromedial to the anteroventral foramen (“pef” and “aef” in Fig. 22). These same two ethmoidal foramina can be identified by 1/6/09 9:25:00 AM 340 Annals of Carnegie Museum Vol. 77 Fig. 15. Solenodon paradoxus, CM 18069, photograph of right orbit in oblique lateral view. Abbreviations: 1, anterior opening, orbitotemporal canal; 2a, anteroventral ethmoidal foramen; 2p, posterodorsal ethmoidal foramen; 3a, anterior frontal diploic vein foramen; 3p, posterior frontal diploic vein foramen; 4, supra-optic foramen; asc alisphenoid canal; ch, choanae; fo, foramen ovale; ham, left pterygoid hamulus; of, optic foramen; sbof, suboptic foramina; sof, sphenorbital fissure; spf, sphenopalatine foramen; tcf, transverse canal foramen. position and direction in the orbits of the remaining specimens (“aef” and “pef” in Figs. 14, 16, 19). In the juvenile AMNH 28272 (Figs. 16, 19), the anteroventral foramen is entirely within the frontal but the posterodorsal one is not; the orbitosphenoid contributes to the medial wall. AMNH 212912 differs from the other specimens in that the posterodorsal foramen is not in a common depression with the orbitotemporal canal opening. The dog also has two ethmoidal foramina with the larger posterodorsal one for the external ethmoidal artery and companion vein and the anteroventral one for the ethmoidal nerve (Evans 1993). Gregory (1910: fig. 18A2; see Fig. 1) identified only one ethmoidal foramen in AMNH 28272, the anteroventral ethmoidal foramen of this report; he appears to have labeled this foramen incorrectly as a venous foramen in another figure of the same specimen (1910: fig. 18A1; see Fig. 1). Gregory (1910: fig. 18A2; see Fig. 1) labeled the posteroventral ethmoidal foramen as the supra-optic foramen, a venous foramen. McDowell (1958: fig. 10B) correctly labeled two ethmoidal foramina; the only oddity is that the groove extending from the anteroventral foramen is directed anterodorsally, whereas it is anteroventral in the specimens studied here. MacPhee (1994: figs. 6 [p. 63], 8) identified one ethmoidal foramen in AMMH 35330, the posterodorsal foramen of this report; however, in another view of the same specimen (fig. 6 [p. 61]) he labeled a foramen more anteriorly positioned as the ethmoidal foramen. This foramen likely belongs to the third category discussed below. (3) Frontal diploic vein foramen (“3a” and “3p” in Fig. 15). MacPhee (1994: fig. 6) noted a third foramen situated anterolaterally in the same depression as the orbitotemporal canal opening (his cranio-orbital foramen) and Wible.indd 340 posterodorsal ethmoidal foramen (his ethmoidal foramen) in AMNH 35330 and identified it as the frontal diploic foramen. In the dog (Evans 1993), the frontal diploic vein is an emissary vein of the diploë of the frontal bone to the dorsal external ophthalmic vein occupying an unnamed foramen in the orbital surface of the postorbital process of the frontal (for incidence in other placentals, see Thewissen 1989). MacPhee’s identification is accepted, but there are two frontal diploic vein foramina directed dorsally into the substance of the frontal in the specimens studied here, anterior and posterior. The former is anterolateral to the anteroventral ethmoidal foramen and was misidentified as the ethmoidal foramen in AMNH 28272 by Gregory (1910: fig. 18A1; see Fig. 1); the latter corresponds to the foramen identified by MacPhee. CM 18069 and AMNH 28271, 28272 (right side), and 212912 have both anterior and posterior frontal diploic vein foramina (Fig. 15), although the posterior one is tiny in AMNH 28271 and the anterior one is tiny in AMNH 212912. AMNH 185012 has only the posterior foramen (“fdv” in Fig. 14), and AMNH 28272 (left side) only the anterior one. It was not possible to pass a probe through either foramen in the bisected skull AMNH 28271 in order to trace the endocranial connection; nevertheless, both foramina likely lead dorsally into a thick column of frontal bone that demarcates the rostral and middle cranial fossae (see below). In addition to the anterior and posterior foramina in AMNH 28272 (right side) are three small, dorsally directed foramina posterior to the anteroventral ethmoidal foramen that are identified here as middle frontal diploic vein foramina (Fig. 19); the left side has two such foramina immediately lateral to the anteroventral ethmoidal foramen. All of the frontal diploic vein foramina in AMNH 28272 are entirely within the frontal bone. Gregory (1910: fig. 18A2; see Fig. 1) labeled one of the middle frontal diploic vein foramina on the left side of AMNH 28272 as supra-ethmoid foramen, noting (p. 248) correctly that it “leads dorsad, between the inner and outer tables of the frontal.” (4) Supra-optic foramen (“4” in Fig. 15). Gregory (1910: fig. 18A2; see Fig. 1) labeled a foramen medial to the orbitotemporal canal opening (his sinus canal) in AMNH 28272 as the supra-optic foramen. He stated (p. 248) that it “runs downward and backward and joins the suboptic” foramen, which “runs downward and backward to the transverse sinus in the presphenoid.” However, the opening that Gregory labeled in AMNH 28272 is clearly the posterodorsal ethmoidal foramen of this report (Fig. 16). Nevertheless, the right side of the bisected skull AMNH 28271 does have a supra-optic foramen as defined by Gregory. The medium sized foramen is positioned immediately ventromedial to the posterodorsal ethmoidal foramen, and a probe passed through it reaches a transverse sinus in the presphenoid. The left side of AMNH 28271 has two tiny foramina where the supra-optic foramen occurs on the right. CM 18069 has a supra-optic foramen on both sides (Fig. 15). AMNH 28272 has a small foramen within the frontal anteromedial to the posterodorsal ethmoidal foramen that likely is 1/6/09 9:25:01 AM 2008 Wible—On the Cranial Osteology of Solenodon paradoxus 341 Fig. 16.—Solenodon paradoxus, AMNH 28272, photograph and line drawing of braincase in oblique right lateral view. Palatine is entirely absent from specimen, whereas premaxilla and most of maxilla and nasal are preserved separately. Scale = 5 mm. Abbreviations: aef, anteroventral ethmoidal foramen; as, alisphenoid; asc, alisphenoid canal; bs, basisphenoid; fr, frontal; gf, glenoid fossa; mx, maxilla (broken); mxfc, facet for maxilla on frontal; na, nasal (broken); nt, nasoturbinate (ethmoid part); of, optic foramen; oleth, orbital lamina of ethmoid; os orbitosphenoid; otc + fdv, anterior opening, orbitotemporal canal and posterior frontal diploic vein foramen; pa, parietal; pef, posterior ethmoidal foramen; pet, petrosal; pf, piriform fenestra; pl, primary lamina (for ethmoturbinate I and II); ppe, perpendicular plate of ethmoid; ps, presphenoid; psw, presphenoid wing (of opposite side); pt, pterygoid; rm, recessus maxillaris; sof, sphenorbital fissure; sq, squamosal; tcf, transverse canal foramen; tl, transverse lamina (of opposite side); tleth, tectorial lamina of ethmoid; v, vomer. a supra-optic foramen (“s-of” in Fig. 19). In light of the sutural relations and position of the supra-optic foramen in AMNH 28272, it is doubtful that the supra-optic foramen in AMNH 28271 and CM 18069 are entirely within the frontal; they are more likely within the orbitosphenoid or between the orbitosphenoid and frontal. AMNH 185012 and 212912 do not have comparable foramina. The internal surface of the frontal can be studied in the bisected skull AMNH 28271 (Figs. 20, 21A, C) and through the foramen magnum in the juvenile AMNH 28272, with only the latter providing sutural information. AMNH 28272 (see Fig. 21C) reveals that the frontal has only a small contribution in the posterolateral roof and posterodorsal wall of the nasal cavity, with the remaining posterior roof and wall formed by the underlying ethmoid. This internal exposure of frontal corresponds to the lateral half of the triangular maxillary process on the exterior. The frontals form the roof and lateral walls of the rostral cranial fossa in AMNH 28272, with the underlying ethmoid completing that space ventrally. The frontals also form the roof Wible.indd 341 and dorsolateral walls of the anteriormost middle cranial fossa, with the overlying parietals forming the roof and lateral walls posterior to the frontals. The orbitosphenoids form the ventrolateral walls of the anteriormost middle cranial fossa, with the frontal underlying the orbitosphenoid throughout most of their suture. A frontal sinus appears to be lacking. Along the midline roof in the rostral cranial fossa in AMNH 28271 and 28272 is a broad crest for the attachment of the falx cerebri, the crista frontalis, which anteriorly turns ventrally into a short crest at the anterodorsal aspect of the cribriform plate. Perpendicular to the crista frontalis is a more pronounced crest on the frontal demarcating the rostral and middle cranial fossae, which presumably lies opposite the circular fissure, which separates the olfactory bulb from the cerebral hemisphere (“ar” in Fig. 21C). This is the annular ridge of the frontal of Rowe et al. (2005). Occupying the space between the inner and outer table of the frontal within the annular ridge is the frontal diploic vein, based on the position and 1/6/09 9:25:04 AM 342 Annals of Carnegie Museum Vol. 77 direction of the frontal diploic vein foramina in the orbit. Also, a large canal for the frontal diploic vein is visible just off the midline in the braincase roof in the bisected skull AMNH 28271 (see Fig. 21C), suggesting that this vein extends the height of the annular ridge and likely communicates with its fellow of the opposite side. Asymmetrically arranged foramina on the annular ridge presumably drain from the endocranium into the frontal diploic vein. Parietal (“pa” in figures) The paired parietal forms the bulk of the braincase roof and lateral walls. AMNH 28272 is the only specimen with sutures delimiting the entire parietal (Fig. 5); in AMNH 185012 the sutures with the interparietals are obliterating (“ip” in Fig. 2). The external surface is described based on AMNH 185012 (Fig. 2); differences from the other specimens are noted below. At the midline, the parietal comprises more than 25% of total skull length; at its greatest length, the parietal is 35% of total skull length. At the level of the glenoid fossa, the parietals comprise more than 66% of skull width. The parietals meet on the midline and have fairly straight contacts with their other neighbors, except posteriorly. Anteriorly, the parietal overlaps the frontal at a roughly transverse suture, except for a midline U-shaped incursion of the frontals (see above). On the lateral border, based on AMNH 28272, the parietal has a straight suture with the alisphenoid anteriorly and underlies the squamosal posteriorly (“as” and “sq” in Fig. 16). The anterior half of the alisphenoid suture is plane and the posterior half is foliate; the parietosquamosal suture is curved with the parietal the concave member. Based on AMNH 185012, between the back of the squamosal and the front of the supraoccipital (“so” in Fig. 2) is an interval where the parietal forms the entire braincase roof, its posterolateral edge forming the nuchal crest (“nc” in Fig. 34) and articulating with the supraoccipital and mastoid exposure of the petrosal (left side only) on the occiput (“me” in Fig. 34). Posteriorly (Fig. 2), the parietal overlaps the supraoccipital and the interparietal at a roughly L-shaped suture. At the level of the glenoid fossa, the midline parietal suture is fairly flat in AMNH 185012, but is slightly raised anteriorly and posteriorly as a weak sagittal crest (“sc” in Fig. 2). A more pronounced sagittal crest runs the extent of the midline parietal suture in the adults CM 18069 and AMNH 28271 and 212912 (Figs. 4, 7). A sagittal crest is lacking in the juvenile AMNH 28272 (Fig. 5). The parietal in all specimens except AMNH 28272 has a distinct orbitotemporal crest that curves anterodorsally from the front of the parietosquamosal suture (“otcr” in Fig. 6). In the posterior parietosquamosal suture are located several posterodorsally directed foramina for rami temporales (“rt” in Figs. 2, 6), which carry blood to and from the temporalis muscle based on MPIH 6863 and lead into posterodorsally directed sulci on the parietal. AMNH 28272 has two per Wible.indd 342 side in the suture (Fig. 5); AMNH 185012 has one in the left suture and three in the right (Fig. 2). More of these foramina are located entirely within the squamosal near to those in the suture. Consequently, it is not possible to identify the bony relationships of the rami temporales foramina in the adults AMNH 28271, 212912, and CM 18069, because the parietosquamosal suture is obliterated (Fig. 7). The juvenile AMNH 185012 and the adults also have a variable number of asymmetrically positioned tiny parietal foramina, emissary foramina along the midline (Fig. 2). Nearly the entire endocranial surface of the parietal is visible through the foramen magnum and piriform fenestra in AMNH 28272. The parietal is the major element of the roof and lateral walls of the middle cranial fossa and also contributes to the roof and walls of the caudal cranial fossa (see Fig. 21C). In the anterior part of the middle cranial fossa, the parietal overlaps the frontal in the roof and upper lateral wall and the orbitosphenoid in the lower lateral wall. Posterior to the orbitosphenoid, the parietal forms the lateral wall, overlying the alisphenoid, which is confined largely to the floor. At roughly a right angle to the alisphenoid contact, the parietal contacts the squamosal at a plane suture (much of this suture is preserved in AMNH 28271); the squamosal contributes only a narrow strip to the wall of the middle cranial fossa anterior to the petrosal. Posterodorsal to the squamosal, the parietal overlaps the dorsal border of the petrosal (“pet” in Fig. 21C), contributing to the upper lateral wall of the caudal cranial fossa (this suture is preserved in AMNH 28271). The parietal overlaps the supraoccipital posteroventrally and the interparietal posterodorsally. Dorsal to and in line with the crista petrosa (“crp” in Fig. 21C) is a low eminence on the parietal that demarcates the middle and caudal cranial fossae and is attachment for the tentorium cerebelli, which contains the transverse sinus, the main distributary of the dorsal sagittal sinus. This eminence is less distinct than the annular ridge on the endocranial surface of the frontal in AMNH 28271 and 28272. The endocranial surface of the parietal has several welldeveloped grooves associated with arteries and veins, described here based on AMNH 28271. Spanning 11 mm in the wall of the middle cranial fossa is the orbitotemporal groove for the ramus superior and accompanying veins, roughly 1 mm in width (“otg” in Fig. 21C). Posteriorly, the orbitotemporal groove begins at the anterodorsal corner of the petrosal, where based on AMNH 28272 the squamosal forms a narrow segment of the wall of the initial groove; the remainder of the groove is in the parietal. The groove arches anteroventrally and disappears at the posterior edge of the orbitosphenoid. Anterior to this is a short orbitotemporal canal, at least initially between the parietal and orbitosphenoid, which leads to the anterior opening of the orbitotemporal canal between the frontal and orbitosphenoid in the orbit (Fig. 14). Spanning 5 mm in the wall of the caudal cranial fossa is the sulcus for the sigmoid sinus, roughly 2 mm in width (“sss” in Fig. 21C). For the anterior 3 mm, the sulcus is principally on the 1/6/09 9:25:04 AM 2008 Wible—On the Cranial Osteology of Solenodon paradoxus parietal, with the petrosal forming the ventral quarter; this relationship is reversed posteriorly. The part of the sulcus on the parietal is directed posteroventrally; at the posterodorsal corner of the petrosal the sulcus turns ventrally toward the condyloid canals in the exoccipital (“eo” in Fig. 21C). At the bend the supraoccipital contributes to the posteriormost part of the sulcus and the petrosal the remainder. Extending anteriorly from the sulcus for the sigmoid sinus is a 2 mm long canal between the parietal and petrosal for the prootic sinus (“ecps” in Fig. 21C), the other major distributary of the transverse sinus, that leaves the skull primarily via the postglenoid foramen as the postglenoid vein. Anterior to the canal, a sulcus for the prootic sinus in the squamosal runs anteroventrally toward the postglenoid foramen (“sps” in Fig. 21C). Interparietal (“ip” in figures) As noted by Gregory (1910:242), the juvenile AMNH 28272 “possesses a pair of good sized interparietal bones separated by a median but slightly asymmetrical suture, and partly overlaid by the parietals” (Figs. 1, 5). The juvenile AMNH 185012 also preserves the interparietals as separate elements (Fig. 2), but in the adult specimens the interparietals are fused with each other and with their neighbors (Fig. 4). In dorsal view (Fig. 5), the right interparietal of AMNH 28272 is essentially the shape of a thumbnail, with the curved part directed anteriorly. The base, posterior side, has a serrated suture with the supraoccipital, and the right and anterior sides are overlaid by the right parietal. The midline interparietal suture, as noted by Gregory, is asymmetrical, with the suture listing to the right anteriorly and posteriorly but on the midline in between. Considerably more of the left interparietal is currently exposed along the supraoccipital margin, but most of the extra exposure sports a facet for a missing part of the left parietal. Damage to the left parietal postdates Gregory because his illustration (1910: fig. 18A1; see Fig. 1) of the left interparietal resembles the right one. The interparietals in AMNH 185012 are also in the shape of thumbnails (Fig. 2). Sutures with the supraoccipital are present, but those with the parietals are obliterating, more so along the anterior sides than the lateral. AMNH 28272 has no sagittal crest along the midline interparietal suture (Fig. 5), but the remaining specimens do (Figs. 2, 4, 7). AMNH 28272 and 185012 lack any foramina in the interparietal (Figs. 2, 5), whereas the adults AMNH 28271 and 212912 have several small, asymmetrically arranged foramina; CM 18069 has several foramina in the position where the interparietal-supraoccipital suture was likely located (Fig. 4). The endocranial surface of the interparietals of AMNH 28272 is visible through the foramen magnum. The interparietals form most of the roof of the caudal cranial fossa, and the endocranial surface is considerably larger anteriorly and laterally than the external exposure. Each Wible.indd 343 343 interparietal is roughly quadrangular, but only the medial side is straight, the others being convexly curved. A distinct depression for the vermis of the cerebellum occupies the posteromedial half of the right and left interparietals and continues posteriorly onto the supraoccipital. This depression is much less distinct in the adult AMNH 28271. Pterygoid (“pt” in figures) The paired pterygoid is not fully delimited as a separate element from the basi- and alisphenoid in any specimen. The juvenile AMNH 28272 and to a lesser extent AMNH 185012 have seams that are interpreted as marking the line of fusion with the basi- and alisphenoid along the anteromedial, medial, posterior, and posterolateral borders of the pterygoid (“>” in Fig. 19). However, the anterolateral borders with the alisphenoid are not indicated. The pterygoid is described here based on these seams. The serially sectioned juvenile MPIH 6863 has sections preserving only the posterior part of the pterygoid; this bone is for the most part independent of the overlying basi- and alisphenoids, but some sections do show fusion. The pterygoid is a long, narrow element lying ventral to the sphenoid complex, separated by the pre- and basisphenoid from the pterygoid of the opposite side (Fig. 19). Posteriorly, the main axis of the pterygoid is in the same plane as the skull base; anteriorly the main axis is perpendicular to the skull base, forming the parasagittal posterolateral wall of the basipharyngeal canal behind the palatine. The transition between these two parts is gradual rather than abrupt. The horizontal part of the pterygoid is the caudal process, and the perpendicular part is the entopterygoid process, at the ventral extent of which is the pterygoid hamulus (“cpp”, “enp”, and “ham” in Fig. 19). The anterior face of the entopterygoid process contacts the back of the perpendicular process of the palatine and a suture indicating this is preserved both medially within the basipharyngeal canal and laterally within the orbital floor only in AMNH 185012 (Figs. 11, 14). Only part of the medial pterygopalatine suture is preserved in AMNH 212912 and CM 18069, and the suture is obliterated in AMNH 28271. The anteromedial base of the entopterygoid process is separated from the overlying presphenoid by a suture in the juveniles AMNH 28272 and 185012 (Figs. 11, 19), but these are fused in the adults. The entopterygoid process approximates but does not contact the vomer in AMNH 28272 (Fig. 19), whereas sutural contact of these elements is preserved in AMNH 185012 (Fig. 11), 212912, and CM 18069. The entopterygoid process of the juvenile AMNH 28272 differs from the remaining specimens in that it projects only slightly more ventrally than the caudal process (Fig. 19); that is, there is not as great a height differential between the two as occurs in the older skulls (Figs. 6, 7, 14). In addition to being relatively shorter, the entopterygoid process of AMNH 28272 is mediolaterally thicker except at its ventral margin (Fig. 19) and not the laminar 1/6/09 9:25:04 AM 344 Annals of Carnegie Museum Vol. 77 Fig. 17.—Solenodon paradoxus, AMNH 28272, photograph and line drawing of braincase (nasal cavity) in anterior view. Both sides have been damaged with most structures more complete on the specimen’s right side, ethmoturbinal I being an exception. Damage to the septum frontomaxillare on the left side exposes the recessus frontalis. Abbreviations: ec 1, ectoturbinal 1; ec 2, ectoturbinal 2; et I, ethmoturbinal I; et II, ethmoturbinal II; et III, ethmoturbinal III; fnf, fundus of nasal fossa; nt, nasoturbinate (ethmoid part); pl, primary lamina of ethmoturbinal I and II; ppe, perpendicular plate of ethmoid; rf, recessus frontalis; rm, recessus maxillaris; sfm, septum frontomaxillare; tl, transverse lamina; v, vomer (broken). Wible.indd 344 1/6/09 9:25:09 AM 2008 Wible—On the Cranial Osteology of Solenodon paradoxus plate that occurs in the older skulls (Figs. 11, 12). The two millimeter long ventral edge of the entopterygoid process in AMNH 28272 is the pterygoid hamulus. This edge is uniformly thin mediolaterally on the left side, but twice as wide anteriorly as posteriorly on the right side (Fig. 19). The pterygoid hamulus is damaged bilaterally in AMNH 185012 and on the right side of CM 18069 (Fig. 12). In AMNH 212912 (Fig. 12), the hamulus is oriented obliquely anterolaterally, with a thickened ventral border some three millimeters in length; on the right side of CM 18069, the thickened part of the ventral edge is half as long and straight (Fig. 12); and in AMNH 28271, the ventral border is not thickened at all, but has a slight medial inflection at its posterior edge. Posterior to the level of the hamulus, the caudal process begins the gradual transition from a near vertical element to a near horizontal one. In the seam between the medial edge of the caudal process and the basisphenoid in AMNH 28272 are two foramina: an anterior one slightly posterior to the level of the foramen ovale (“fo” in Fig. 19) and a posterior one medial to the posterior opening of the pterygoid canal (vidian canal) (“pc” in Fig. 19). The older specimens have a variable number (two to six) of similarly situated foramina. In AMNH 28272 these foramina can be traced into the basisphenoid’s transverse canal (“tsc” in “bs” in Fig. 21C), and veins occur in similar foramina in the sectioned juvenile MPIH 6863. The posterior border of the caudal process in AMNH 28272 nearly reaches as far posterolaterally as does the overlying basisphenoid, falling just short of contacting the anterior pole of the promontorium and contributing to the border of the piriform fenestra (“pr” and “pf” in Fig. 19). In the posterolateral margin of the caudal process is the entrance into the pterygoid canal (Fig. 19): the caudal process forming the floor and the basisphenoid the roof as in the sectioned juvenile MPIH 6863. Anterior to the pterygoid canal opening, a faint seam delimits the caudal process from the overlying tympanic process of the alisphenoid (“tpas” in Fig. 19), but anterior to the level of the foramen ovale, the pterygoid and alisphenoid are seamlessly fused (not visible in Fig. 19). Ethmoid (“eth” in figures) The unpaired ethmoid forms the back of the nasal cavity and the front of the rostral cranial fossa. With the exception of a small triangular exposure in the orbit, based on AMNH 28272 (Fig. 16), the ethmoid is hidden in external view. Aspects of the ethmoid can be studied in the bisected adult and partially disarticulated juvenile skulls, AMNH 28271 and 28272. The ethmoid consists of four parts: a median perpendicular plate or lamina, a cribriform plate, and two lateral masses covered by the external lamina of the ethmoid; the four ethmoturbinates, two ectoturbinates, and the ethmoid part of the nasoturbinate are attached to the lateral masses and/or cribriform plate. Wible.indd 345 345 The major elements of the nasal septum are the perpendicular plate of the ethmoid behind and the cartilaginous nasal septum in front. The proportions of these two elements differ dramatically in the two specimens. In the younger AMNH 28272, the perpendicular plate reaches forward to the level of the maxillary process of the frontal opposite dP5 (“ppe” in Figs. 16, 18). In contrast, in AMNH 28271 more of the cartilaginous nasal septum is ossified (and sutures do not delimit the contributing elements), presumably with the ethmoid reaching I2 (Fig. 20). In the former, AMNH 28272 (Fig. 16), the perpendicular plate stretches between the posterior nasal cavity roof, which is the external laminae of the ethmoid (the tectorial lamina or tectum nasi), and the posterior sagittal part of the vomer (Fig. 17). Based on AMNH 28271, which lacks sutural information, the perpendicular plate also likely contacts the nasals dorsally and the anterior sagittal part of the vomer and the septal processes of the premaxillae ventrally (Fig. 20). The cribriform plate is a deeply concave, sieve-like partition between the posterior nasal cavity and rostral cranial fossa (“cpl” in Figs. 22B, C, 23). It is angled such that its dorsal margin is anterior to its ventral margin. Approximately 300 variably sized foramina perforate the plate on the right and left sides in AMNH 28271 (Fig. 23) and transmit olfactory nerve bundles. A broad central ridge (“cr” in Fig. 23) separates the right and left ethmoidal fossae, which housed the olfactory bulbs in life. The ridge is pierced by numerous foramina but has no crista galli in all specimens exposing this surface (CM 18069 is unknown because dried meninges cover the plate). Within each ethmoidal fossa, the cribriform foramina are arranged in cauliflower-like clusters, which surround the attachment of the ethmoturbinals (see below) as reported in other placentals, e.g., dog (Evans 1993), Monodelphis Burnett, 1830 (Rowe et al. 2005), and Pteropus (Giannini et al. 2006). AMNH 28272 is the only specimen to preserve sutures delimiting the ethmoid in the rostral cranial fossa, but the view through the foramen magnum does not provide access to the entire circumference of the bone. The dorsal and lateral sutures with the frontal follow closely the outer margin of the cribriform plate (see Fig. 21C). Regarding the ventral suture, only the midline area is visible. It shows a broad, non-cribriform eminence of the ethmoid in contact with the presphenoid. The posterior face of this eminence faces the middle cranial fossa. In AMNH 28271, a shallow, horizontal sulcus (“hs” in Fig. 23) near the outer margin of the cribriform plate demarcates two major clusters of foramina, a larger anterodorsal and smaller posteroventral. In the anterodorsal cluster are the foramina for the nasoturbinate and the two ectoturbinals (“nt”, “ec 1”, and “ec 2” in Fig. 23) as well as the cribroethmoidal foramen for the passage of the ethmoidal nerves (“cef” in Fig. 23); in the posteroventral cluster are the foramina for ethmoturbinal II, III, and IV (“et II”, “et III’, and “et IV” in Fig. 23); and sandwiched in between the two clusters are foramina for ethmoturbinal I (“et I” in Fig. 23). At the outer 1/6/09 9:25:10 AM 346 Annals of Carnegie Museum Vol. 77 Fig. 18.—Solenodon paradoxus, AMNH 28272 photograph and line drawing of braincase in ventral view. Palatine is absent from specimen and rostrum is preserved separately. Nasal cavity is damaged on both sides, but more so on the specimen’s left side (see Fig. 17). Abbreviations: as, alisphenoid; bo, basioccipital; bs, basisphenoid; e, ectotympanic, ec 1, ectoturbinal 1; ec 2, ectoturbinal 2; egp, entoglenoid process; eo, exoccipital; eth, ethmoid; fr, frontal; gri, groove for ramus inferior; na, nasal (broken); nt, nasoturbinate (ethmoid part); oc, occipital condyle; oleth, orbital lamina of ethmoid; os, orbitosphenoid; pa, parietal; pf, piriform fenestra; pl, primary lamina of ethmoturbinal I and II; ppe, perpendicular plate of ethmoid; pr, promontorium of petrosal; ps, presphenoid; pt, pterygoid; rm, recessus maxillaris; so, supraoccipital; sq, squamosal; tl, transverse lamina; tpas, tympanic process of alisphenoid; v, vomer (broken). margin of the cribriform plate, the horizontal sulcus turns posteroventromedially for 5 mm and ends at two foramina posterolateral to the cribriform plate (“aef” and “pef” in Fig. 22). The smaller anterolateral one connects with the anteroventral ethmoidal foramen in the orbit, and the larger posteromedial one with the posterodorsal ethmoidal foramen. Unfortunately, the positional relationship of these endocranial foramina to the frontoethmoidal or sphenoethmoidal suture cannot be ascertained. As viewed in AMNH 28272, the outer covering of the lateral masses is the external lamina, which includes a roof or tectorial lamina (“tleth” in Fig. 16), lateral wall or orbital lamina (“oleth” in Fig. 16), and a floor or basal lamina, Wible.indd 346 which is fused to the vomerine wing to form the transverse lamina (“tl” in Fig. 16). Dorsal to the tectorial lamina are the posterior parts of the nasal and maxilla and the maxillary processes of the frontals and ventral to the roof is the perpendicular plate. Most of the orbital lamina is covered by the frontal with a narrow strip along the anterior margin covered by the maxilla. However, there is a triangular exposure of the orbital lamina in the orbital wall between the sphenopalatine and optic foramina in AMNH 28272 (Figs. 1, 16, 19). The short, vertical anterior side of the triangle is covered by the maxilla; the long, horizontal ventral side is covered by the palatine; and the long, inclined dorsal side is covered by the frontal; the posterior tip of the 1/6/09 9:25:14 AM 2008 Wible—On the Cranial Osteology of Solenodon paradoxus 347 Fig. 19.—Solenodon paradoxus, AMNH 28272, photograph of braincase in oblique right ventral view. Carat points outline the suture separating the right pterygoid and presphenoid and the seams separating the right pterygoid from the basisphenoid and alisphenoid. Scale = 5 mm. Abbreviations: acc, alicochlear commissure; aef, anteroventral ethmoidal foramen; as, alisphenoid; asc, alisphenoid canal; bs, basisphenoid; cpc, craniopharyngeal canal; cpp, caudal process of pterygoid; enp, entopterygoid process; ew, epitympanic wing of petrosal; fr, frontal; gf, glenoid fossa; ham, pterygoid hamulus; mxfc, facet for maxilla on frontal; of, optic foramen; oleth, orbital lamina of ethmoid; orf, oribital fissure; os, orbitosphenoid; otc + fdv, anterior opening, orbitotemporal canal and posterior frontal diploic vein foramen; pa, parietal; pc, posterior opening, pterygoid canal; pef, posterodorsal ethmoidal foramen; pf, piriform fenestra; ps, presphenoid; psw, presphenoid wing; pt, pterygoid; rtp, rostral tympanic process of petrosal; sbof, suboptic foramen; s-of, supraoptic foramen; sq, squamosal; tcf, transverse canal foramen; tl, transverse lamina; tpas, tympanic process of alisphenoid; v, vomer (broken). triangle has a plane contact with the orbitosphenoid (Fig. 1). Immediately ventromedial to the orbital exposure of the ethmoid is the transverse lamina (Fig. 16), which is concealed in external view by the missing palatine. In anterior view, two distinct spaces are visible on the right ethmoid of AMNH 28272; the larger medial space is the fundus of the nasal fossa or olfactory recess (“fnf” in Fig. 17), which contains the ethmoturbinals and ends posteriorly at the cribriform plate, and the smaller, crescentic lateral space is a dead end diverticulum off the main nasal passage (“rm” in Fig. 17). The latter space is part of the recessus lateralis of the pars intermedia of the nasal capsule, which lies between the pars anterior and pars posterior (Smith and Rossie 2006); the pars posterior includes the olfactory recess and the pars anterior lies between the external nasal aperture and olfactory recess. The recessus lateralis is often subdivided in therians by a septum frontomaxillare into a recessus maxillaris ventrally and a recessus frontalis dorsally (Smith and Rossie 2006). The crescentic lateral space in AMNH 28272 is the recessus maxillaris (maxillary recess). The ethmoid forms most of the boundaries of the recessus maxillaris, with the maxilla contributing the anterior part of the lateral wall (“rm” in Fig. 9). The medial wall of the recessus maxillaris has several longitudinal Wible.indd 347 depressions and rounded prominences (Fig. 16), the former marking the attachments of ethmoturbinals and ectoturbinals. The largest of these prominences is centrally located and is delimited by the attachment of ectoturbinal 2 above and the primary lamina of ethmoturbinal I and II below (“pl” in Fig. 17). At the anterior end of this prominence is a distinct, curved, lip-shaped thickening that connects the anterior base of ectoturbinal 1 to the primary lamina (Fig. 17). Part of the dorsal wall between the recessus maxillaris and the fundus of the nasal fossa is damaged on the left side, revealing more of a third space between the ethmoid part of the nasoturbinate and the recessus maxillaris; this is the recessus frontalis (“rf” in Fig. 17). Consequently, the wall between the recessus maxillaris and recessus frontalis is the septum frontomaxillaris (“sfm” in Fig. 17). The recessus frontalis houses the two ectoturbinals (Fig. 17). In AMNH 28272, the base of the ectoturbinal 1 is thick, extends medially and slightly ventrally, and thins to a scroll directed dorsally and slightly laterally; the base of the ectoturbinal 2 is thin, thickens medially, and then thins to dorsolateral and ventrolateral scrolls. Two ectoturbinals are present in AMNH 28271 (although not in the figures), but the base of ectoturbinal 1 is thin, in contrast to the 1/6/09 9:25:15 AM 348 Annals of Carnegie Museum Vol. 77 Fig. 20.—Solenodon paradoxus, AMNH 28271, photographs of left and right sides of bisected skull in medial views. Bisection occurred off the midline such that the right side includes the osseous nasal septum; the cartilaginous nasal septum above the premaxilla is not preserved. Posterior to the osseous nasal septum the posterior part of ethmoturbinal III and all of ethmoturbinal IV are visible. The left side is broken in two pieces; an oblique seam is visible at the break directed anterodorsally from just posterior to the penultimate premolar. Scale = 10 mm. condition in AMNH 28272. The fundus of the nasal fossa contains the ethmoid part of the nasoturbinate and the four ethmoturbinals (Fig. 17). In identifying ethmoturbinals, followed here is the terminology of Smith and Rossie (2006), which includes a useful table of synonyms with authors such as Moore (1981) and Maier (1993). The ethmoid part of the nasoturbinate (endoturbinate I of Moore 1981) is completely preserved on the left side of AMNH 28271 (Fig. 21B). It arises from the tectorial lamina and is continuous anteriorly with the nasoturbinate crest on the nasal. It is a simple ridge, low anteriorly and posteriorly, and with a triangular prominence opposite P5 and M1 that is partially hidden by ethmoturbinal I in medial view. The ethmoid part of the nasoturbinate extends to the posterior wall of the nasal fundus. The triangular prominence of the ethmoid part of the nasoturbinate is preserved on the left side of AMNH 28272 (Fig. 17). The triangle’s anterior side is damaged or incompletely ossified, and the posterior side is slightly thickened. The triangle extends roughly a third of the way down the nasal fundus, medial to ectoturbinal 1. Ethmoturbinal I and II are nearly completely preserved on the left side of AMNH 28271 (Fig. 21B). They arise from a common base, the primary lamina, opposite M2, that is very thick, directly slightly dorsomedially from the horizontal, and divides into two scrolls, both of which Wible.indd 348 extend to the posterior wall of the nasal fundus. The longer dorsal scroll, ethmoturbinal I, is most prominent opposite P5 and M2 and the ventral scroll, ethmoturbinal II, opposite M2 and M3. Both scrolls are relatively simple and concave ventromedially. The base of the ethmoturbinal I is thickened and divides the scroll into anterior and posterior halves, with the tip of the anterior half overlying the ventral nasal concha or maxilloturbinate and the posterior half overlying ethmoturbinal II. Ethmoturbinal I and II are preserved incompletely and completely, respectively, on both sides of AMNH 28272 (Fig. 17). Ethmoturbinal III is preserved bilaterally in AMNH 28271, but only the anterior part is visible on the left side (Fig. 21B) and the posterior part on the right (Fig. 20). It arises from the orbital lamina slightly posterior and ventral to the base of ethmoturbinal II, opposite the back of M2. The ventral prominence of its scroll extends from the level of M2 to the minor palatine foramen and it contacts the posterior wall of the nasal fundus behind the level of that foramen. Ethmoturbinal III is also preserved bilaterally in AMNH 28272, but only its anteriormost aspect is visible (Fig. 17). Ethmoturbinal IV can only be seen in AMNH 28271. On the right side (Fig. 20), the ventral prominence of its scroll extends from the level of the sphenopalatine to the optic foramen. Its posterodorsal border contacts the posterior wall of the nasal fundus. The narrow space posterior to 1/6/09 9:25:16 AM 2008 Wible—On the Cranial Osteology of Solenodon paradoxus 349 Fig. 21.—Solenodon paradoxus, AMNH 28271, left side of bisected skull in medial view. A, shaded drawing; B, line drawing of nasal cavity; C, line drawing of cranial cavity. Note specimen is broken in nasal cavity posterior to P4. Dashed lines in cranial cavity are sutures based on AMNH 28272; numbers 1 and 2 refer to foramina that transmit the postglenoid vein to the postglenoid foramen on the skull base. Abbreviations: ar, annular ridge; as, alisphenoid; av, aqueductus vestibuli; bs, basisphenoid; C, upper canine; ccp, conchal crest of premaxilla; ch, choanae; coca, condyloid canals; cpl, cribriform plate; crp, crista petrosa; ecps, endocranial canal for prootic sinus; eff, ethmoidal foramina; enpc, entopterygoid crest; eo, exoccipital; et I, ethmoturbinal I; et II, ethmoturbinal II; et III, ethmoturbinal III; et IV + sphf, membrane covering space for ethmoturbinal IV and sphenoidal fossa; eth, ethmoid; fac facial canal; fai, foramen acusticum inferius; fdv, frontal diploic vein; fo, foramen ovale; fr, frontal; ham, pterygoid hamulus; hf, hypoglossal foramen; I2, upper second incisor; js jugum sphenoidale; M1, upper first molar; mt, maxilloturbinate; nt, nasoturbinate; oev, occipital emissary vein; op, os proboscidis; os, orbitosphenoid; otc, orbitotemporal canal; otg, orbitotemporal groove; P4, upper penultimate premolar; pa, parietal; pet, petrosal; ps, presphenoid; rt, foramen for ramus temporalis; saf, subarcuate fossa; so, supraoccipital; sof, sphenorbital fissure; spf, sphenopalatine foramen; spp, septal process of premaxilla; sps, sulcus for prootic sinus; sq, squamosal; sss, sulcus for sigmoid sinus; sva, superior vestibular area; tl, transverse lamina; tsc, transverse sinus canal. Wible.indd 349 1/6/09 9:25:18 AM 350 Annals of Carnegie Museum Vol. 77 Fig. 22.—Solenodon paradoxus, AMNH 28271, photograph of posterior part of left half of bisected skull in oblique medial view. Scale = 5 mm. Abbreviations: ace, anterior crus of ectotympanic; aef, anteroventral ethmoidal foramen; apf, accessory palatine foramen; ar, annular ridge; asc, alisphenoid canal; av, aqueductus vestibuli; cpl, cribriform plate; et IV + sphf, membrane covering space for ethmoturbinal IV and sphenoidal fossa; fo, foramen ovale; fpgv, endocranial foramen for postglenoid vein; gica, faint endocranial groove for internal carotid artery; hyf, hypophyseal fossa; js, jugum sphenoidale; mapf, major palatine foramen; of, optic foramen; pf, piriform fenestra; saf, subarcuate fossa; sof, sphenorbital fissure; spf, sphenopalatine foramen. ethmoturbinal IV is the sphenoidal fossa. On the left side it is hidden by a connective tissue septum separating the left and right sides (“et IV + sphf” in Fig. 21B). Vomer (“v” in figures) The unpaired vomer extends nearly the length of the nasal cavity and through the roof of the choanae into the anterior part of the basipharyngeal canal. The vomer is described (e.g., Evans 1993) as having sagittal and horizontal parts, with the latter at right angles to the former. In the juvenile AMNH 28272, the sagittal part is delimited from its neighbors by sutures anteriorly and posteriorly (“llv” in Fig. 9), but the horizontal part is fused to the ethmoid to form the transverse lamina separating the nasal fundus from the nasopharyngeal meatus (“tl” in Figs. 16, 18). In AMNH 185012, 212912, and CM 18069 the posterior sagittal part in the basipharyngeal canal is delimited (Figs. 11, 12). AMNH 28272 preserves the vomer in three broken pieces. Attached to the right and left premaxillae and maxillae are two pieces 10 mm in length (between C and dP5) of the anterior sagittal part of the vomer (Fig. 9). These two pieces represent the right and left lateral laminae of the vomer, which when rearticulated ventrally at their base on the midline between them form the V-shaped sulcus septi nasi for the perpendicular plate of the ethmoid. The notch between the anterior tips of the two laminae is the incisive incisure. The third piece of vomer is attached to the floors of the posterior nasal cavity and anterior braincase and includes the posterior sagittal and horizontal parts. The front of the posterior sagittal part is broken and at least a 6 mm section in front of the break is missing beneath the perpendicular plate of the ethmoid (Fig. 18); in addition there are longitudinal cracks and a narrow wedge of bone missing Wible.indd 350 posteriorly along the midline (Fig. 19). In ventral view (Fig. 18), the posterior sagittal part has a midline rodshaped eminence with narrow lateral wings that posteriorly in the basipharyngeal canal would have contacted the perpendicular plates of the palatines (see Fig. 11). Posteriorly, the posterior sagittal part extends just over a millimeter ventral to the presphenoid and sends narrow, sharp lateral processes off more posteriorly, with the notch between those processes being the sphenoidal incisure (Fig. 18). The lateral laminae of the posterior sagittal part are visible in anterior view (Fig. 17); the sulcus septi nasi between them is distinctly U-shaped. Extending laterally from all but the posterior five mm of the posterior sagittal part are the vomerine wings or alae, the horizontal part. It is only near the midline that the wings are horizontal, because the bulk of the wing angles ventrolaterally at roughly 30°. The vomerine wings are fused seamlessly with the external laminae of the ethmoid forming the transverse lamina. Roux (1947) reported the same condition in the adult shrew Suncus orangiae (Roberts, 1924) and in embryos the vomer was confined to the floor of the posterior nasal cavity. In light of this and the general morphology of the vomer in other placentals (e.g., dog, Evans 1993; horse, Sisson 1910), the vomerine wings in AMNH 28272 are reconstructed in the floor of the posterior nasal cavity and the ethmoid in the lateral wall of the nasal cavity, part of which is exposed externally in the orbit (also suggested by Saban 1956:219). In contrast, in Gregory’s (1910) illustration of AMNH 28272 (Fig. 1), he identified the orbital exposure of the lateral nasal cavity wall as the vomerine wing. In the three intact skulls, CM 18069 and AMNH 185012 and 212912, the posterior sagittal part of the vomer exposed in the basipharyngeal canal is variable. It is flat in CM 18069, with a rounded eminence that has a 1/6/09 9:25:19 AM 2008 Wible—On the Cranial Osteology of Solenodon paradoxus 351 short, sharp, low crest anteriorly just behind the choanae in AMNH 185012, and with a low, narrow, rounded crest in AMNH 212912 (Figs. 11, 12). Sphenoid Complex The sphenoid complex contributes to the roof of the mesocranium, the walls of the orbitotemporal region, and to the floor of the middle cranial fossa. In AMNH 28272, the sphenoid is separated into anterior and posterior parts by a transverse midline gap at a level just anterior to the glenoid fossa (Figs. 18, 19). Each part of the sphenoid complex includes an unpaired element in the mesocranial roof and a pair of wings in the orbitotemporal walls: unpaired presphenoid and paired orbitosphenoid for the anterior part, and unpaired basisphenoid and paired alisphenoid for the posterior part. It is unknown how many ossification centers contribute to the sphenoid complex, and the number varies in different mammals (De Beer 1937; Moore 1981). The serially sectioned juvenile MPIH 6863 preserves only the caudal end of the posterior part, and its basisphenoid and paired alisphenoid are a single ossification as in all the skulls. AMNH 28272 preserves a short midline suture on the endocranial surface of the anteriormost presphenoid, which is suggestive that the anterior part of the sphenoid complex is composed of at least two ossifications. Early developmental stages are needed to fully address whether there is an additional midline ossification, for example, as in Monodelphis (Clark and Smith 1993). The paired pterygoid bone described above underlies the anterior part of the sphenoid complex and is fused to the posterior part. The sphenoid complex is only fully delimited from its neighbors in AMNH 28272 (Figs. 16, 18, 19), with AMNH 185012 preserving all sutures except part of that between the orbitosphenoid and ethmoid (Figs. 11, 14). These two specimens provide the bases for the descriptions of the individual sphenoid elements below. Presphenoid (“ps” in figures) In ventral view in AMNH 28272 (Fig. 18), the presphenoid is roughly trapezoidal, longer than wide, and wider anteriorly than posteriorly, but this entire surface is not exposed on the skull base in the other specimens. The ventral surface of the presphenoid in AMNH 28272 has a paired, low longitudinal ridge off the midline that represents the point of abutment of the (missing) palatines anteriorly and the pterygoids posteriorly. The presphenoid between these two faint ridges is the part exposed in the roof of the basipharyngeal canal. Anteriorly, the presphenoid is underlain by the vomer; posteriorly, it is separated from the basisphenoid (“bs” in Fig. 19) by a gap, the remnant of a synchondrosis. Along the anterior two-thirds of the presphenoid’s lateral edge is a ventrally projecting crest that is entirely hidden by the palatine and pterygoid bones in the other skulls; this crest is termed the presphenoid wing (“psw” in Fig. 19). Wible.indd 351 Fig. 23.—Solenodon paradoxus, AMNH 28271, photograph of left cribriform plate in posterior view. Scale = 3 mm. Abbreviations: ar, annular ridge; cef, cribroethmoidal foramen; cr, central ridge; ec 1, foramina to ectoturbinal 1; ec 2, foramina to ectoturbinal 2; et I, foramina to ethmoturbinal I; et II, foramina to ethmoturbinal II; et III, foramina to ethmoturbinal III; et IV, foramina to ethmoturbinal IV; hs, horizontal sulcus; js, jugum sphenoidale; nt, foramina to nasoturbinate; of, optic foramen; sof, sphenorbital fissure. This crest reaches its maximum height anteriorly where it has a plane suture with the transverse lamina as well as its maximum separation from its fellow of the opposite side. The lateral surface of this crest is exposed in the orbit as the part of the orbitosphenoid ventral to the level of the optic foramen (“of” in Fig. 19). The presphenoid in AMNH 185012 is delimited from the vomer, palatines, and pterygoids, and there is a faint trace of the presphenoidbasisphenoid (intersphenoidal) synchondrosis (Fig. 11). In AMNH 28271, 212912, and CM 18069, only part of the suture with the vomer is preserved (Fig. 12). The endocranial surface of the presphenoid is visible through the foramen magnum in AMNH 28272. Its surface is gently rounded posteriorly, but anterior to the level of the optic foramina the jugum sphenoidale (yoke) is flattened and angled anterodorsally (“js” in Figs. 21C, 23). A midline suture extends posteriorly from the ethmoid suture halfway to the level of the optic foramina. The low posterolateral wall of the presphenoid’s endocranial surface is also visible through the sphenorbital fissure and is in contact with the alisphenoid. In the bisected skull, AMNH 28271, there is a large transverse canal that crosses the midline of the presphenoid ventral to the optic foramina (“tsc” in “ps” in Fig. 21C). 1/6/09 9:25:20 AM 352 Annals of Carnegie Museum Vol. 77 Orbitosphenoid (“os” in figures) The orbital surface of the orbitosphenoid in AMNH 28272 can be divided into two parts: ventral and dorsal. The ventral part is the main orbital exposure; the dorsal part is largely covered by the alisphenoid (Figs. 16, 19). The ventral part is roughly rectangular, longer than high (Figs. 16, 19). On its anterior border, it overlaps the ethmoid ventrally and the frontal dorsally. On its ventral border, it has plane sutures with the (missing) palatine anteriorly and the pterygoid posteriorly. Its posterior border is hidden in lateral view by the alisphenoid; it forms the medial wall of the sphenorbital fissure (“sof” in Figs. 16, 19), which is closed laterally by the alisphenoid, and tapers ventrally into the presphenoid wing. On its dorsal border, it has a plane suture with the frontal anteriorly and is overlapped by the alisphenoid posteriorly; between these two bones is the narrow dorsal part of the orbitosphenoid (see below). AMNH 185012 preserves the sutures on the ventral border with the palatine and pterygoid, and parts of the sutures on the anterior and posterodorsal borders with the fused ethmoid + frontal and alisphenoid, respectively (Fig. 14). Centrally located in the ventral part is the anteriorly directed optic foramen, roughly half a millimeter in diameter (Figs. 16, 19). Extending anteriorly from the optic foramen to the border with the frontal is a groove of similar dimensions. Three specimens show left-right asymmetry in the optic foramen. In AMNH 185012, the right foramen is half the diameter of the left and also placed more ventrally in the orbitosphenoid; in AMNH 212912, the left foramen opens at a level about two millimeters anterodorsal to the right; and in CM 18069, the right foramen opens about a millimeter anterodorsal to the left. Penetrating the orbitosphenoid anteroventral and posteroventral to the optic foramen in AMNH 28272 are small foramina (six on the left and four on the right) that resemble the suboptic foramen identified by Gregory (1910) (“subof” in Fig. 16) as lying just below the optic foramen with its canal running posteroventrally to join the transverse sinus in the presphenoid. This is confirmable in AMNH 28271, where the single suboptic foramen on the right and double on the left join the transverse sinus canal. There is considerable variation within and between specimens in the number of suboptic foramina. The dorsal part of the orbitosphenoid in AMNH 28272 is mainly hidden in direct lateral view, but in oblique ventrolateral view is roughly Y-shaped (Figs. 16, 19). The base is between the frontal anteriorly and alisphenoid posteriorly. The anterior arm contributes to the medial border of the posterodorsal ethmoidal foramen, with the frontal closing the foramen. The posterior arm contributes to the medial border of the anterior opening of the orbitotemporal canal, with the frontal closing the foramen. Much of the endocranial surface of the orbitosphenoid is visible through the foramen magnum in AMNH 28272 (see Fig. 21C). It is a broad wing that climbs roughly Wible.indd 352 halfway up the lateral wall of the anterior part of the middle cranial fossa. The anterior border of the orbitosphenoid is a curved edge that delimits the rostral and middle cranial fossae ventrolaterally. The dorsal border of the orbitosphenoid is pyramidal with the anterior edge having a plane suture with the frontal and the posterior edge overlapped by the parietal. The posterior border is straight and overlapped by the alisphenoid laterally and has a free concave edge medially, which forms the medial wall of the sphenorbital fissure. Near the juncture of the posterior border with the presphenoid is the small optic foramen, and near the posterior extent of the suture with the parietal, the orbitotemporal canal is formed between the orbitosphenoid and parietal. On the left side of the bisected skull AMNH 28271 posterior to the optic foramen is a small foramen that opens into the transverse canal. Basisphenoid (“bs” in figures) In ventral view in AMNH 28272 (Figs. 18, 19), the basisphenoid is roughly trapezoidal. It has a narrow, straight anterior side separated from the presphenoid by a gap, oblique lateral sides that overlie the pterygoid and continue into the orbitotemporal fossa as the alisphenoid, and a wide, straight posterior side that has a plane suture with the basioccipital (“bo” in Figs. 18, 19). The central part of the basisphenoid is essentially flat; the posterolateral corners opposite the anterior pole of the petrosal promontoria are bent slightly dorsally, contributing to the medial border of the piriform fenestrae. AMNH 28272 and 185012 have a small midline foramen positioned just rostral to the center of the bone that likely is the craniopharyngeal canal (“cpc” in Figs. 18, 19, 25, 27A) and the remaining specimens a tiny slit. There is variability among the studied skulls in the part of the basisphenoid in the piriform fenestra, variability both between and among the represented developmental stages. In the juvenile AMNH 28272, the basisphenoid has two tiny prongs of bone that cup but do not surround the internal carotid artery at its endocranial entrance. The lateral of these two prongs is visible in ventral view (“acc” in Fig. 19), but the medial is more dorsally positioned. Because the lateral prong lies lateral to the internal carotid artery it represents an ossification of the alicochlear commissure, the cartilaginous bar of the chondrocranium that connects the processus alaris of the ala temporalis with the front of the auditory capsule (De Beer 1937). As figured by McDowell (1958: fig. 7B), the internal carotid artery in the juvenile solenodon enters the cranial cavity via the piriform fenestra. The right side of the other juvenile, AMNH 185012, resembles the condition in AMNH 28272, but on the left side the lateral of the two prongs has expanded dorsal to the artery and contacts the medial prong to enclose a carotid foramen within the basisphenoid (also on right side of CM 18069); the lateral prong approximates the petrosal and excludes the artery from the piriform fenestra 1/6/09 9:25:20 AM 2008 Wible—On the Cranial Osteology of Solenodon paradoxus (“cf” in Fig. 25). A similar arrangement occurs bilaterally in AMNH 212912 except that a small gap remains between the medial and lateral prongs. In contrast, prongs are lacking entirely in AMNH 28271 and the left side of CM 18069. The dorsal surface of the basisphenoid is accessible in the bisected skull AMNH 28271 (Figs. 20, 21A, B) and through the foramen magnum in AMNH 212912. The basisphenoid is not delimited from either the presphenoid in front or the basioccipital behind, and the bony limits are inferred from the juveniles AMNH 28272 and 185012. Anteriorly, the basisphenoid is gently rounded as was the presphenoid, although the basisphenoid is slightly wider. Posteriorly, there is a shallow hypophyseal fossa, three millimeters in length in AMNH 28271, occupying the space between the paired pars cochlearis of the petrosal bone (“hyf” in Fig. 21C). The anterior and posterior walls of the fossa are only slightly raised in AMNH 28271 (see right side in Fig. 20) and 212912. From its position, the hypophyseal fossa cannot be entirely on the basisphenoid, but must be on the basioccipital as well, and in MPIH 6863, the hypophysis is centered over the spheno-occipital synchondrosis, extending anteriorly over the basisphenoid and posteriorly over the basioccipital. Anteromedial to the hypophyseal fossa in AMNH 28271 is a faint groove for the internal carotid artery running in a broad arc from the piriform fenestra toward the presphenoid (“gica” in Fig. 22). The medial cut edge of the basisphenoid in AMNH 28271 reveals a transverse sinus canal at the level of the foramen ovale (“tsc” in “bs” in Fig. 21C). MPIH 6863 has three sorts of venous foramina that connect to the venous transverse canal: in the ventral surface of the basisphenoid in or near the pterygoid suture (described above), in the lateral aspect of the basisphenoid in a common depression with the alisphenoid canal (described with the alisphenoid below; “tcf” in Figs. 16, 19), and in the dorsolateral aspect of the basisphenoid within the cranial cavity. The last could not be verified in the skulls examined. However, AMNH 28271 has an additional connection to the transverse sinus canal not present in MPIH 6863; a probe pushed into the caudal opening of the pterygoid canal emerges in the transverse sinus canal and then out an aperture into the rear of the cavum epiptericum (Gaupp 1902, 1905), the extradural endocranial space housing the trigeminal ganglion. This aperture, the rostral opening of the pterygoid canal, is within the dorsal surface of the basisphenoid at the level of the transverse canal foramen and is visible through the sphenorbital fissure in all specimens. In MPIH 6863, the pterygoid canal is separated from (passes ventral to) the transverse sinus canal. Alisphenoid (“as” in figures) In ventral view in AMNH 28272 (Figs. 16, 18, 19), the alisphenoid is an irregular shaped quadrangular element. Its medial side is delimited by the entopterygoid and Wible.indd 353 353 caudal processes of the pterygoid (Fig. 19). Its anterior side overlaps the orbitosphenoid ventrally and the frontal dorsally, and slopes anterodorsally such that the anterodorsal corner is rostral to the anteroventral corner. The anterior side (Figs. 16, 19) has a U-shaped cutout ventrally where the alisphenoid forms the lateral wall of the sphenorbital fissure and a L- or J-shaped cutout (left versus right side) dorsally where the alisphenoid rims the depression housing the anterior opening of the orbitotemporal canal, the frontal diploic vein foramen, and the posterodorsal ethmoidal foramen. On its dorsal margin (Figs. 16, 19), the alisphenoid has a straight suture with the parietal and is the concave member of a curved suture with the squamosal. The posterior side is the shortest and forms the anteromedial border of the piriform fenestra, lateral to the caudal opening of the pterygoid canal (Figs. 16, 19). The surface adjacent to the piriform fenestra slopes anteroventrally to the low alisphenoid tympanic process, the preotic crest of McDowell (1958) (“tpas” in Figs. 18, 19, 25). The alisphenoid tympanic process forms the posterior margin of the foramen ovale (“fo” in Figs. 19, 25) and is continuous posterolaterally with the entoglenoid process of the squamosal (“egp” in Figs. 16, 25) and anteromedially with the entopterygoid process, although it does not project as far ventrally as either neighboring process. The bulk of the alisphenoid tympanic process has its main axis oriented coronally, but it bends anteriorly to merge with the back of the parasagittal entopterygoid process. The posterodorsal aspect of the slope posterior to the alisphenoid tympanic process includes an oval depression identified by McDowell (1958) as for the tensor tympani muscle (“ttf” in Fig. 25). Medial to this depression is a faint groove for the auditory tube and lateral to it is a broad groove for the ramus inferior of the stapedial artery (McDowell 1958; MacPhee 1981) and lesser petrosal nerve (“gri” in Figs. 18, 25, 27B), based on MPIH 6863. The composition of this sulcus differs in AMNH 28272 and 185012, the only forms preserving a suture here; in the former the alisphenoid and squamosal contribute equally (Fig. 18), but in the latter it is nearly entirely alisphenoid (Fig. 25). In CM 18069, a dense connective tissue closes the sulcus for the ramus inferior to form a canal; posterior to the alisphenoid, this dense connective tissue canal continues posteriorly below the piriform fenestra and ends at the anterior border of the petrosal. Several foramina penetrate the alisphenoid medial to the glenoid fossa. Anterior to the tympanic process is the round, anteroventrally directed foramen ovale (Fig. 25). Although the foramen ovale is entirely in the alisphenoid, its lateral border has a seam in AMNH 28272 suggesting the foramen was formed by anterior and posterior arms of the alisphenoid meeting lateral to the mandibular nerve (Fig. 19). Anteromedial to the foramen ovale is an oval depression (Fig. 16) that in its anterior half includes the caudal opening of the alisphenoid canal and in its posterior half a smaller opening for the transverse canal foramen (transverse canal of McDowell 1958); the latter opening 1/6/09 9:25:20 AM 354 Annals of Carnegie Museum Vol. 77 Fig. 24.—Solenodon paradoxus, AMNH 185012, line drawing of left braincase in lateral view. Abbreviations: as, alisphenoid; asc, alisphenoid canal; bo, basioccipital; csm, crista supramastoideus; ctpl, lateral section of caudal tympanic process of petrosal; ctpm, medial section of caudal tympanic process of petrosal; e, ectotympanic; egp, entoglenoid process; gf, glenoid fossa; m, malleus (manubrium); me, mastoid exposure of petrosal; pet, petrosal; pp, paroccipital process of petrosal; ptc, posttympanic crest; ptp, posttympanic process; sf, stapedius fossa; sh, stylohyal; smc, suprameatal crest; smef, suprameatal foramen; sq, squamosal; th, tympanohyal; zpsq, zygomatic process of squamosal. is double on the left side and single on the right side of AMNH 28272 (also in CM 18069 and AMNH 212912 with the foramen quite small in both). Rather than an oval depression, there is a round depression in AMNH 28271 and 185012; a transverse canal foramen is absent from the left side of AMNH 185012 (Fig. 14), small and single on the right of AMNH 28271 and 185012, and small and double on the left side of AMNH 28271. These various openings are confirmed as transverse canal foramina based on MPIH 6863. Only the anterior aspect of the endocranial surface of the alisphenoid is visible through the foramen magnum in AMNH 28272 (see Fig. 21C). The alisphenoid has a straight transverse suture with the orbitosphenoid anteriorly and a straight suture angled posterolaterally with the parietal laterally. The anterolateral corner of the alisphenoid is roughly one millimeter medial to the posterior opening of the orbitotemporal canal. What is visible of the alisphenoid is confined to the braincase floor. Sutures between the alisphenoid and its endocranial neighbors are not preserved in the bisected skull AMNH 28271. Wible.indd 354 Squamosal (“sq” in figures) The paired squamosal is a major contributor to the external sidewall of the posterior braincase and the anterolateral basicranium; it also has a narrow exposure in the posterolateral floor of the middle cranial fossa and on the ventrolateral occiput. The squamosal is separated by sutures from its neighbors externally in AMNH 28272 (Figs. 5, 16, 18) and 185012 (Figs. 6, 11), and only along the posterior suture with the petrosal in AMNH 28271, 212912, and CM 18069 (Fig. 12). Most of the sutures between the squamosal and neighbors endocranially are preserved in the bisected skull AMNH 28271 (Fig. 21C). In dorsal view, the most visible part of the squamosal is the triangular zygomatic process (“zpsq” in Figs. 2, 5). The zygomatic process ends in a short, anteriorly directed point, which is broken on the left side of AMNH 185012 (Fig. 2), the right side of AMNH 28272 (Fig. 5), and CM 18069 (Fig. 4); a sharp anterior point seems to be lacking naturally in AMNH 28271. Posterior to the tip, the dorsolateral edge of the zygomatic process, the crista supramastoidea of the Nomina Anatomica Veterinaria (1994), has a raised crest roughly over the anteroposterior length of 1/6/09 9:25:21 AM 2008 Wible—On the Cranial Osteology of Solenodon paradoxus the glenoid fossa (“csm” in Fig. 24). Behind the crest, the dorsolateral edge of the squamosal represents the top of the suprameatal crest and posttympanic process (see below). The relatively flat, horizontal surface medial to the dorsolateral edge is penetrated by a variable number (between three and six) of tiny to small foramina in all specimens. Based on MPIH 6863, these foramina drain veins into the substance of the squamosal and the horizontal surface provides attachment for the temporalis muscle. In lateral view in AMNH 28272 (Fig. 16) and 185012 (Fig. 6), the squamosal’s contribution to the lateral braincase has an irregular arrowhead shape with the point directed anteriorly. The squamosal can be divided into two parts by their relation to the glenoid fossa (“gf” in Figs. 6, 16), the squama rostrally and the caudal process. The tip of the squama, the point of the arrowhead, contacts the alisphenoid (Figs. 14, 16). Behind the tip, the squamosal overlaps the ventral margin of the parietal along a fairly straight suture that first is angled posterodorsally and then turns posteriorly before ending at the nuchal crest (Fig. 6). The posterior border of the squamosal is more completely preserved in AMNH 185012 (Figs. 24, 34); it forms the anteroventral part of the nuchal crest along with the mastoid exposure of the petrosal. The nuchal crest is not vertical but is angled anteroventrally (Figs. 6, 7). Near its midpoint the posterior border of the squamosal has a small concavity that accommodates an oval exposure of the mastoid on the lateral braincase wall (Fig. 24). The ventral border of the squamosal is free, inflected medially on the basicranium. The posterior two-thirds represent the crista supramastoidea over the glenoid fossa, the suprameatal crest over the external acoustic meatus (“smc” in Fig. 24), and posttympanic process (“ptp” in Fig. 24). A well-developed, laterally directed foramen for ramus temporalis penetrates the caudal process near the parietal suture dorsal to the suprameatal crest in AMNH 28272 and 185012 (“rt” in Figs. 2, 4, 6). A foramen in a comparable position occurs in the other specimens, but the parietosquamosal suture is obliterated (Fig. 7). Additional smaller, posterodorsally directed foramina for rami temporales occur nearer or within the parietosquamosal suture in AMNH 28272 (Fig. 5) and 185012 (Figs. 2, 6). The left side of AMNH 28272 (Fig. 5) has two in the squamosal and one in the parietosquamosal suture; and the right side has two in the suture. The right side of AMNH 185012 (Fig. 2) has one within the squamosal and three in the parietosquamosal suture; the left side has one in the suture. Similar foramina occur in the other specimens (Figs. 4, 7), but their bony relationship cannot be ascertained, because as noted above the parietosquamosal suture is gone. In ventral view in AMNH 28272 (Fig. 18) and 185012 (Figs. 11, 25), the squamosal can be divided front to back into preglenoid, glenoid, and postglenoid areas. The pre- and postglenoid areas, the ventral aspects of the squama and caudal process respectively, are positioned dorsal to the glenoid. Based on AMNH 28272 (Fig. 18), the triangular preglenoid and oval glenoid areas have a medial Wible.indd 355 355 foliate suture at which the squamosal underlies the alisphenoid, and the quadrangular postglenoid area has a plane suture along its posteromedial and posterior borders with the petrosal. The oval glenoid area, which includes the glenoid fossa, zygomatic process, and entoglenoid process (“egp” in Fig. 25), has its long axis directed from posteromedial to anterolateral. McDowell (1958:142) described the glenoid fossa in detail: “On specimens of Solenodon paradoxus with the glenoid articular apparatus dried in place, two separate ovoid spots of cartilage can be seen on the glenoid surface of the squamosal. One is on the external portion of the glenoid fossa (the portion of the fossa borne by the vestige of the zygomatic portion of the squamosal); this, the external capitular facet, faces directly ventrad. The other capitular facet lies more mesially, on the projecting postglenoid process [entoglenoid of this report]; this the postglenoid [entoglenoid] capitular facet, faces forward and dorsad. The external and postglenoid [entoglenoid] capitular facets are quite separate on the squamosal.” These two facets articulate with corresponding facets on the mandible (see below). The pronounced entoglenoid process, which buttresses the medial and posteromedial glenoid fossa, is tongue shaped and angled obliquely from posterolateral to anteromedial (Fig. 25). It is continuous medially with the low tympanic process of the alisphenoid (Fig. 25), best seen in the adults (Fig. 12). A variety of terms have been employed for this process on the squamosal: postglenoid process (Allen 1910), postglenoid (entoglenoid) process (Gregory 1910), modified entoglenoid process (McDowell 1958; MacPhee 1981), pseudopostglenoid (entoglenoid) process (Novacek 1986a), and pseudoglenoid process (MacPhee 1994). McDowell (1958:172) concluded that the solenodon process is not equivalent to the postglenoid process of most mammals, but confusingly throughout the descriptions and illustrations of Solenodon he employed the term postglenoid process, which he meant in a generic way for “any kind of projection of the squamosal forming a posterior brace for the squamosal-dentary articulation.” Following McDowell (1958), the term entoglenoid process is used here, because this process is medial to the main glenoid surface. Additionally, near the midpoint of the posterior surface of the entoglenoid process is a narrow groove for the chorda tympani nerve (McDowell 1958; “gct” in Fig. 25); the chorda tympani nerve lies medial or dorsomedial to a true postglenoid process (McDowell 1958; MacPhee 1981). Posteroventral to the glenoid fossa and entoglenoid process is the narrow, quadrangular postglenoid area (Fig. 25). The most conspicuous feature of the postglenoid area is the large postglenoid foramen (“pgf” in Figs. 25, 27A), which is situated posterior to the lateral margin of the entoglenoid process. Extending ventrally from the postglenoid foramen onto the posterior face of the entoglenoid process is a broad groove for the postglenoid vein. In the intact skull, the surface anteromedial to the postglenoid foramen is covered by the anterior crus of the ectotympanic (“e” in Fig. 25) and the anterior process of the malleus. 1/6/09 9:25:21 AM 356 Annals of Carnegie Museum Vol. 77 In fact, the anterior crus appears to form the medial wall of the postglenoid foramen, but actually contributes to the medial wall of the groove for the postglenoid vein immediately ventral to the postglenoid foramen (cf. right and left sides in Fig. 25). The ectotympanic is missing from one side in four specimens (Figs. 12, 18; right side of AMNH 28271, 28272, 185012; left side of CM 18069). In two of these (AMNH 185012; CM 18069), there is a narrow facet on the squamosal anteromedial to the postglenoid foramen for the ectotympanic and rostral process of the malleus (“efc” in Fig. 25). Bilaterally in the juvenile AMNH 28272 is a foramen medial to the postglenoid foramen that opens endocranially (Figs. 26, 27); in MPIH 6863, this foramen is an additional route for venous blood to the postglenoid vein. Much smaller versions of this opening occur bilaterally in AMNH 185012 and on the right side of AMNH 28271, but in the latter the foramen is within the medial aspect of the groove for the postglenoid vein. Posteromedial to and of similar girth to the postglenoid foramen is a depression, the epitympanic recess, the space over the incudomallear joint (Klaauw 1931; “er” in Figs. 25, 26B, 28). The anterolateral half of the epitympanic recess is on the squamosal and the posteromedial half on the petrosal. The remaining postglenoid area posterolateral to the postglenoid foramen and epitympanic recess includes a central depression and two eminences at the posterior and posteromedial aspects connected by a ridge. The central depression, which housed the external acoustic meatus, has an irregular surface medially and smooth surface laterally (“eam” in Figs. 25, 26B). The eminence along the posterior border is the posttympanic process of the squamosal (“ptp” in Figs. 24, 25, 26B, 29B), the back of which has a large depression that based on MPIH 6863 is for the common tendon of the sternomastoid and cleidomastoid muscles of Allen (1910). The eminence along the posteromedial border is the posttympanic crest (“ptc” in Figs. 24, 25, 26B, 29B), which Wible et al. (2004) named for a more pronounced process in the Late Cretaceous eutherian Zalambdalestes. The solenodon posttympanic crest contacts the tympanohyal (“th” in Figs. 25, 29B) and the posterior crus of the ectotympanic (Fig. 25); Wible et al. (2004:82) reported the former contact in Zalambdalestes and speculated the latter as well. In AMNH 212912, the posttympanic crest also has a narrow contact with the stylohyal (see “sh” in Fig. 25). All solenodon specimens have one or more small foramina either in the anterior base of the posttympanic crest or in the central depression for the external acoustic meatus. Gregory (1910; “f.sb.sq.” in Fig. 1) identified the one on the left side of AMNH 28272 as a subsquamosal foramen transmitting a vein; the right side of AMNH 28272 has seven foramina across this part of the squamosal (three of which are labeled “smef” in Fig. 27A). MPIH 6863 has a similar tiny opening that transmits a branch off the ramus posterior of the stapedial artery. Because these openings lie inferior to the suprameatal crest, they are identified as suprameatal foramina. Wible.indd 356 The endocranial surface of the squamosal is fully exposed in the bisected skull AMNH 28271 (Fig. 21C) and partially visible through the piriform fenestra in AMNH 28272. The latter preserves sutures delimiting the squamosal entirely from its neighbors, and the former preserves the petrosquamous suture and parts of the sutures with the parietal (Fig. 21C). Only a narrow endocranial exposure of the squamosal anterior to the petrosal is present; this represents the inner surface of the caudal process of the squamosal and an endocranial exposure of the squama is lacking. The squamosal contacts the parietal anteriorly and the alisphenoid ventrally. The bulk of the squamosal exposure is a broad sulcus transmitting the prootic sinus (“sps” in Fig. 21C) to its exit on the skull base at the postglenoid foramen. In the ventral half of this groove are two foramina (“1” and “2” in Fig. 21C), one posterodorsal and the other anteroventral, leading to the single external postglenoid foramen. On the right side of AMNH 28271, the two internal apertures are next to each other, but on the left side they are separated. Both apertures can be seen from the postglenoid foramen on the exterior bilaterally in AMNH 28271, 28272, and on the left side of AMNH 212912. In the dorsal part of the sulcus for the prootic sinus is the internal orifice for a foramen for ramus temporalis (“rt” in Fig. 21C). Petrosal (“pet” in figures) The paired petrosal is usually divided into the anteroventromedial pars cochlearis, enclosing the cochlear duct and saccule, and the posterodorsolateral pars canalicularis, enclosing the utricle and semicircular canals. The therian petrosal presents four surfaces: tympanic or ventral, cerebellar or dorsal, squamosal or lateral, and lambdoid or mastoid (MacIntyre 1972; Wible 1990). Much of the squamosal surface is visible in the juvenile AMNH 28272, because the petrosal and squamosal bones are narrowly separated. The remaining three surfaces can be viewed in all specimens. The dorsal surface is best viewed in the bisected skull of AMNH 28271, but part of the endocranial surface is visible through the foramen magnum in the remaining specimens. Ventral View (Figs. 25–28).—In ventral view, the pars cochlearis is represented by the ovoid cochlear housing, whose long axis is oblique, from posterolateral to anteromedial. The pars cochlearis abuts the basioccipital and basisphenoid medially and anteromedially, and is continuous with the pars canalicularis posteriorly and laterally; most of the anterior border of the pars cochlearis contributes to the posterior edge of the piriform fenestra. Centrally located on the ovoid pars cochlearis and recessed from its medial and anterior borders is a raised, round hill, the promontorium of the petrosal (“pr” in Figs. 25, 26B), reflecting the coiling of the cochlear duct through three or slightly more turns in MPIH 6863. The juvenile AMNH 28272 has a flatter, less protuberant promontorium than the other specimens (Figs. 19, 26, 27). 1/6/09 9:25:21 AM 2008 Wible—On the Cranial Osteology of Solenodon paradoxus 357 Fig. 25.—Solenodon paradoxus, AMNH 185012, line drawing of basicranium in ventral view. Tympanohyal is fused to lateral section of the caudal tympanic process of petrosal (not labeled; see Figs. 26B, 28, 29). Abbreviations: as, alisphenoid; asc, alisphenoid canal; bo, basioccipital; bs, basisphenoid; cf, carotid foramen; cpc, craniopharyngeal canal; ctpm, medial section of caudal tympanic process of petrosal; e, ectotympanic; eam, roof of external acoustic meatus; efc, ectotympanic facet on squamosal; egp, entoglenoid process; eo, exoccipital; er, epitympanic recess; fm, foramen magnum; fo, foramen ovale; fs, facial nerve sulcus; gct, groove for chorda tympani nerve; gf, glenoid fossa; gri, groove for ramus inferior of stapedial artery; hf, hypoglossal foramina; ips, inferior petrosal sinus groove; jf, jugular foramen; m, malleus (manubrium); mc, mastoid canaliculus; me, mastoid exposure of petrosal; oc, occipital condyle; on, odontoid notch; pc, pterygoid canal; pcop, paracondylar process; pf, piriform fenestra; pgf, postglenoid foramen; pp, paroccipital process of petrosal; pr, promontorium of petrosal; pt, pterygoid; ptc, posttympanic crest; ptp, posttympanic process; rtp, rostral tympanic process of petrosal; sf, stapedius fossa; sh, stylohyal; smn, stylomastoid notch; sq, squamosal; th, tympanohyal; tpas, tympanic process of alisphenoid; ttf, tensor tympani muscle fossa; vcof, ventral condyloid fossa. In the posterolateral surface of the promontorium is an elliptical opening, the oval window or fenestra vestibuli, which accommodates the footplate of the stapes (“fv” in Figs. 26B, 28). The length and width of five oval windows were measured to calculate the stapedial ratio of Segall (1970) with the average being 3.02; the remainder was obscured from view. The values are 2.9 and 3.0 on the left and right side of AMNH 28272; 3.1 and 3.0 on the left and right side of AMNH 185012; and 3.1 on the right side of AMNH 28271. The fenestra vestibuli is nearly vertical, with the dorsal rim only slightly lateral to the ventral rim. The posterior half of the fenestra vestibuli is recessed slightly from the neighboring promontorial surface, producing a narrow vestibular fossula, best developed posterodorsally. Centrally positioned in the posterior surface of the promontorium is a kidney-bean shaped opening that is hidden from view by tympanic processes described below, except on the right side of AMNH 28271 and left side of CM 18069 where the processes are broken off (“cfo” in Fig. 28). McDowell (1958) identified this opening in Solenodon as the fenestra rotunda or fenestra cochleae, but MacPhee (1981) correctly identified it as the aperture of the cochlear fossula. The fenestra cochleae, the aperture closed by the secondary tympanic membrane, is recessed Wible.indd 357 from the exterior of the promontorium; this is well shown on the right side of AMNH 28271 because the secondary tympanic membrane is preserved in situ. Between the fenestra cochleae and the aperture of the cochlear fossula lies the cochlear fossula, a “funnel-shaped niche in auditory capsule which contains fenestra cochleae and hides it from view” (MacPhee 1981:51). Medial to the promontorium is a rostral tympanic process of the petrosal that extends the length of the pars cochlearis and varies in height (“rtp” in Figs. 25, 26B, 29A). In its anterior two-thirds, the rostral tympanic process is a low ridge (not projecting as far ventrally as the promontorium) that decreases slightly in height anteriorly (Figs. 26A, B, 29A); the ventral margin of this ridge is sharp in AMNH 28271 and 28272 but blunter in the other skulls. In contrast, in its posterior one-third, the rostral tympanic process is expanded into a high, laminar, quadrangular element that contacts the posterior crus of the ectotympanic ring and is continuous with another high, laminar, quadrangular element originating from the pars canalicularis, a caudal tympanic process of the petrosal (“ctpm” in Fig. 25). The line of origin for the solenodon rostral tympanic process is strikingly similar to that of MacPhee’s (1981: fig. 2) rostral tympanic process in his schematic placental ear region including its posterior origin at the 1/6/09 9:25:22 AM 358 Annals of Carnegie Museum Vol. 77 posteromedial margin of the aperture of the cochlear fossula. In his study of the juvenile solenodon serial sections (MPIH 6863), MacPhee (1981) reported the rostral tympanic process as absent, and upon restudy of this specimen the oversight is understandable. The rostral tympanic process is present, but much less pronounced in height and length in MPIH 6863 than in the studied skulls. Near the posterior limit of the rostral tympanic process medial to the aperture of the cochlear fossula is a small opening through the process (“tca” in Figs. 27A, 29A). Based on MPIH 6863, this opening transmits the tympanic nerve, a branch of the glossopharyngeal nerve, and, therefore, is a tympanic canaliculus. Dorsomedial to the rostral tympanic process is a shallow vascular sulcus running along the medial face of the pars cochlearis between the anterior pole and the jugular foramen (“ips” in Figs. 25, 29A). This sulcus can be seen in all specimens except the juvenile AMNH 28272 where glue and tight approximation of the petrosal and basioccipital hinder observation. Based on MPIH 6863, the occupant of this sulcus is the inferior petrosal sinus. Dorsal to the sulcus for the inferior petrosal sinus, the pars cochlearis overlaps the basioccipital at a squamous suture based on the right side of AMNH 28271, forming a roof over the sulcus for the inferior petrosal sinus. There is also a partial floor to the groove formed by a lamina on the pars cochlearis, again visible in all specimens except AMNH 28272, although it is barely perceptible in AMNH 28271. The extent of this lamina varies; it runs the length between the anterior pole and jugular foramen in AMNH 185012 but is confined to the rostral half of the pars cochlearis in CM 18069 and AMNH 28271 and 212912. In MPIH 6863, the inferior petrosal sinus exits the skull via the piriform fenestra, receiving the pterygoid vein running posteriorly ventral to the basisphenoid, then runs posteriorly ventral to the lateral edge of the basioccipital and medial edge of the pars cochlearis, and joins the internal jugular vein beneath the jugular foramen. Anterior to the promontorium the pars cochlearis is prolonged into a shelf, which following MacPhee’s (1981) terminology is an epitympanic wing of the petrosal (“ew” in Figs. 19, 26B). The solenodon epitympanic wing is not flat, but undulates with the central part a rounded column directed anteromedially and positioned ventral to concavities on either side of it. The lateral concavity is a fossa for the tensor tympani muscle based on MPIH 6863, and the smaller, shallower medial concavity is bordered medially by the rostral tympanic process. The central column on its lateral surface bears a groove for the internal carotid artery (see below) directed anteromedially toward the basisphenoid. The maximum length of the epitympanic wing varies between one-third in the juvenile AMNH 28272 and onehalf in the adult AMNH 28271 of the maximum length of the promontorium. The ventral surface of the solenodon promontorium bears grooves for the internal carotid circulation, which have been described elsewhere (McDowell 1958; MacPhee 1981). Wible.indd 358 At the posterior end of the low anterior part of the rostral tympanic process is a shallow millimeter wide concavity that indicates the entrance of the internal carotid artery into the middle ear (“gica” in Figs. 27A, 28). A similar size groove runs laterally from the entrance point towards the fenestra vestibuli. About a millimeter medial to the fenestra vestibuli, this groove divides into an anteromedially directed groove for the continuation of the internal carotid artery and a laterally directed groove for the stapedial artery (“gsa” in Figs. 26B, 28). The former runs the length of the promontorium and epitympanic wing; the latter ends at the fenestra vestibuli, specifically at the posterior half of the ventromedial border of the fenestra vestibuli. Stapes are preserved within the fenestra vestibuli bilaterally in AMNH 212912 and CM 18609; on the right side of the latter dried blood representing the stapedial artery passes through the large stapedial (intercrural) foramen. MacPhee (1981) noted that the stapedial artery at its origin was about twice the diameter of the rostral continuation of the internal carotid artery in MPIH 6863. The grooves are hard to measure at their division in most of the studied skulls, because they are obscured by the petrosal tympanic processes and ectotympanic. However, the right side of AMNH 28271 (Fig. 28) and left of CM 18069 are missing the tympanic processes and ectotympanic; here the groove for the stapedial artery is 0.9 mm and that for the rostral continuation of the internal carotid artery is 0.5 mm. The pars canalicularis is essentially a horizontal shelf with various processes, sulci, and spaces on its ventral surface lying posterior and lateral to the pars cochlearis. The pars canalicularis has squamous sutures posteromedially with the exoccipital and laterally with the squamosal. The juvenile AMNH 28272 serves as the basis for description, because its auditory ossicles and ectotympanic are removed, fully exposing the pars canalicularis. However, some ossification features are not as developed as in the older skulls. Dominating the lateral part of the pars canalicularis is a longitudinal crest, which represents the crista parotica (“cp” and “pcp” in Fig. 26B) and its derivatives. Near the middle of this longitudinal crest is the attachment of the tympanohyal (“th” in Fig. 26B), which for the purposes of description is used to divide the crest into anterior and posterior halves. By definition, the point of attachment of the tympanohyal on the auditory capsule is the crista parotica (De Beer 1937; MacPhee 1981). The tympanohyal is a 1.3 mm long, rod-shaped, near vertical projection in AMNH 28272, directed slightly anteriorly and medially. Its ventral end has an oval facet for the missing stylohyal, which is preserved in situ on the left side of AMNH 185012 (“sh” in Figs. 25, 29) and 212912. The stylohyal facet is directed posteroventrally. The lateral surface of the tympanohyal base contacts the posttympanic crest of the squamosal in all specimens except AMNH 28272, but this absence appears artificial, produced by shifting of the bones after death. In the skulls preserving the ectotympanic, the posterior crus contacts the tip of the tympanohyal medial to the stylohyal facet (Figs. 25, 29B). 1/6/09 9:25:22 AM 2008 Wible—On the Cranial Osteology of Solenodon paradoxus 359 Fig. 26.—Solenodon paradoxus, AMNH 28272, drawings of right ear region in ventral view. A, shaded drawing; B, line drawing; C, line drawing with internal carotid artery and main branches in place based on MacPhee (1981) and MPIH 6863. Arrow in B points to hidden base of lateral section of the caudal tympanic process on the crista interfenestralis, the bar of bone between the fenestra vestibuli and the aperture of the cochlear fossula. Scale is for B and C. Abbreviations: as, alisphenoid; bo, basioccipital; bs, basisphenoid; cp, crista parotica; ctpl, lateral section of caudal tympanic process of petrosal; ctpm, medial section of caudal tympanic process of petrosal; eam, roof of external acoustic meatus; eo, exoccipital; er, epitympanic recess; ew, epitympanic wing of petrosal; fs, facial nerve sulcus; fv, fenestra vestibuli; gct, groove for chorda tympani nerve; gsa, groove for stapedial artery (posterior part); hf, hypoglossal foramina; ica, internal carotid artery; jf, jugular foramen; mb, muscular branch; mfc, mallear facet on crista parotica; mnb, meningeal branch; oc, occipital condyle; pa, posterior auricular artery; pcp, posterior continuation of crista parotica; pf, piriform fenestra; pp, paroccipital process of petrosal; pr, promontorium of petrosal; ptc, posttympanic crest; ptp, posttympanic process; ri, ramus inferior of stapedial artery; rio, ramus infraorbitalis; rm, ramus mandibularis; rp, ramus posterior of stapedial artery; rs, ramus superior of stapedial artery; sa, stapedial artery; sf, stapedius fossa; sma, suprameatal artery; th, tympanohyal; tpas, tympanic process of alisphenoid; tt, tegmen tympani; vcf, ventral condyloid foramen. Wible.indd 359 1/6/09 9:25:23 AM 360 Annals of Carnegie Museum Vol. 77 Fig. 27.—Solenodon paradoxus, AMNH 28272, drawings of right ear region in oblique ventral view. A, line drawing; B, line drawing with lateral head vein, facial nerve, and auricular branch of the vagus nerve in place based on MPIH 6863. Abbreviations: abX, auricular branch of vagus nerve; cpc, craniopharyngeal canal; efc, ectotympanic facet on squamosal; fn, facial nerve; fo, foramen ovale; gf, glenoid fossa; gg, geniculate ganglion; gica, groove for internal carotid artery; gpn, greater petrosal nerve; gri, groove for ramus inferior of stapedial artery; gsa, groove for stapedial artery (anterior part); hF, hiatus Fallopii; lhv, lateral head vein; lhvs, sulcus for lateral head vein; lwfi, lateral wall of fossa incudis; mc, mastoid canaliculus; pc, pterygoid canal; pcop, paracondylar process; pgf, postglenoid foramen; prc, prootic canal; smef, suprameatal foramina; smn, stylomastoid notch; tca, tympanic canaliculus. The posterior half of the longitudinal crest (“pcp” in Fig. 26B) is the posterior continuation of the crista parotica or lateral section of the caudal tympanic process situated lateral to the stapedius fossa (MacPhee 1981); the former term is employed here. The posterior continuation of the crista parotica is near vertical and uniform in height. It is thinnest immediately posterior to the tympanohyal, with a faint concavity on the medial surface marking the stylomastoid notch (“smn” in Fig. 27A), the exit of the facial nerve from the ear region (Fig. 27B). It is thickened posteriorly where it abuts the posttympanic process of the squamosal at the base of the nuchal crest; this represents the paroccipital process of the petrosal (see Wible and Gaudin 2004; “pp” in Figs. 26B, 29B). The surface dorsolateral to the posterior continuation of the crista parotica is angled ventromedially and abuts the squamosal, with the pars canalicularis slightly concave, as visible in AMNH 28272 where an artificial narrow gap separates the two bones. The anterior half of the longitudinal crest has a medial section extending to the piriform fenestra and a shorter but higher lateral section. The lateral section (“lwfi” in Fig. 27A) arises from the anterolateral base of the tympanohyal and extends forward anterolaterally for a millimeter. Its lateral surface is in contact with the posttympanic crest of the Wible.indd 360 squamosal. The lateral section is a thin, sharp, vertical crest that is low posteriorly and ends in an anteroventrally projecting prong based on the right sides of AMNH 185012 and 212912; this process is blunt on the left side of AMNH 28272 and broken on the right. The bulk of this crest forms the lateral wall of the fossa incudis (not visible in ventral view), housing the crus breve of the incus, with the anterior prong contributing to the posterolateral wall of the epitympanic recess (described above in Squamosal). The fossa incudis is a small, shallow, anteromedially directed, near vertical depression set about a half millimeter posterior to (and continuous with) the epitympanic recess immediately anterior to the tympanohyal attachment. The medial section of the longitudinal crest’s anterior half is the crista parotica (“cp” in Fig. 26B). It follows a sinuous course between the anteromedial base of the tympanohyal and the piriform fenestra. It has a near vertical base attached to the overlying horizontal shelf of the pars canalicularis and a sharp ventral end that is bent medially to form the lateral edge of an incomplete horizontal floor of the lateral head vein sulcus and facial sulcus (see below). Posteriorly, it forms the low-lying medial wall of the fossa incudis and anteriorly, the medial wall of the epitympanic recess. In AMNH 28272, the crista parotica ends in 1/6/09 9:25:24 AM 2008 Wible—On the Cranial Osteology of Solenodon paradoxus an anteroventromedially directed prong, posterior to which is a millimeter long facet (“mfc” in Fig. 26B) and a second prong (double on the right side). Based on the left side of AMNH 185012 and both sides of AMNH 212912, this facet contacts a thick process on the rostral (anterior) process of the malleus. Also, based on MPIH 6863, the tendon of the tensor tympani muscle runs behind the prong posterior to the mallear facet. Medial to the crista parotica is a longitudinal space running the length of the lateral part of the pars canalicularis. This space is widest in its posterior half between the posterior continuation of the crista parotica and caudal tympanic process (see below) where it accommodates the fossa for the stapedius muscle (“sf” in Figs. 26B, 28). The ovoid stapedius fossa has a long axis of some one and a half millimeters set obliquely anterolateral to posteromedial. The raised posterior rim of the stapedius fossa is formed by the lateral semicircular canal. The narrower anterior half of the space medial to the crista parotica is bordered medially by the pars cochlearis and provides passage for three principal structures, the facial nerve (“fn” in Fig. 27B), the lateral head vein (“lhv” in Fig. 27B), and the stapedial artery (“sa” in Fig. 26C). This space is described by tracing the course of these three structures, based on MPIH 6863. The facial nerve leaves the cranial cavity on the endocranial surface of the petrosal via the facial canal in the foramen acusticum superius of the internal acoustic meatus (described below; “fac” in Fig. 21C). After a short course through the facial canal, the nerve enters a space within the pars cochlearis hidden from external view, the cavum supracochleare, where the nerve expands into the geniculate ganglion (“gg” in Fig. 27B). There are two conduits from the cavum supracochleare, neither of which is fully visible in ventral view in AMNH 28272, the hiatus Fallopii for the greater petrosal nerve (“gpn” in Fig. 27B) and the secondary facial foramen for the continuation of the facial nerve (“fn” in Fig. 27B). The smaller hiatus Fallopii (“hF” in Figs. 27A, 28) lies near the middle of the anterior border of the tensor tympani fossa in the posterior border of the piriform fenestra and opens anteromedially; the secondary facial foramen lies anterior to the fenestra vestibuli and opens posterolaterally. The hiatus Fallopii is partially hidden by an anteroventromedially directed spine (“tt” in Figs. 26B, 28), which continues posteriorly to the fenestra vestibuli as a low crest that fully conceals the secondary facial foramen. The spine, crest, and bone between the hiatus Fallopii and secondary facial foramen represents the tegmen tympani (see below) and forms the floor of the cavum supracochleare and the roof of the lateral part of the tensor tympani fossa. Several authors (e.g., Rougier et al. 1998; SánchezVillagra and Wible 2002) have considered the position of the hiatus Fallopii as a character in phylogenetic analyses. Three states are usually identified with the principal difference being the relative proportions of the ventral floor and dorsal roof of the hiatus to one another: a dorsal Wible.indd 361 361 Fig. 28.—Solenodon paradoxus, AMNH 28271, photograph of right ear region in ventral view. Dashed lines circumscribe the broken bases of the posterior part of the rostral tympanic process of the petrosal and the medial and lateral sections of the caudal tympanic process of the petrosal. The opening in the midst of these broken bases is the aperture of the cochlear fossula; the cochlear fossula is the depression just inside the aperture. Anterior to and in a plane perpendicular to the cochlear fossula is the preserved secondary tympanic membrane (not visible here), which defines the fenestra cochleae. Scale = 2 mm. Abbreviations: as, alisphenoid; bo, basioccipital; bs, basisphenoid; cfo, cochlear fossula; ctpl(br), broken lateral section of caudal tympanic process of petrosal; ctpm(br), broken medial section of caudal tympanic process of petrosal; er, epitympanic recess; fs, facial sulcus; fv, fenestra vestibuli; gica, groove for internal carotid artery; gsa, groove for stapedial artery (posterior part); jf, jugular foramen; pf, piriform fenestra; pps, postpromontorial tympanic sinus; psc, posterior semicircular canal; ptc, posttympanic crest; sq, squamosal; tt, tegmen tympani. hiatus position has the floor projecting anterior to the roof; an intermediate position has the floor and roof subequal in their anterior projection; and a ventral position has the roof projecting anterior to the floor. The solenodon specimens exhibit all three states: a dorsal position occurs in AMNH 212912, an intermediate in AMNH 185102, and a ventral in AMNH 28271 (Fig. 28). Technically, the juvenile AMNH 28272 has a ventral position, but it is not far removed from an intermediate one (Fig. 27). It is cautioned that in instances where the hiatus Fallopii is at the anterior border of the petrosal, such as the solenodon and Monodelphis (see Wible 2003), characters concerning the position of the aperture may not be very informative. Posterior to the secondary facial foramen, between the crista parotica and the pars cochlearis on the right side of AMNH 28272 is a roughly V-shaped space, with the base pointing posteriorly toward the stapedius fossa. The longer 1/6/09 9:25:25 AM 362 Annals of Carnegie Museum Vol. 77 medial leg of the V is the facial sulcus (“fs” in Figs. 26B, 28), which transmits the facial nerve from the secondary facial foramen to the stylomastoid notch posterior to the tympanohyal. The shorter lateral leg of the V is a sulcus (“lhvs” in Fig. 27A) for a vessel in MPIH 6863 that is identified here as the lateral head vein (“lhv” in Fig. 27B), because of its resemblance to the vein of the same name known for monotremes and some marsupials among extant mammals (Wible 1990; Wible and Hopson 1995; Rougier and Wible 2006). The lateral head vein sulcus ends at two small, anterolaterally directed foramina opposite the fenestra vestibuli (the anterior one at the level of the back of the epitympanic recess; “prc” in Fig. 27A); it is possible to see anterolaterally through these two foramina to the squamosal surface of the pars canalicularis (described below). The lateral head vein sulcus is much shorter on the left side of AMNH 28272, because the two small foramina are more posteriorly place (the anterior one at the level of the fossa incudis). Between the legs of the V (i.e., between the facial sulcus and lateral head vein sulcus) is a rounded eminence that appears to represent the ampulla of the lateral semicircular canal. A lateral head vein sulcus is lacking in the remaining examined specimens, but a foramen comparable in size to the hiatus Fallopii resembling the double ones in AMNH 28272 is visible bilaterally in AMNH 28271 and on the right side of AMNH 212912 at the level of the tympanohyal. Such foramina appear to be lacking on the left side of AMNH 212912 and bilaterally in AMNH 185012, but might be hidden from view by the anterior continuation of the crista parotica. On the left side of AMNH 28271, the bisected skull, a hair was passed through the foramen and was traced to a small opening in the squamosal within the sulcus for the prootic sinus just dorsal to the postglenoid foramen. The same course is present in MPIH 6863, that is, a connection between the lateral head vein and prootic sinus through a canal in the pars canalicularis and a small foramen in the squamosal. In its position, contents, and connections, the venous conduit through the pars canalicularis represents a prootic canal and the opening on the ventral surface of the pars canalicularis is a tympanic aperture of the prootic canal. Since it original description in the echidna by Gaupp (1908), a prootic canal has been found among extant mammals in the platypus and some marsupials and is commonly present among Mesozoic mammaliaforms (Wible 1990; Wible and Hopson 1995; Rougier and Wible 2006), including the Late Cretaceous eutherian Maelestes Wible et al., 2007 (see Wible et al. 2007, in press) and isolated petrosals referred to the Early Cretaceous eutherian Prokennalestes Kielan-Jaworowska and Dashzeveg, 1989 (see Wible et al. 2001) and Late Cretaceous zhelestids (Ekdale et al. 2004). The discovery of a prootic canal in the solenodon is the first for any placental, extant or extinct. The third neurovascular structure to consider is the stapedial artery (see also McDowell 1958). After penetrating the stapedial foramen in the stapes, the stapedial artery (“sa” in Fig. 26C) turns anteriorly ventral to the facial Wible.indd 362 nerve in the facial sulcus. At the secondary facial foramen, where the facial nerve bends anteromedially to enter the cavum supracochleare, the stapedial artery continues forward in a millimeter long sulcus before reaching the piriform fenestra (“gsa” in Fig. 27A). The higher lateral wall of this sulcus is formed by the anterior continuation of the crista parotica and the medial wall is formed by the tegmen tympani. A last issue to consider with the lateral part of the pars canalicularis is the tegmen tympani, which generally is considered a neomorphic component of the chondrocranium in mammals (DeBeer 1937; Moore 1981), although it is reported by some (e.g., Kuhn and Zeller 1987) to be lacking in monotremes. The tegmen tympani is produced forward from the crista parotica and forms a new side wall of the cranial cavity lateral to the primary side wall represented by the prefacial (suprafacial) commissure (DeBeer 1937; Moore 1981). As a result, a new space, the cavum supracochleare, is formed between the pars cochlearis and tegmen tympani. The facial nerve pierces the primary side wall beneath the prefacial commissure via the facial canal in the internal acoustic meatus and enters the cavum supracochleare where the geniculate ganglion is located. In addition to its usage in the mammalian chondrocranium, the term tegmen tympani is also used in adult human anatomy for the “thin, translucent plate of bone [petrous temporal=petrosal]. . .forming the roof of the tympanic cavity” (Terry 1942:147) and is found in the Nomina Anatomica (1983) and Nomina Anatomica Veterinaria (1994). Applying the term in the adult is often complicated by late ontogenetic fusions between the tegmen tympani and the pars cochlearis. Following De Beer’s (1937) and Moore’s (1981) usage, the tegmen tympani in ventral view in AMNH 28272 includes the floor of the cavum supracochleare, which is produced forward as the spine beneath the hiatus Fallopii described above, and the adjacent parts of the facial sulcus and the sulcus for the stapedial artery (“tt” in Figs. 26B, 28). Dominating the posterior aspect of the pars canalicularis is the caudal tympanic process, which as stated above is a high, laminar, quadrangular element continuous anteromedially with the rostral tympanic process. The caudal tympanic process has two separate points of origin on the pars canalicularis (“ctpm(br)” and “ctpl(br)” in Fig. 28), which following MacPhee (1981) are termed the medial and lateral sections of the caudal tympanic process. MacPhee (1981) further recognized two types of lateral sections based on their position lateral or medial to the stapedius fossa; the lateral section of the caudal tympanic process in the solenodon is of the type medial to the stapedius fossa. The base of the medial section (“ctpm” in Fig. 26B) is situated about a millimeter posterior to the aperture of the cochlear fossula, is about 1.5 mm wide in AMNH 28272, and lies in a coronal plane. Extending anteroventrally from the base at about a 45º angle, the medial section is a quadrangular lamina about three millimeters high in AMNH 28272. Near its anteroventral terminus, the medial 1/6/09 9:25:26 AM 2008 Wible—On the Cranial Osteology of Solenodon paradoxus 363 Fig. 29.—Solenodon paradoxus, AMNH 185012, photographs of left ear region. A, oblique medial view; B, oblique posterior view. 1 = the laminar posterior part of the rostral tympanic process of petrosal; 2 = the medial section of the caudal tympanic process of petrosal; and 3 = the lateral section of the caudal tympanic process of petrosal. Scale = 2 mm. Abbreviations: bo, basioccipital; bs, basisphenoid; e, ectotympanic; egp, entoglenoid process; fn, aperture for facial nerve; gf, glenoid fossa; ips, inferior petrosal sinus; m, malleus (manubrium); mc, mastoid canaliculus; me, mastoid exposure of petrosal; oc, occipital condyle; pgf, postglenoid foramen; pp, paroccipital process of petrosal; ptc, posttympanic crest; ptp, posttympanic process; rtp, rostral tympanic process of petrosal; sh, stylohyal; sm, aperture for stapedius muscle tendon; tca, tympanic canaliculus; th, tympanohyal. section merges medially with the rostral tympanic process (described above) and laterally with the lateral section of the caudal tympanic process. The base of the lateral section (“ctpl” in Fig. 26B) is situated about a millimeter lateral to the aperture of the cochlear fossula on the crista interfenestralis (the bar of bone between the round and oval windows), is about a half millimeter wide in AMNH 28272, and lies obliquely posteromedial to anterolateral. Extending ventrally from the base, the lateral section is a near vertical quadrangular lamina about a millimeter high that merges with the medial section, as noted above. The base of the medial section of the caudal tympanic process is about a millimeter posterior and a millimeter dorsal to both the base of the lateral section and the base of the rostral tympanic process (Fig. 28). The separation of these tympanic processes at their bases produces two openings: a medial one (“mc” in Figs. 25, 26B, 29A) between the rostral tympanic process anteriorly, the pars canalicularis dorsally, and the medial section of the caudal tympanic process ventrally, and a lateral one between the lateral section of the caudal tympanic process anteriorly, the pars canalicularis dorsally, and the medial section ventrally. These two openings lead into the same space, between the aperture of the cochlear fossula and the medial section of the caudal tympanic process, and provide a passageway for two structures running between the jugular foramen and stylomastoid notch in MPIH 6863: the auricular ramus of the vagus nerve (also noted by McDowell 1958 and MacPhee 1981; “abX” in Fig. 27B) and the lateral head vein draining into the internal jugular vein. On the left side of AMNH 185012, the medial opening is divided by a thin bar into a smaller dorsal opening and larger ventral one (Fig. 29A). Based on MPIH 6863, the dorsal opening is for the auricular ramus of the vagus and the ventral one for the lateral head vein. Rather than a complete bar separating two openings, the right side of AMNH 185012, left side of CM 18069, and both sides of AMNH 212912 Wible.indd 363 have an incomplete bar with a figure eight-shaped medial opening; AMNH 28272 and the left side of AMNH 28271 merely have an oval medial opening. The passageway for the auricular ramus of the vagus is the mastoid canaliculus (NAV 1994). The anteroventral margin of the merged rostral and caudal tympanic processes contacts the posterior crus of the ectotympanic at a squamous suture, three millimeters long on the left side of AMNH 185012 (Fig. 25). The isolated ectotympanic of AMNH 28272 shows a distinct facet where it abuts the tympanic processes (“tpfc” in Fig. 31; see also McDowell 1958: fig. 5C, D). MacPhee (1981:216) reported that the suture between the ectotympanic and tympanic processes (his caudal tympanic process) for MPIH 6863 was “in the process of disappearing” and McDowell (1958) noted that fusion of these elements occurs in large solenodon skulls. The skulls examined here that preserve contact between the ectotympanic and tympanic processes show no indication of sutural fusion: the left sides of AMNH 28271 and 185012, the right side of CM 18069, and both sides of AMNH 212912. The left side of AMNH 185012 preserves part of the stylohyal in place (Figs. 25, 29) and the dorsal surface of that element has a small abutment with the medial section of the caudal tympanic process, near its suture with the ectotympanic. In addition to its fusion with the medial section of the caudal tympanic process and sutural relationship to the ectotympanic, the lateral section of the caudal tympanic process has an additional osseous contact with the tympanohyal, except in the juvenile AMNH 28272 where these elements are separated by a narrow gap (Fig. 26). In the older specimens, the lateral section is fused to the tympanohyal dorsomedial to the facet for the stylohyal on the left side of AMNH 28271 and on both sides of AMNH 185012 (Figs. 25, 29B) and 212912; this relationship is obscured by breakage on the right side of AMNH 28271 and bilaterally in CM 18069. 1/6/09 9:25:26 AM 364 Annals of Carnegie Museum Vol. 77 Lateral to the lateral section of the caudal tympanic process is the confluence of two spaces discussed above medial to the crista parotica, the stapedius fossa posteriorly and the facial sulcus anteriorly. Based on MPIH 6863, four structures pass through this confluence (Figs. 26C, 27B); positioned from dorsolateral to ventromedial these are the lateral head vein, the facial nerve, the tendon of the stapedius muscle, and the ramus posterior of the stapedial artery (“rp” in Fig. 26C). The course of the last has been described in detail for MPIH 6863 by MacPhee (1981) as leaving the stapedial artery medial to the fenestra vestibuli, running posteriorly in a groove along the anterolateral margin of the lateral section of the caudal tympanic process, and dividing into two branches: one to the stapedius muscle and the other leaving the stylomastoid notch to end in the auricle. With the exception of the juvenile AMNH 28272, weak laminar flanges derived from the lateral section of the caudal tympanic process medially and the crista parotica laterally serve to subdivide the confluence of the stapedius fossa and facial sulcus to segregate some of these four structures (Fig. 29B). AMNH 185012 and the right side of 212912 have flanges that meet to completely wall off a ventromedial foramen for the ramus posterior (not visible in the figures) and nearly meet to separate a central foramen for the stapedius tendon (“sm” in Fig. 29B) from a dorsolateral foramen for the lateral head vein and facial nerve (“fn” in Fig. 29B). The juvenile AMNH 28272 has a broad confluence with no indication of subdivision (Fig. 26); and this area is obscured in CM 18069, AMNH 28271, and the left side of AMNH 28271. At the posteromedial corner of the petrosal is the jugular incisure, the petrosal’s contribution to the anterolateral wall of the jugular foramen (“jf” in Figs. 25, 28, 29B). Within the jugular incisure, the petrosal is thick dorsoventrally and only slightly concave. The pars cochlearis and pars canalicularis meet at the incisure with the posterior border of the former marked by the opening into the cochlear canaliculus (for the perilymphatic duct and vein in MPIH 6863) barely visible near the dorsal limit of the petrosal in the middle of the incisure (not visible in ventral view). Posterolateral to the incisure, the pars canalicularis meets the exoccipital at a foliate suture, with the petrosal the concave member. Dorsal View (Figs. 20, 21A, C, 22).—The endocranial surface of the petrosal is only fully visible in the bisected skull AMNH 28271, the basis for the following. Two large apertures, the internal acoustic meatus and subarcuate fossa, dominate the endocranial surface and represent the principal elements in the pars cochlearis and pars canalicularis, respectively. The elliptical internal acoustic meatus is only recessed slightly from the endocranial surface of the pars cochlearis. A transverse crest (“tc” in Fig. 22), slightly more recessed than the meatus, delimits an inferior fossa, the foramen acusticum inferius (“fai” in Fig. 21C), from a superior fossa, the foramen acusticum superius. The distribution Wible.indd 364 of openings within these two fossae is similar to that in a newborn human (Terry 1942: fig. 137), which provides the basis for the terminology below. The foramen acusticum inferius is round and dominated by a deep, oval opening, the posterior half of which has numerous small foramina, the spiral cribriform tract (“sct” in Fig. 22), transmitting twigs of the cochlear nerve, and the anterior half has an elliptical foramen, the foramen centrale cochleare (“fcc” in Fig. 22), indicating the orifice of the canal of the modiolus. The foramen acusticum inferius has two additional smaller openings, a larger dorsal one and a smaller posterodorsal one, that are not as deeply recessed as that containing the spiral cribriform tract and central cochlear foramen. The dorsal foramen is the inferior vestibular area for nerves to the saccule (“iva” in Fig. 22); the posterodorsal foramen is foramen singulare for the nerve to the ampulla of the posterior semicircular canal (“fsi” in Fig. 22). The foramen acusticum superius is subdivided by a slightly recessed crest running perpendicular to the transverse crest into a larger round opening into the facial canal (“fac” in Figs. 21C, 22) and a smaller oval superior vestibular area with numerous small foramina for twigs of the nerve of the utricle (“sva” in Fig. 21C). Dorsal to the internal acoustic meatus is the subarcuate fossa (“saf” in Figs. 21C, 22), which housed the paraflocculus of the cerebellum. The aperture of the subarcuate fossa is nearly square with only slight curvature at the four angles. The posteromedial border of the aperture is formed by the crus commune, the conjoined anterior and posterior semicircular canals, and the dorsal and anterolateral borders by the anterior semicircular canal. The internal acoustic meatus and aperture of the subarcuate fossa are oriented differently; the former is directed dorsomedially whereas the latter is directed anteriorly and slightly medially. The aperture of the subarcuate fossa is constricted with respect to the fossa itself, except along the ventral border where the aperture and fossa are in the same plane. In the lateral wall of the fossa are half a dozen small foramina, transmitting venous blood based on MPIH 6863. Anterior to the aperture of subarcuate fossa is a thin, raised crest, the crista petrosa (“crp” in Figs. 21C, 22), which continues anteroventromedially to form the slightly raised anterior border of the internal acoustic meatus (equal to the prefacial commissure). The crista petrosa is the attachment of the tentorium cerebelli and, thus, delimits the middle cranial fossa in front from the caudal cranial fossa behind. Anterior to the crista petrosa is the narrow, near vertical petrosal contribution to the posterior wall of the middle cranial fossa. Based on MPIH 6863, this faintly concave surface housed the back of the cerebrum. The majority of this surface is pars canalicularis with the ventral end the tegmen tympani (“tt” in Fig. 22). The anterior face of this surface abuts the squamosal; the ventral half of the petrosquamous suture is plane and the dorsal half foliate. Running the length of the dorsal margin of the pars canalicularis is the petrosal’s contribution to the sulcus for 1/6/09 9:25:26 AM 2008 Wible—On the Cranial Osteology of Solenodon paradoxus the sigmoid sinus and anterior to that the petrosal’s contribution to the canal for the prootic sinus (both described above with the Parietal; Fig. 21C). Between the sulcus for the sigmoid sinus and the crus commune is the aqueductus vestibuli for the endolymphatic duct and vein based on MPIH 6863 (“av” in Figs. 21C, 22). This aperture is dorsally directed and hidden in medial view by an irregular, low process in AMNH 28271. The sulcus for the sigmoid sinus bends ventrally posterior to this process and ends at the condyloid canals in the exoccipital (Fig. 21C). MPIH 6863 has some venous blood exiting the jugular foramen as the internal jugular vein; sections posterior to this with the condyloid canals are not preserved. However, based on the size of the condyloid canals in AMNH 28271, they represent the primary drainage for the sigmoid sinus. Most of the posterior margin of the pars canalicularis contacts the exoccipital at a squamous suture, but based on AMNH 28272, there is also a narrow contact with the supraoccipital (see Fig. 21C). Squamosal View.—As noted above, much of the squamosal surface is visible in the juvenile AMNH 28272, because of an artificial separation between the petrosal and squamosal bones, more so on the right side than left. However, the separation is not wide enough to allow illustration of the squamosal surface. Nevertheless, the exposed squamosal surface of the pars canalicularis is remarkably similar to that of some extant didelphid marsupials, such as Metachirus nudicaudatus (É. Geoffroy, 1803), AMNH 72551 illustrated in Sánchez-Villagra and Wible (2002: fig. 5c; this figure is erroneously attributed to Marmosa murina (Linnaeus, 1758), AMNH 99980 in the figure legend) and re-illustrated here (Fig. 30). As in M. nudicaudatus, the squamosal surface of the solenodon pars canalicularis has two principal parts: a broader posterior part overlaid by the squamosal bone and a narrower anterior part not in direct contact with the squamosal bone. The surface of the posterior part of the squamosal surface of the juvenile solenodon pars canalicularis is convex dorsoventrally, and its posterior margin is thickened ventrally, representing the base of the paroccipital process. Near the middle of the posterior part in M. nudicaudatus is a longitudinal posttemporal sulcus (“pts” in Fig. 30), which accommodates the arteria and vena diploëtica magna based on personal observations (Wible 1990, 2003) of Didelphis marsupialis Linnaeus, 1758 and Monodelphis domestica (Wagner, 1842). In other M. nudicaudatus with the petrosal in place, some (e.g., AMNH 96621) have a posttemporal foramen between the squamosal and mastoid exposure of the petrosal transmitting the posttemporal vessels to the occiput and others (e.g., CM 52728) do not. The juvenile solenodon also has a shallow posttemporal sulcus, less than half a millimeter in width, but only on the caudal half of the posterior part (the incidence of the posttemporal foramen is considered with the Mastoid view). Based on MPIH 6863, the primary occupant of the juvenile solenodon posttemporal sulcus is venous; this specimen has Wible.indd 365 365 Fig. 30.—Metachirus nudicaudatus, AMNH 72551, right petrosal in lateral view, redrawn from Sánchez-Villagra and Wible (2002: fig. 5c; this figure was attributed erroneously to Marmosa murina, AMNH 99980, in the figure legend). Abbreviations: cp, crista parotica; fc, fenestra cochleae; fv, fenestra vestibuli; hF, hiatus Fallopii; prc, prootic canal; pts, posttemporal sulcus; rtp, rostral tympanic process of petrosal; sps, sulcus for prootic sinus; tgf, trigeminal ganglion fossa; th, tympanohyal. a tiny arteria diploëtica magna arising from the ramus superior dorsal to the piriform fenestra and well-developed accompanying veins. The surface of the anterior part of the squamosal surface of the pars canalicularis in M. nudicaudatus has a near vertical sulcus for the prootic sinus (“sps” in Fig. 30), the anterior distributary of the transverse sinus in marsupials and monotremes (Wible 1990, 2003; Wible and Hopson 1995), at the ventral end of which is a small lateral aperture of the prootic canal (“prc” in Fig. 30). The intact squamosal bone contributes more surface area to the sulcus for the prootic sinus, but does not fully enclose a canal. The juvenile solenodon AMNH 28272 has the same arrangement, although the single lateral aperture of the prootic canal is more centrally placed in the ventral end of the sulcus for the prootic sinus; a probe passed through this aperture reaches both of the tympanic apertures of the prootic canal described above. The adult solenodon, based on the bisected skull AMNH 28271, exhibits a major difference from both the juvenile and M. nudicaudatus. Rather than the lateral aperture of the prootic canal opening directly into the prootic sinus as in the juvenile and M. nudicaudatus, the squamosal in the adult has an additional thin layer of bone that encloses a second lateral aperture of the prootic canal within the squamosal appressed to the opening within the petrosal. In summary, the prootic sinus in the adult solenodon runs ventrally in an anteromedially open sulcus between the squamosal and pars canalicularis (Fig 21C); dorsal to the postglenoid foramen the sulcus is entirely within the squamosal. In the posteromedial aspect of this squamosal sulcus is a lateral aperture of the prootic canal in the squamosal leading into the prootic canal within the pars canalicularis. 1/6/09 9:25:27 AM 366 Annals of Carnegie Museum Vol. 77 Fig. 31.—Solenodon paradoxus, AMNH 28272, drawings of left ectotympanic and broken rostral process of malleus. A, ventral (extratympanic) view; B, dorsal (intratympanic) view. Abbreviations: acr, anterior crus; at, sulcus for auditory tube; ct, crista tympanica; pcr, posterior crus; pep, petrosal process of rostral process of malleus; rpm, rostral process of malleus; sp, styliform process; st, sulcus tympanicus; ti, tympanic incisure; tpfc, tympanic process of petrosal facet. Mastoid View (Figs. 34, 35).—The exposure of the pars canalicularis on the occiput, the mastoid exposure, is roughly trapezoidal. The medial and dorsal borders are subequal and long, whereas the lateral and ventral are subequal and short. The medial border is near vertical and has a squamous suture with the exoccipital, based on AMNH 28272, which preserves a suture between the ex- and supraoccipital (Fig. 35). The dorsal border is oblique, following the contour of the nuchal crest; from dorsomedial to ventrolateral, it overlaps the supraoccipital, based on AMNH 28272 (Fig. 35), and has squamous sutures with the parietal and the squamosal. The lateral border, the paroccipital process, is near vertical and has a squamous suture with the posttympanic process of the squamosal; it forms the raised medial edge of a muscular depression on the posterior face of the posttympanic process. The ventral border has a central concavity, which includes the posterior face of the lateral semicircular canal, flanked by the paroccipital process laterally and the medial section of the caudal tympanic process medially. Based on MPIH 6863, the lateral border, paroccipital process, provides attachment for the common tendon of the sternomastoideus and cleidomastoideus of Allen (1910), Wible.indd 366 which arises primarily from the depression on the backside of the posttympanic process of the squamosal. Also based on MPIH 6863, the ventral end of the paroccipital process marks the lateral limit of a broad sheet of musculature that medially reaches the medial section of the caudal tympanic process and exoccipital; as noted by Thiel (1955) this sheet includes the posterior digastric and mastoideohyoideus (mastoideostyloideus of Saban 1968). In the two longest skulls, AMNH 28271 and 212912, the posterior face of the posterior semicircular canal is raised from the surface of the mastoid exposure dorsal to the medial section of the caudal tympanic process. Small foramina penetrate the mastoid surface in all specimens (“msf” in Fig. 34) except the juvenile AMNH 28272 and the left side of AMNH 212912. Most are along the dorsal border near the suture with the squamosal: AMNH 185012 and 212912 right side only; AMNH 28271 and CM 18069 bilaterally. The left side of AMNH 185012 and right side of AMNH 28271 have a more dorsomedially placed foramen, near the suture with the parietal. These openings do not lead into a posttemporal canal between the pars canalicularis and squamosal and, therefore, are not posttemporal foramina, but are identified as mastoid foramina. Gregory (1910; 1/6/09 9:25:28 AM 2008 Wible—On the Cranial Osteology of Solenodon paradoxus “?f.p.m.” in Fig. 1) and McDowell (1958) noted a small foramen on the lateral mastoid surface of AMNH 28272 that they thought might be a mastoid foramen (their post-mastoid foramen), but this is a slit rather than a foramen related to the juvenile nature of the growing petrosal bone. Ectotympanic (“e” in Figs. 11, 18, 24, 25, 31) The C-shaped ectotympanic is preserved in situ bilaterally in AMNH 212912, the left side of AMNH 28272 and 185012, and the right side of AMNH 28271 and CM 18069 (Figs. 11, 12). McDowell (1958: fig. 5C, D) figured external and internal views of a left ectotympanic (his tympanic) for an unspecified S. paradoxus, but this element is from a specimen other than AMNH 28272, because the latter bone was preserved in situ at the beginning of this project (Fig. 18) but subsequently fell off (Fig. 19). In addition, the right ectotympanic in CM 18069 was removed for this study. Here the isolated elements are described first, followed by those preserved in situ. Referring to Figure 31, the maximum dimension of the isolated left ectotympanic of the juvenile AMNH 28272 and the right of CM 18069 is roughly 5 mm, from the styliform process (“sp” in Fig. 31) to the distal end of the anterior crus (“acr” in Fig. 31); the dimension perpendicular to that is roughly 4 mm, from the anterior surface of the anterior crus to the posterior surface of the posterior crus (“pc” in Fig. 31). The anterior crus is fairly straight, whereas the posterior crus is more curved, even hook-like at its distal end; the tympanic incisure, the gap between the distal ends of the anterior and posterior crura, is less than a millimeter (“ti” in Fig. 31). The anterior face of the anterior crus is flat except where it is crossed by a millimeter wide, obliquely-oriented (from dorsolateral to ventromedial) groove housing the rostral process of the malleus. The groove is well shown in McDowell’s (1958: fig. 5C, D) illustrations, but is occupied by the rostral process of the malleus in AMNH 28272 (“rpm” in Fig. 31) and CM 18069. The rostral process is partially fused to the anterior crus in both specimens and broke from the rest of the malleus, which in the case of AMNH 28272 is missing. The anterior face of the anterior crus is also of uniform height except at its distal end where it tapers to a rod-like prong. The anteromedial corner of the ectotympanic has a short, trapezoidal styliform process (Klaauw 1931; =anteromesial spine of McDowell 1958 or anterior process of MacPhee 1981), which is slightly more robust in CM 18069. The dorsal surface of the styliform process has a faint sulcus (“at” in Fig. 31B), which based on MPIH 6863 floors the auditory tube. The proximal half of the posterior crus in AMNH 28272 and proximal two-thirds in CM 18069 are smooth and uniform in width (Fig. 31). However, the distal part bears a concave facet on its posterior surface (“tpfc” in Fig. 31) for the ectotympanic’s abutment with the conjoined rostral and caudal tympanic processes of the petrosal described above. In AMNH 28272, the bone around the Wible.indd 367 367 facet is broader than the proximal posterior crus, whereas in CM 18069 it is narrower. The size of the facet varies in the other specimens: it is about half the posterior crus in AMNH 212912, but two-thirds of it in AMNH 27271 and 185012. The inner margin of the ectotympanic has a well-developed sulcus tympanicus (“st” in Fig. 31B) except at the distal tips of both the anterior and posterior crurae; only the middle portion of the sulcus is visible in dorsal view. Based on MPIH 6863, the sulcus tympanicus is the point of attachment of the tympanum. Forming the dorsal margin of the sulcus tympanicus is a low semicircular ridge, the crista tympanica (“ct” in Fig. 31B). McDowell (1958) noted the presence in solenodon of a recessus meatus, “the most proximal part of the bony external auditory meatus, set off from the meatus proper by its broader diameter” (McDowell 1958:128). The recessus meatus (“rem” in Fig. 31B) is the narrow gap between the sulcus tympanicus and the ventralmost margin of the ectotympanic. The ectotympanic bones preserved in situ (AMNH 212912, the right side of AMNH 28271, and the left side of AMNH 185012) provide information about the contacts of the tympanic ring with the skull base. The anterior crus abuts the posteromedial base of the entoglenoid process of the squamosal (Figs. 12, 25), occupying a facet described above (“efc” in Fig. 25). The posterior crus abuts the conjoined rostral and caudal tympanic process of the petrosal, the tympanohyal, the posttympanic crest of the squamosal, and the stylohyal in the two instances part of that element is preserved (left side of AMNH 185012 and 212912). MacPhee (1981) reported the inclination of the right and left ectotympanic of MPIH 6863 to be 40º from the horizontal plane of the basicranium. The angle in the three skulls preserving ectotympanics in situ varies: 34º bilaterally in AMNH 212912, 43º on the left side of AMNH 185012, and 46º on the left side of AMNH 28272. The different values may result from differences in developmental stage, but a larger sample is needed to address that. Auditory Ossicles Malleus (Fig. 32).—The right malleus of CM 18069 was removed in two pieces with some damage at their point of union. The malleus is also preserved in situ bilaterally in AMNH 212912 and on the right of AMNH 185012. The malleus in Figure 32 is based on CM 18069 with the damaged portion completed from the other three elements in AMNH 185012 and 212912. The basic parts of the malleus are the head, neck, manubrium, osseous lamina, and rostral (anterior) process. The head (“hm” in Fig. 32B) bears two articular surfaces for the incus set off from each other at an angle of 110º. The much larger superior (anterior) articular facet is flat and oval, whereas the inferior (posterior) articular facet is triangular and strongly convex (“suaf” and “iaf” in Fig. 32B). The anteroventral border of the head is delimited by a weak capitular crest with a capitular spine (“cs” in Fig. 32B). 1/6/09 9:25:28 AM 368 Annals of Carnegie Museum Vol. 77 Fig. 32.—Solenodon paradoxus, CM 18069, right malleus (rostral process broken and reconstructed based on AMNH 185012 and 212912). A, dorsal view shaded drawing; B, dorsal view line drawing; C, ventral view line drawing. Abbreviations: cb, central buttress; cs, capitular spine; fct, foramen for chorda tympani nerve; gct, groove for chorda tympani nerve; hm, head; iaf, inferior articular surface; ila, inner longitudinal lamella; lp, lateral process; mn, manubrium; mnb, manubrial base; mptt, muscular process for tensor tympani; nm, neck; oa, orbicular apophysis; ol, osseous lamina; ola, outer longitudinal lamella; pep, petrosal process of rostral process of malleus; suaf, superior articular facet. Wible.indd 368 1/6/09 9:25:32 AM 2008 Wible—On the Cranial Osteology of Solenodon paradoxus The neck (“nm” in Fig. 32B) runs posteriorly from the posterior aspect of the head and turns medially and ventrally to the base of the manubrium. Just before achieving the manubrial base, the neck is crossed by the groove for the chorda tympani nerve on its dorsal aspect (“gct” in Fig. 32B). Immediately lateral to the groove for the chorda tympani is the large, digitiform muscular process for the attachment of the tensor tympani muscle based on MPIH 6863 (“mptt” in Fig. 32B). The base of the manubrium (“mnb” in Fig. 32B) is at the confluence of the neck, orbicular apophysis, lateral process, and manubrium. The prominent orbicular apophysis (“oa” in Fig. 32B, C) projects posteriorly from the manubrial base. The lateral process is on the ventral aspect of the manubrial base (“lp” in Fig. 32C) and marks the lateral limit of the tympanum attachment to the manubrium. The manubrium (“mn” in Fig. 32B, C) is fully preserved only on the left sides of AMNH 185012 (Fig. 29A) and 212912; it is flattened anteroposteriorly and tapers to its tip, which is slightly more spatulated in the former specimen. In both specimens, the manubrium is only slightly less inclined than the ectotympanic from the horizontal basicranial plane. Its tip is not straight, but has a slight ventral curvature (Fig. 29A). Anterior to the manubrial base and muscular process and medial to the head is the roughly quadrangular osseous lamina (“ol” in Fig. 32B, C). The osseous lamina is paper thin and transparent; it is convex on its dorsal aspect and deeply concave ventrally, which sets the lamina off distinctly from the head. The groove for the chorda tympani nerve described above on the neck continues forward along the dorsal aspect of the osseous lamina. The lateral margin of the groove is marked by a distinct ridge extending forward from the muscular process; this ridge is the central buttress (“cb” in Fig. 32B); there is no indication of the central buttress on the ventral aspect of the osseous lamina (Fig. 32C). The anterior margin of the osseous lamina is marked by a raised ridge on the dorsal and ventral aspects: the inner lamella dorsally (“ilm” in Fig. 32B) and outer lamella ventrally (“olm” in Fig. 32C). These lamellae connect the head to the well-developed rostral process. The medial margin of the osseous lamina is not thickened to form a pars processus anterioris. The rostral process (“rpm” in Fig. 32B, C) lies perpendicular to the head and in situ extends anteroventrally between the anterior surface of the ectotympanic’s anterior crus and the posterior surface of the entoglenoid process of the squamosal, occupying facets on both bones (Figs. 25, 31). The rostral process is anteroposteriorly flat and tapers to a point at its anteroventral end. Where the posterior surface of the rostral process meets the dorsal aspect of the osseous lamina is the foramen for the chorda tympani nerve (“fct” in Fig. 32B, C), transmitting the nerve through the rostral process to a groove on the posterior face of the entoglenoid process (“gct” in Figs. 25, 26B). Projecting posterodorsally from the dorsal edge of the rostral process is a distinct ovoid process, called here the petrosal process Wible.indd 369 369 of the rostral process (“pep” in Fig. 32B), that contacts a facet on the crista parotica (“mfc” in Fig. 26B). When the malleus was removed from CM 18069, connective tissue held these elements in articulation. MPIH 6863 preserves this contact, with no indication of a synovial joint. Incus (Fig. 33A, B).—The left incus was removed from CM 18069 for study and illustration; the right incus is preserved in situ in CM 18069 unobstructed by the malleus, which was removed for this study. The incus is preserved in situ bilaterally in AMNH 212912, but most of it is hidden by the malleus and ectotympanic. The basic parts of the incus are the body, crus breve (short process), crus longum (long process), and the lenticular process. The body (“bi” in Fig. 33A) bears two articular surfaces for the malleus; the larger superior articular surface is oval and flat (“sas” in Fig. 33B), whereas the inferior articular surface is triangular and strongly concave (‘ias” in Fig. 33A, B). The crus breve (“cb” in Fig. 33A) is short and cylindrical, projects posterodorsally from the body into the fossa incudis in the petrosal part of the epitympanic recess, and is attached there by the posterior ligament of the incus. The crus longum (“cl” in Fig. 33A, B) extends posteriorly and slightly ventrally and laterally from the body towards the stapes; it lies roughly in the same plane as the neck of the malleus, which it is dorsal to and separated from by a narrow gap. The crus longum tapers slightly at its distal end, turns medially at a right angle, and is connected to the flat, oval lenticular process (“lpr” in Fig. 33A, B) by a narrow pedicle (“ped” in Fig. 33B). Stapes (Fig. 33C).—Stapes are preserved in situ bilaterally in AMNH 212912. The presence of the ectotympanic, malleus, and incus in this specimen partially obscures the head and footplate of the stapes, but a reconstruction of the left stapes was made (Fig. 33C). The stapes includes a head, anterior and posterior crurae, and footplate. The head (“hs” in Fig. 33C) articulates with the lenticular process of the incus at the incudostapedial joint and appears to be roughly of the same shape and dimension. The head blends with the merged anterior and posterior crurae (“acr” and “pcr” in Fig. 33C), separated from each by an expansion, the shoulder of the anterior and posterior crurae (“acs” and “pcs” in Fig. 33C). On the shoulder of the posterior crus is a small, posteriorly directed muscular process for the insertion of the stapedius muscle based on MPIH 6863 (“mps” in Fig. 33C). From the shoulders, the anterior and posterior crurae bow outward and then inward to similar extents before connecting to the footplate (“fp” in Fig. 33C), which occupies the fenestra vestibuli on the petrosal promontorium. The space outlined by the shoulders, crurae, and footplate is the stapedial (intracrural) foramen (“stf” in Fig. 33C), through which the stapedial artery passes based on MPIH 6863. The anterior crus is uniformly narrow, whereas the posterior crus is expanded at the footplate end. Both the 1/6/09 9:25:33 AM 370 Annals of Carnegie Museum Vol. 77 Fig. 33.—Solenodon paradoxus, CM 18069, drawings of left incus and stapes. A, left incus, oblique lateral view; B, left incus, oblique ventral view; C, left stapes, slightly oblique anteroventral view. Abbreviations: acr, anterior crus; acs, shoulder of anterior crus; bi, body; cb, crus breve; cl, crus longum; crs, crural sulcus; cst, crista stapedis; fp, footplate; hs, head of stapes; ias, inferior articular surface; lpr, lenticular process; mps, muscular process for stapedius muscle; pcr, posterior crus; pcs, shoulder of posterior crus; ped, pedicle; sas, superior articular surface; stf, stapedial foramen. anterior and posterior crurae have a crural sulcus facing the stapedial foramen, but only the sulcus on the posterior crus is visible in the figure because of the slightly oblique view (“crs” in Fig. 33C). The edges delimiting the crural sulci extend across the tympanic surface of the footplate as a paired, low crista stapedis (“cst” in Fig. 33C). Wible.indd 370 Occipital Complex The occipital complex contributes to the basicranium, occiput, braincase roof, and the caudal cranial fossa. Based on MPIH 6863 and AMNH 28272, the occipital complex comprises four ossifications: the median basioccipital on 1/6/09 9:25:34 AM 2008 Wible—On the Cranial Osteology of Solenodon paradoxus the skull base, the paired exoccipital posterolateral to the basioccipital on the skull base and on the occiput, and the median supraoccipital dorsal to the foramen magnum on the occiput and on the braincase roof. MPIH 6863 is the only specimen delimiting the basioccipital and exoccipitals, and AMNH 28272 is the only specimen delimiting the exoccipitals and supraoccipital (Fig. 35). The individual components of the occipital complex are described based on the sutural positions in MPIH 6863 and AMNH 28272. Basioccipital (“bo” in figures) The basioccipital occupies the midline of the basicranium posterior to the basisphenoid, medial to the pars cochlearis of the petrosal, and anterior to the foramen magnum (“fm” in Fig. 25). The basioccipital is fused to the exoccipitals in all skulls examined (Figs. 11, 12, 18, 25, 26A, B), but these ossification centers are separated by cartilage in MPIH 6863. In the juveniles AMNH 28272 and 185012, the basioccipital is separated from the basisphenoid by a narrow transverse gap, the open spheno-occipital synchondrosis, at the level of the anterior limit of the rostral tympanic process of the petrosal (Figs. 25, 26A, B); in the adults, the basioccipital and basisphenoid are fused (Fig. 12). The lateral contact with the pars cochlearis of the petrosal is described above. As interpreted from MPIH 6863, the posterolateral limit of the basioccipital is at the anterior end of the jugular foramen (“jf” in Fig. 25). The basi- and exoccipital juncture then runs obliquely posteromedially to the anteromedial rim of the foramen magnum. The odontoid notch (intercondyloid incisure of Evans 1993; “on” in Fig. 25) and part of the adjacent occipital condyles (“oc” in Fig. 25) are on the basioccipital, although the exact extent is not known. Ventral surface features of the basioccipital differ across the age range examined. In the juvenile AMNH 28272 (Fig. 18), the entire surface is relatively flat; immediately anterior to the occipital condyles are faint ovoid depressions for the rectus capitis ventralis based on MPIH 6863. In the older juvenile AMNH 185012 (Figs. 11, 12), the central third of the anterior half is convex and flanked by concavities for the longus capitis based on MPIH 6863; the ovoid depressions for the rectus capitis ventralis are more pronounced. The adult CM 18069 (Fig. 12) differs in that it has a midline keel in the anterior half, rather than a rounded eminence, that extends anteriorly onto a fainter midline keel on what positionally must be the posterior half of the basisphenoid, these two bones being fused. Finally, the longest adult skull, AMNH 212912 (Fig. 12), differs in that the midline keel on the basioccipital and basisphenoid is more pronounced and there is a pronounced obliquely oriented muscular tubercle on either side of the keel at or near the juncture of the basioccipital and basisphenoid. Based on MPIH 6863, this process is for the longus capitis, because that muscle arises from the basioccipital, basisphenoid, and the spheno-occipital synchondrosis. Wible.indd 371 371 The odontoid notch also differs with age. In the juveniles AMNH 28272 and 185012, the odontoid notch is shallow and without facets (Figs. 11, 12, 18). In the adult CM 18069 (Fig. 12), the notch is deeper and with faint facets for the odontoid process of the axis facing posteromedially on the posteromedial face of the occipital condyles; the left and right facet come within a millimeter of each other and are a millimeter at their thickest. Finally, in the longest adult skull, AMNH 212912 (Fig. 12), the facets are more pronounced, within a half millimeter of each other and nearly two millimeters at their thickest. In AMNH 28271 (Figs. 20, 21A, C), the endocranial surface of the basioccipital on the right side is essentially flat except anteriorly where it appears to contribute to the shallow hypophyseal fossa (see Basisphenoid); most of the basioccipital is missing from the left side (Fig. 21C). A dorsum sellae and posterior clinoid processes are lacking. Exoccipital (“eo” in figures) The paired exoccipital has two quadrangular parts: a horizontal one in the skull base (Fig. 25) and a vertical one in the occiput (Fig. 35); both contribute to the closure of the foramen magnum and to the occipital condyles. The exoccipitals are fused to the basioccipital in all skulls (Fig. 12) and to the supraoccipital in all (Fig. 34) except AMNH 28272 (Fig. 35). The anteromedial border of the exoccipital’s horizontal part with the basioccipital is described above. The oblique lateral border includes the exoccipital’s contribution to the walls of the jugular foramen in front and the foliate suture with the pars canalicularis of the petrosal behind. At this suture with the petrosal, the edge of the exoccipital is slightly raised (“pcop” in Figs. 25, 27A), more so in the adults (Fig. 12); in MPIH 6863 this faint process provides attachment for the rectus capitis lateralis and the broad sheet of musculature that includes the mastoideohyoideus and posterior digastric. In the dog (Evans 1993), the stout jugular (paracondylar) process of the exoccipital has attachment for the same muscles (mastoideohyoideus=jugulohyoideus), and, therefore, the solenodon eminence is identified as a very weak paracondylar process. The posterior border of the exoccipital’s horizontal process is on the free posterior edge of the skull base; it is formed by the occipital condyle and a depression between the condyle and the faint paracondylar process, the ventral condyloid fossa (“vcof” in Fig. 25). The posteromedial border is the foramen magnum. Between the occipital condyle and jugular foramen are the hypoglossal foramina (“hf” in Figs. 25, 26B), which are paired except for the right side of AMNH 185012, which has three. The position and size of the paired foramina varies: they are subequal with the posterior one slightly lateral to the anterior one in AMNH 28271, 28272, and 185012 (left side); subequal with the anterior one slightly lateral to the posterior one in AMNH 212912 (left side); and the anterior one smaller and slightly lateral to the posterior 1/6/09 9:25:34 AM 372 Annals of Carnegie Museum Vol. 77 Fig. 34.—Solenodon paradoxus, AMNH 185012, drawings of skull in occipital view. Abbreviations: bcf, basicapsular fissure; bo, basioccipital; ctp, caudal tympanic process of petrosal; dcf, dorsal condyloid foramen; e, ectotympanic; egp, entoglenoid process; eo, exoccipital; eoc, exoccipital crest; me, mastoid exposure of petrosal; msf, mastoid foramen; nc, nuchal crest; oc, occipital condyle; pa, parietal; pet, petrosal; pp, paroccipital process of petrosal; ptp, posttympanic process; rt, foramina for rami temporales; rtp, rostral tympanic process of petrosal; sc, sagittal crest; sh, stylohyal; so, supraoccipital; soc, supraoccipital crest; socf, supraoccipital foramina; sq, squamosal; zpsq, zygomatic process of squamosal. one in AMNH 212912 (right side) and CM 18069. The hypoglossal foramina open into a common depression in CM 18069 and AMNH 28271, 212912, and 185012 (right side), whereas a common depression is lacking on the left side of AMNH 185012 and both sides of AMNH 28272 (see Fig. 25). The posterior hypoglossal foramen shares a common depression with one or more openings that connect to the condyloid canal (described below with the endocranial surface of the exoccipital) in AMNH 28271, 185012, 212912, and CM 18069, whereas the anterior hypoglossal foramen shares a common depression with such Wible.indd 372 openings in AMNH 28271 and 28272. The shallow ventral condyloid fossa lies posterior to the hypoglossal foramina and contains a variable number of small to large-sized foramina that connect to the condyloid canal (“vcf” in Fig. 26B). The fewest ventral condyloid foramina are the two small ones on the left side of AMNH 185012 and the most the seven small ones on the left side of AMNH 212912. Along with several small openings, AMNH 28271 has bilateral large openings that are a millimeter and a half in maximum diameter. The vertical process of the exoccipital (Fig. 35) has a 1/6/09 9:25:35 AM 2008 Wible—On the Cranial Osteology of Solenodon paradoxus 373 Fig. 35.—Solenodon paradoxus, AMNH 28272, photograph and line drawing of skull in occipital view. Abbreviations: as, alisphenoid; bo, basioccipital; bs, basisphenoid; ctp, caudal tympanic process of petrosal; dcf, dorsal condyloid foramen; egp, entoglenoid process; eo, exoccipital; fm, foramen magnum; ham, pterygoid hamulus; hf, hypoglossal foramina; me, mastoid exposure of petrosal; nc, nuchal crest; oc, occipital condyle; pet, petrosal; pp, paroccipital process of petrosal; ptp, posttympanic process; so, supraoccipital; socf, supraoccipital foramina; sq, squamosal; th, tympanohyal; tpas, tympanic process of alisphenoid; zpsq, zygomatic process of squamosal. near vertical lateral suture with the pars canalicularis described above and a sinuous foliate suture with the supraoccipital dorsally. Its medial and ventral edges are free; the former forms the lateral margin of the foramen magnum and the latter is the occipital condyle and ventral condyloid fossa. At the lateral suture with the pars canalicularis, the exoccipital has a raised crest (“eoc” in Fig. 34), more pronounced in the adults, that is continuous ventrally with the faint paracondylar process and dorsally with a more Wible.indd 373 pronounced crest on the supraoccipital described below. Following Gaudin (1995), this is identified as an exoccipital crest. Immediately dorsal to the occipital condyle is a shallow dorsal condyloid fossa. In the medial margin of the dorsal condyloid fossa are openings into the condyloid canal that vary in size and number (“dcf” in Figs. 34, 35). AMNH 185012 (right side), 212912, and CM 18069 (left side) have a single large opening; AMNH 28271, 28272 1/6/09 9:25:36 AM 374 Annals of Carnegie Museum Vol. 77 (left side), 185012 (left side), and CM 18069 (right side) have large and small openings; and AMNH 28272 (right side) has a large and two small openings. Two specimens, AMNH 212912 and CM 18069, also have an additional small opening to the condyloid canal just anteromedial to the ventral condyloid fossa on the endocranial side of the foramen magnum. As McDowell (1958:145) noted, the solenodon occipital condyle has two facets joined by a narrow isthmus of bone: “one ventral and anterior to the foramen magnum and another lateral to the foramen magnum and facing backward.” The larger posterodorsal facet (Figs. 34, 35) is more uniform in shape across the examined specimens; its main axis is oblique, from posteroventromedial to anterodorsolateral. In occipital view it is cylindrical and in ventral view elliptical. The smaller anteromedial facet is labial-shaped in the juveniles (Figs. 11, 18, 25, 26), but is more quadrangular in the adults (Fig. 12). Reflecting the external surfaces, the endocranial surface of the exoccipital in AMNH 28271 has horizontal and vertical components contributing to the floor and posterior wall of the caudal cranial fossa (Fig. 21C). At the lateral margin of the horizontal component are the two hypoglossal foramina (Fig. 21C; three on the right side of AMNH 185012), visible in all specimens through the foramen magnum (Fig. 35). At the anterior margin of the vertical component in the terminus of the sigmoid sinus sulcus in AMNH 28271 are several large openings into the condyloid canal (“coca” in Figs. 21C, 22), which runs posteriorly through the exoccipital to the ventral and dorsal condyloid foramina described above. The left side of AMNH 28271 has a large opening subdivided by a thread-like septum and the right side has three large and two small openings. Sections preserving the condyloid canal are not preserved for MPIH 6863. McDowell (1958) described the condyloid canal in solenodon as venous, which is the case in the ox (Sisson 1910) and dog (Evans 1993). Supraoccipital (“so” in figures) The supraoccipital forms the dorsal half of the occiput and contributes to the posteriormost margin of the braincase roof. The juvenile AMNH 28272 is the only skull fully delimiting the borders of the supraoccipital (Figs. 5, 35); the older juvenile AMNH 185012 preserves only the anterior sutures with the parietals and interparietal (described above; Fig. 2). On the occiput, the supraoccipital has an irregular ventral border and a longer curved dorsal border that is the nuchal crest (“nc” in Fig. 35). The middle third of its ventral edge forms the dorsal margin of the foramen magnum and the lateral thirds contact the exoccipitals (see above). The adults AMNH 212912 and CM 18069 have a midline external occipital crest that extends about halfway down from the nuchal crest (the midline is not preserved in AMNH 28271); in the juveniles this area is flat in AMNH Wible.indd 374 28272 (Fig. 35) and slightly convex in AMNH 185012 (Fig. 34). At the lateral margin of the supraoccipital is a triangular depression dorsal to the pars canalicularis delimited by medial and lateral ridges that unite dorsally, except in AMNH 28272 where the bone is featureless. The medial ridge (“soc” in Fig. 34) is continuous ventrally with the exoccipital crest (and the faint paracondylar process) and is termed the supraoccipital crest here. The lateral ridge is on the nuchal crest; the dorsal half of the lateral ridge is formed entirely by supraoccipital, whereas the ventral half has a contribution from the parietal, based on AMNH 185012. All specimens have supraoccipital foramina (“socf” in Figs. 34, 35) that connect internally to the occipital emissary vein described above (see Parietal), but the number, size, and position vary both between and within specimens. AMNH 28272 has a centrally positioned heart-shaped depression that contains a half dozen smaller openings (Fig. 35); AMNH 185012 has two larger openings per side, well off the midline, and a number of smaller openings (Fig. 34); AMNH 212912 and CM 18069 have an ovoid depression just to the left of the external occipital crest that contains several smaller openings as well as an additional dozen small openings arrayed across the occiput. On the braincase roof, the supraoccipital has a narrow exposure with sutures anteriorly with the interparietal and parietals described above (Figs. 2, 5). Where the occipital and dorsal surfaces of the supraoccipital meet is the nuchal crest. In dorsal view, the nuchal crest is evenly convex in AMNH 28272 (Fig. 5), with a slight midline concavity in AMNH 185012 (Figs. 2, 4), and with a more pronounced midline concavity in AMNH 212912 and CM 18069 (Fig. 4). In lateral view, the dorsal and occipital surfaces meet at roughly a right angle in AMNH 28272, but in the remaining skulls the nuchal crest overhangs the occiput (Fig. 8). Sutures delimiting the supraoccipital within the caudal cranial fossa are visible through the foramen magnum in the juvenile AMNH 28272 (see Fig. 21C). The middle third of the supraoccipital’s contribution to the endocranial roof reflects that bone’s external exposure on the braincase roof, because of the edge-to-edge nature of the suture with the interparietals. In contrast, the lateral thirds of the supraoccipital’s endocranial roof contribution are more substantial than the corresponding braincase roof contribution, because the parietals broadly overlap the supraoccipital externally. The middle third of the supraoccipital’s endocranial roof contribution has a depression for the vermis of the cerebellum that extends anteriorly onto the interparietals and posteroventrally onto the endocranial side of the supraoccipital’s occiput contribution. The lateral thirds have an impression for the back of the cerebrum that extends anteriorly but is much fainter on the interparietal. The lateral margin of the supraoccipital’s roof contribution abuts the posterodorsal corner of the pars canalicularis of the petrosal. In the bisected skull AMNH 28271, the endocranial surface of the supraoccipital differs in one major regard, the presence of a wide sulcus and large foramen for the 1/6/09 9:25:36 AM 2008 Wible—On the Cranial Osteology of Solenodon paradoxus 375 Fig. 36.—Solenodon paradoxus, AMNH 185012, drawings of right mandible in lateral view. Abbreviations: an, angular process; c, lower canine; coc, coronoid crest; con, condylar process; cor, coronoid process; i1, lower first incisor; i2, lower second incisor; i3, lower third incisor; m1, lower first molar; m2, lower second molar; m3, lower third molar; maf, masseteric fossa; mb, mandibular body; mf, mental foramina; mr, mandibular ramus; p1, lower first premolar; p4, lower penultimate premolar; p5, lower ultimate premolar; pdm, process for digastric muscle; rms, retromolar space. occipital emissary vein (“oev” in Fig. 21C), presumably a difference of developmental stage. The sulcus arises at a right angle from the posterodorsal margin of the sulcus for the sigmoid sinus and is 4.0 mm long and 1.5 mm wide. It ends dorsolaterally at an opening that ultimately leads to the various supraoccipital foramina on the occiput (Figs. 34, 35). A part of the supraoccipital’s suture with the parietal is preserved at the anteroventral end of the sulcus for the occipital emissary vein showing the origin to be on the supraoccipital (Fig. 21C). In light of the position of the supraoccipital and parietal in the juvenile AMNH 28272, it seems likely that the bulk of the sulcus and foramen is on the supraoccipital in AMNH 28271. Ventral to the large foramen for the occipital emissary vein is a much smaller one in AMNH 28271 that is interpreted to be part of the same venous system. Mandible (Figs. 36–42) The paired mandible consists of the shallow, tooth-bearing horizontal part (body) and behind that, the broad vertical part (ramus). Each mandible houses ten teeth: three Wible.indd 375 incisors, canine, three premolars, and three molars. In AMNH 28271, 28272, and 185012, the right and left mandibles are separated from each other, whereas in CM 18069 and AMNH 212912 they are held together by soft tissues at the mandibular symphysis (Fig. 41). Allen (1908) described the teeth of the juvenile AMNH 28272, although several typographic errors complicate identifications at certain loci; McDowell (1958) redescribed the teeth and made corrections to Allen (1908). The identification of deciduous and permanent lower teeth followed here is in accord with McDowell (1958); the only loci explicitly known by two generations are the second incisor, and the penultimate and ultimate premolars. In lateral view, the body of the mandible (“mb” in Fig. 36) is fairly uniform in depth posterior to i3, with the deepest point below m3 and shallowest below m1. The body tapers anteriorly and is very shallow below the tiny i1, whose alveolus is anteroventral to the large i2. The m3 is separated from the coronoid process on the mandibular ramus by a narrow retromolar space (“rms” in Fig. 36). In the juveniles AMNH 28272 and 185012, the body is riddled with many tiny foramina, especially below the canine and premolars (Fig. 42), but the adults have far fewer such tiny 1/6/09 9:25:37 AM 376 Annals of Carnegie Museum Vol. 77 Fig. 37.—Solenodon paradoxus, AMNH 185012, drawings of right mandible in medial view. Abbreviations: an, angular process; ars, articular surface; c, lower canine; con, condylar process; cor, coronoid process; i2, lower second incisor; m1, lower first molar; manf, mandibular foramen; mas, mandibular symphysis; mb, mandibular body; mhl, mylohyoid line; mr, mandibular ramus; p4, lower penultimate premolar; pdm, process for digastric muscle. Fig. 38.—Solenodon paradoxus, AMNH 185012, drawings of right mandible in occlusal view. Abbreviations: an, angular process; ars, articular surface; c lower canine; con, condylar process; cor, coronoid process; i2, lower second incisor; m1, lower first molar; mas, mandibular symphysis; p4, lower penultimate premolar; pdm, process for digastric muscle; rms, retromolar space. Wible.indd 376 1/6/09 9:25:38 AM 2008 Wible—On the Cranial Osteology of Solenodon paradoxus foramina (Fig. 39). The five specimens have multiple mental foramina (four or more) in slightly different positions (“mf” in Fig. 36). In AMNH 28272 (Fig. 42), there are four large mental foramina (below the canine, the posterior root of p1, p4, and the anterior root of m1) on the left side and four (below the posterior root of p1, the anterior root of dp5, the anterior root of m1, and the posterior root of m1) on the right side (Fig. 39); there are extra small foramina on the right side (below the canine, the middle of p1, and the posterior root of m1). In AMNH 185012, there are four large mental foramina on the left side (below the posterior root of p1, the anterior root of p4, the anterior root of p5, and the p5/m1 embrasure) and two large (p1/p4 embrasure and posterior root of p4) and three small (canine, anterior root of m1, and anterior root of m2) on the right side (Fig. 36). In CM 18069, there are four large (c/p1 embrasure, p4 anterior root, anterior root of p5, and anterior root of m1) and a small one (middle of p4) on the right side (Fig. 39), and three large (c/p1 embrasure, p4 anterior root, and posterior root of p5) and two small (middle of p4 and posterior root of m1) on the left side. In AMNH 212912, there are four large (c/p1 embrasure, anterior root of p4, posterior root of p4, and anterior root of m1) on the right side (Fig. 39) and three large (posterior root of p1, posterior root of p4, and anterior root of m1) and one small (anterior root of p5) on the left. In AMNH 28271, there are three large mental foramina (below the middle of p1 and p4, and the anterior root of m1) and two small (below the canine and anterior root of p5) on the right side (Fig. 39), and three large (below the middle of p1, the posterior root of p5, and the anterior root of m1) and two small (below the canine and anterior root of m2) on the left. In AMNH 28272, 185012, and 212912, the mental foramina are positioned in roughly the same horizontal plane, but in AMNH 28271 and CM 18069 the anterior ones are higher than the posterior ones (Fig. 39). In medial view, the most prominent feature on the body is the cigar-shaped symphyseal surface, which extends posteriorly to beneath the anterior root of p5 in all specimens (“mas” in Fig. 37). The posterior part of the symphyseal surface is not flush with the surface of the body but is elevated. With the two mandibles in articulation, this elevated area produces a narrow shelf opposite p4 and p5 (Fig. 41). Ventral and posteroventral to m3 is a distinct crest, the mylohyoid line (more rounded in the adults), which continues posteriorly a short distance onto the mandibular ramus (“mhl” in Fig. 37). In lateral view, the dorsal aspect of the mandibular ramus (“mr” in Fig. 36) has the usual coronoid and condylar processes, positioned anteriorly and posteriorly respectively (“cor” and “con” in Fig. 36), but the ventral aspect appears to have two angular processes (“pdm” and “an” in Fig. 36). The anteroventral one lies beneath the coronoid process and is separated by a concavity from the posterodorsal one, which lies beneath the condylar process. The anteroventral process is smaller than the posterodorsal one, ends in a sharp point, and is slightly inflected medially. The Wible.indd 377 377 Fig. 39.—Solenodon paradoxus, AMNH 185012, CM 18069, AMNH 28271, and AMNH 212912, photographs of right mandibles in lateral view. Scale = 10 mm. posterodorsal process is more extensive, positioned at the posteroventral corner and extending up the posterior border of the ramus, rounded, and with a low, raised crest on its outer contour in the adults. The author agrees with Allen (1910), who considered the posterodorsal process to be the true angle, because in his dissections the masseter and medial pterygoid muscles attach there, whereas the digastric muscle attaches to the unnamed anteroventral process. The concavity separating the posterodorsal and anteroventral processes varies with the developmental stage, being more pronounced in the juveniles (Figs. 39, 42). The coronoid process is twice as high as the condylar process measured from the retromolar space and the base 1/6/09 9:25:39 AM 378 Annals of Carnegie Museum Vol. 77 Fig. 40.—Solenodon paradoxus, AMNH 185012 and AMNH 28271, photographs of right mandibles in medial view. Scale = 10 mm. of the coronoid lies at roughly a right angle to the occlusal plane. The anterior and dorsal borders of the coronoid process have a thickened coronoid crest (“coc” in Fig. 36), especially in the adults (Fig. 39). At the base of the coronoid process, the coronoid crest subtly turns posteriorly and then posterodorsally toward the concavity between the coronoid and condyle, demarcating the ventral and posterior limit of the masseteric fossa (“maf” in Fig. 36). Immediately above this subtle ridge is the deepest part of the masseteric fossa, a circular depression in the juveniles AMNH 28272 and 185012 and an oval depression (longer than high) in the adults (Fig. 39). Other than this depression, the surface of the ramus is fairly flat. Little of the condylar process is visible in lateral view. It is positioned roughly a molar length above the occlusal plane and is not delimited from the ramus by a penduncle or constricted neck in this view. In the juveniles AMNH 28272 and 185012, the most prominent feature on the ramus in medial view is a straight, rounded prominence that extends from the mylohyoid line on the body to the condyle dividing the ramus into dorsal and ventral parts (Figs. 37, 42). This prominence is not horizontal but angled posterodorsally. Slightly posterior to the midpoint of this prominence in its ventral aspect is the opening into the mandibular canal, the mandibular foramen (“manf” in Fig. 37). The surface dorsal to this prominence on the medial aspect of the coronoid process is for the temporalis muscle (Allen 1910). The adults differ from the juveniles in that there is a stout, posteroventrally directed extension arising from this prominence anterior to the mandibular foramen (Fig. 40); AMNH 185012 has the ventral two-thirds of this extension in a weak form (Figs. 37, 40). It extends to the outer contour of the angle and divides the medial aspect of the angle into subequal anteroventral and posterodorsal surfaces, the latter more deeply Wible.indd 378 excavated than the former. Allen (1910:16) described the medial pterygoid (his pterygoideus internus) as “inserting on the angle of the ramus” and the lateral pterygoid (his pterygoideus externus) as inserting “on the lower jaw inside the neck of the mandibular condyle forward to the inferior dental foramen” (mandibular foramen). It is not entirely clear how Allen’s descriptions relate to the morphology: either the lateral pterygoid occupies the entire posterodorsal surface or it occupies some smaller subset thereof with the medial pterygoid in the remainder. The condylar process is most readily seen in occlusal and posterior views (Figs. 38, 41). From above it is roughly triangular. The straight lateral side is the lateral surface of the ramus; the convex posterior side holds the articular surface (“ars” in Fig. 38); and the anteromedial side is slightly concave. The posterior and anteromedial sides meet at a sharp, medially directed point. McDowell (1958) described the articular surface in detail, noting the presence of two ovoid facets, corresponding to external and entoglenoid [his postglenoid] facets on the squamosal. The external facet is perpendicular to the plane of the ramus and faces dorsally and slightly posteriorly. The entoglenoid facet is only visible in posterior view because it lies on the posterior surface of the medially directed point mentioned above and is directed posteriorly and ventrally (“ars” in Fig. 37). The posteromedial aspect of the external facet abuts the dorsolateral aspect of the entoglenoid facet. The facets are present, but subtle in the juveniles AMNH 28272 and 185012, and in the adults are subequal Fig. 41.—Solenodon paradoxus, CM 18069 and AMNH 212912, photographs of right and left mandibles in occlusal view. Scale = 10 mm. 1/6/09 9:25:40 AM 2008 Wible—On the Cranial Osteology of Solenodon paradoxus 379 Fig. 42.—Solenodon paradoxus, AMNH 28272, photographs of left mandible in lateral (top) and medial (bottom) views. Third molar has fallen out and is missing; it is figured in Allen (1908: pl. XXXIII, fig. 5). Scale = 10 mm. Abbreviations: c, lower canine; di2, lower deciduous second incisor; dp5, lower deciduous third premolar; i1, lower first incisor; i2, crypt containing lower second incisor; i3, lower third incisor; m1, lower first molar; m2, lower second molar; p1, lower first premolar; p4, lower penultimate premolar; p5, lower ultimate premolar. in AMNH 28271 and CM 18069, but with the entoglenoid facet much smaller than the external in AMNH 212912. Hyoid Apparatus and Larynx A broken piece of stylohyal (stylohyoid of NAV 1994) is preserved in situ on the left side of AMNH 185012 and 212912 (“sh” in Figs. 25, 29), with the piece in the former more substantial that the latter. In both, the posterolateral end of the stylohyal articulates with the tympanohyal, and medial to that the stylohyal abuts the posterior crus of the ectotympanic and the caudal tympanic process of the petrosal (Fig. 29B). In ventral view (Fig. 25), the broken stylohyal is L-shaped with the union of the legs representing a small angle of the stylohyal. J.A. Allen (1908: fig. 9) and G.M Allen (1910: pl. 7, fig. 3) illustrated the hyoid bones and ossified larynx for S. paradoxus, but only the latter included description of these elements. From proximal to the skull base to distal, Wible.indd 379 the hyoid apparatus includes the paired stylohyals, epihyals, ceratohyals, and the median basihyal, which is fused to the paired thyrohyals. For completeness sake, the latter Allen’s figure is reproduced here (Fig. 43) and his descriptions (Allen 1910: 42–43) follow below. “It remains to describe briefly the laryngeal and hyoid bones. These appear to be similar to those of S. cubanus as figured by Peters (1864: pl. 2, fig. 11), and are well ossified. The thyroid is the largest, 13 mm in greatest length. It is slightly more than half a complete ring and has at the anterior dorsal margin on each side a process for the articulation with the tips of the thyrohyals [thyrohyoids of NAV 1994]. Posteriorly, the dorsal margin is similarly produced to form processes articulating with the posterolateral margin of the cricoid. A low ridge arises about midway of the straight dorsal border and curves ventrally to the posterior edge. Above it on each side is a minute foramen [Foramen thyroideum of NAV 1994] at the dorsal edge of the bone. On the left side in our specimen there is in addition a minute foramen about 2 mm anterior to the first. The 1/6/09 9:25:41 AM 380 Annals of Carnegie Museum Vol. 77 CONCLUSIONS Fig. 43.—Solenodon paradoxus, line drawing of hyoid apparatus and ossified larynx in oblique left lateral view such that some paired elements are visible bilaterally (redrawn and relabeled from Allen 1910: pl. 7, fig. 3). Median basihyal is fused to paired thyrohyals. Abbreviations: ashy, angle of stylohyal; bhy, basihyal; chy, ceratohyal; crc, cricoid; ehy, epihyal; f, foramen; sh, stylohyal; thd, thyroid; thfc, tympanohyal facet on stylohyal; thy, thyrohyal; thyrohyal of each side has fused ventrally with the basihyal [basihyoid of NAV 1994] so that the three bones thus form a half ring, bowed back at first, then forward at the ventral side. The ceratohyals [ceratohyoids of NAV 1994] are appressed against the ventrolateral margin of the ring. They are rather thick and about 4 mm in dorsoventral length. Their dorsal border, and the edge of the thyrohyal adjacent, articulate on each side with the epihyal [epihyoid of NAV 1994], a broad but laterally flattened bone, that projects anteriorly from this articulation. This in turn joins with the stylohyal, which is about 2 mm longer, and much more rounded and slender. It joins the skull by a very short bony process that projects at nearly right angles from its proximal end. This process may be fused to the tympanohyal [tympanohyoid of NAV 1994]. The cricoid at its anterior end is clasped by the converging posterior processes of the thyroid and is a complete bony ring, with a postero-dorsal extension. The vocal cords are attached by cartilage, one at each side from the anterior apex of this ring to its mid-ventral line, and pass forward as a delicate strand to a median attachment just back of the anterior edge of the thyroid. The first tracheal ring is the broadest and fits into the posterior end of the cricoid, to which it is bound by muscle fibers. Peters states that in S. cubanus the first nine tracheal rings are complete and that there are 21 in all. In S. paradoxus the number is slightly more, 22 to 29, and all are incomplete dorsally.” Wible.indd 380 The final arbiter of the significance of the detailed anatomy presented above is phylogenetic analysis, which is well beyond the scope of this report. In the literature, a term frequently encountered in conjunction with the morphology of the solenodon is “archaic.” For example, according to Eisenberg (1981:114), solenodons “possess very archaic morphological characters in conjunction with some apomorphic characters”, although he did not specify any of either type. Possibly accounting for the purported archaic (plesiomorphic) nature of the solenodon, molecular estimates place its divergence from other placentals at 76 million years ago (Roca et al. 2004). Does the solenodon skull possess plesiomorphic characters lost in more derived placentals? Gregory’s (1910:253) monograph on the orders of mammals provides the most detailed discussion of this subject, albeit in a pre-cladistic paradigm. In his “phyletic interpretation of the osteological characters of Solenodon paradoxus,” he noted “primitive placental [eutherian] characters,” “points of special resemblance to marsupials [metatherians],” and “primitive marsupio-placental [metatherian-eutherian] characters” for the solenodon. Skulls of Cretaceous therians were unknown in 1910, and significant advances have occurred in that front in recent years (Kielan-Jaworowska et al. 2004; Wible et al. 2005b). Current status of the features named by Gregory is reviewed among basal eutherians and metatherians in order to assess the supposed archaic nature of the solenodon. The primitive eutherian characters highlighted by Gregory (1910) included: “Orbitosphenoid pierced by optic foramen and not depressed dorsoventrally in such a way that the opposite sphenorbital fissures are confluent beneath it (contrast Marsupials); alisphenoid relatively small and not entering the glenoid fossa.” Both of these characters are widely distributed among placentals and do not distinguish the solenodon as plesiomorphic. An optic foramen with an orbitosphenoid not depressed dorsoventrally occurs in the few Cretaceous eutherians for which the orbitosphenoid is well preserved (Wible et al. 2005b) and also in nearly all extant placentals. In contrast, metatherians and the Early Cretaceous prototribosphenidan Vincelestes Bonaparte, 1986, lack the optic foramen and have confluent sphenorbital fissures (Rougier 1993; Rougier et al. 1998); the only exception is the Late Cretaceous metatherian Deltatheridium Gregory and Simpson, 1926, which has an optic foramen (Wible et al. 2005b), although the presence of a dorsoventrally depressed orbitosphenoid is unknown. Absence of a glenoid process of the alisphenoid is primitive for eutherians, but is even more widely distributed, being also absent in Vincelestes and Deltatheridium; the addition of this process is a feature occurring within Metatheria (Rougier et al. 1998). The second category highlighted by Gregory (1910), special resemblances (convergences) to metatherians, included: “Vomer with larger lateral posterior wings, joining 1/6/09 9:25:42 AM 2008 Wible—On the Cranial Osteology of Solenodon paradoxus ethmoid scroll. Large venous condylar foramina [condyloid canal]. A remnant of the tympanic wing [tympanic process] of the alisphenoid. Posterior mental foramen beneath m1.” (1) The status of the vomer is known in so few taxa that commentary is meaningless at this time. (2) The solenodon does share a large venous condyloid canal with marsupials, but it is not unique among placentals in that regard (e.g., dog, Evans 1993; ox, Sisson 1910). Moreover, a condyloid canal is absent in basal metatherians, such as Pucadelphys Marshall and Muizon, 1988 (Marshall et al. 1995) and Mayulestes Muizon, 1994 (Muizon 1998), as well as in basal eutherians, such as Zalambdalestes (Wible et al. 2004) and Maelestes (Wible et al. in press). (3) The solenodon does have a small tympanic process of the alisphenoid, which is widely distributed among marsupials (Horovitz and Sánchez-Villagra 2003), but it is not unique among placentals in that regard (e.g., Erinaceus europaeus Linnaeus, 1758, Potamogale velox (du Chaillu, 1860); Wible et al. 2007, in press). Moreover, a tympanic process is absent in basal metatherians, such as Pucadelphys (Marshall et al. 1995) and Mayulestes (Muizon 1998), and its addition is a synapomorphy of Marsupialia (Horovitz and Sánchez-Villagra 2003). (4) The solenodon does share a posteriormost mental foramen beneath the lower first molar with metatherians (Rougier et al. 1998; Wible et al. 2007, in press), but this occurs in other eutherians (e.g., Late Cretaceous Maelestes, Blarina brevicauda (Say, 1823), Potamogale velox; Wible et al. 2007, in press). The third category highlighted by Gregory (1910), primitive therian characters, was the longest by far and included: “Interparietal paired; orbitosphenoid invaded anteriorly by ethmoid chamber; pituitary depression slight, without posterior clinoid process; basioccipital very short. Alisphenoids with prominent palatine flanges [entopterygoid processes]. Posterior border of palate ridged [postpalatine torus]. General arrangement of ethmoids and maxillo-turbinals. Tympanic ring-shaped, oblique rather than vertical. Arrangement of following nerve foramina: olfactory, internal auditory [acoustic] meatus, facial canal, fenestra ovalis [vestibuli], foramen lacerum anterius [sphenorbital fissure] and posterius [jugular foramen], sphenopalatine, post-palatine [minor palatine] stylomastoid, and condylar [hypoglossal] foramina (the last occasionally double). Venous foramina: transverse canal [foramen] in basisphenoid (cf. Didelphis), ?sinus canal in temporal region [anterior opening, orbitotemporal canal], post-parietal [foramen for ramus temporalis], post-squamosal [foramen for ramus temporalis], post-glenoid [postglenoid], postmastoid [mastoid] foramina.” Commentary on several features in this category is not appropriate in light of our poor state of knowledge (i.e., orbitosphenoid invaded anteriorly by ethmoid chamber; general arrangement of ethmoids and maxillo-turbinals; olfactory foramina). The remainder can be divided into features for which subsequent research has shown Gregory’s polarity to be incorrect, uncertain, or correct. Five features thought by Gregory to be primitive for Wible.indd 381 381 Theria are no longer so considered. (1) Rather than primitively paired in therians, the interparietal is wholly absent in Cretaceous eutherians and basal metatherians (Rougier et al. 1998; Wible et al. 2007, in press). Additionally, when an interparietal occurs in placentals, it is usually a single ossification and not paired (Novacek 1993); the paired interparietal of the solenodon is not unique (De Beer 1937), but it is unusual. (2) The oval fenestra vestibuli of the solenodon does not resemble the rounder version of this aperture that occurs in basal metatherians and most basal eutherians and is clearly the primitive condition for Theria (Rougier et al. 1998; Wible et al. 2007, in press). (3) The solenodon sphenopalatine foramen with a contribution from the ethmoid to its bony border does not resemble the condition in basal eutherians and metatherians in which the opening is either within the palatine or between the palatine and maxilla (Wible et al. 2007, in press). (4) The solenodon stylomastoid notch with a contribution from the lateral section of the caudal tympanic process of the petrosal does not resemble the more open notch between only the tympanohyal and posterior continuation of the crista parotica of basal eutherians and metatherians (Rougier et al. 1998; Wible et al. 2001, 2007, in press). (5) The transverse canal foramen in the basisphenoid is absent in Cretaceous eutherians (Wible et al. 2007, in press) and is a synapomorphy within Metatheria (Horovitz and Sánchez-Villagra 2003). The presence of a transverse canal in the solenodon is not unique among placentals (e.g., Euphractus sexcinctus (Linnaeus, 1758), Wible and Gaudin 2004), but is unusual. The shape and orientation of one element, the ectotympanic, is of uncertain polarity for Theria, because this element is poorly known in basal eutherians and metatherians. Some forms (e.g., Maelestes) have a ring-shaped ectotympanic resembling that in the solenodon, whereas others (e.g., Zalambdalestes) have a slightly expanded, fusiform ectotympanic (Wible et al. 2007, in press). Even less is known about the inclination of the ectotympanic in basal therians than its form. Gregory inferred the correct polarity for Theria for the remaining features in the third category. However, there is little here that distinguishes the solenodon as plesiomorphic when compared to other placentals. In fact, for five features, the solenodon has some additional condition that sets it apart from most placentals and/or basal eutherians. (1) Little is known of the pituitary depression (hypophyseal fossa) in basal therians. Late Cretaceous Maelestes and Ukhaatherium Novacek et al., 1997, have a shallow fossa with a low dorsum sellae (Rougier et al. 1998; Wible et al. 2007, in press) resembling that in the solenodon. Yet, in both fossils and in placentals in general, the hypophyseal fossa is within the basisphenoid. The solenodon is unusual (perhaps even unique) in having a significant portion of the hypophyseal fossa formed within the basioccipital. (2) The solenodon has prominent entopterygoid processes as in basal therians (Wible et al. 2005b, 2007, in press). However, it lacks the ectopterygoid processes that distinguish the alisphenoids of basal eutherians and many placentals 1/6/09 9:25:42 AM 382 Annals of Carnegie Museum Vol. 77 from those of metatherians (Wible et al. 2005b, 2007, in press). (3) The solenodon minor palatine foramen with its narrow bony bridge forming the posterior border resembles the foramen that occurs widely in basal therians (Rougier et al. 1998; Wible et al. 2007, in press). However, the solenodon aperture is variably subdivided into two ventral apertures. (4) As in the solenodon, two or more hypoglossal foramina are present in Vincelestes (Rougier 1993), basal metatherians and most basal eutherians (Wible et al. 2007, in press). However, the solenodon is distinguished by having additional small foramina adjacent to the hypoglossal foramina that connect to the condyloid canal. (5) The stapedial artery system of the solenodon includes a well-developed anterior division of the ramus superior that enters the orbit via the anterior opening of the orbitotemporal canal, as in basal eutherians, such as asioryctitheres and zalambdalestids (Wible et al. 2004, 2007, in press). However, the solenodon is distinguished by the close association of the anterior opening of the orbitotemporal canal with the posterodorsal ethmoidal foramen and the frontal diploic vein foramina, which is unknown in other eutherians. A recent phylogenetic analysis of morphological characters that includes the solenodon along with Cretaceous eutherians by the author and colleagues (Wible et al. 2007, in press) does not identify the solenodon as an archaic form but nested well within Placentalia. Despite the general conception of some, such as Eisenberg (1981), regarding the archaic nature of the solenodon, its cranial osteology presents few plesiomorphic features lost in more derived placentals. The most striking of these, which is also previously unreported for the solenodon, is the presence of a prootic canal for the lateral head vein. A prootic canal is widely distributed among Mesozoic mammals, but only among a few Cretaceous eutherians (Wible et al. 2001, 2007, in press; Ekdale et al. 2004) and no other placentals. The unexpected discovery of this structure in the solenodon should alert others to be on the lookout for a prootic canal in other placentals. The overall form of the solenodon skull may appear to be archaic with its elongated snout, small eyes, and tubular braincase. However, rather than archaic, the cranial osteology described above paints a picture of an animal with a highly specialized head with numerous unique adaptations. From the os proboscidis in front, to the numerous venous foramina in the orbit (frontal diploic vein, supraoptic, and suboptic foramina), to the mallear articulation on the petrosal in the ear region, to the numerous venous foramina on the occiput, to the extra “angular” process on the lower jaw, the solenodon is one peculiar beast. ACKNOWLEDGMENTS As a graduate student years ago, three outstanding monographs incorporating observations on the skull of the solenodon had a tremendous influence on me: Gregory (1910), McDowell (1958), and MacPhee (1981). In the course of this project, I discovered several more amazing works on Wible.indd 382 this unusual animal, in particular Brandt (1833), Peters (1864), and Allen (1910). My first acknowledgment is to these researchers who motivated me in this project. However, my greatest debt in this project is to Paul Bowden, whose outstanding illustrations inspired me to get the anatomy correct; Paul meticulously completed all the artwork, while I am responsible for the photographs. I am also extremely grateful to the curators in the Department of Mammalogy of the American Museum of Natural History: Ross MacPhee, Nancy Simmons, and Rob Voss. Without their willingness to loan me the crucial skulls from their collection, this project would not have been possible. For various favors aiding the completion of this project, I thank Pat Brunauer and Teresa Pacheco at the American Museum of Natural History; Sue McLaren, Tim McCarthy, and Xianghua Sun at the Carnegie Museum of Natural History; and Tim Smith at Slippery Rock University. Thorough, insightful reviews by Guillermo Rougier and Norberto Giannini greatly improved the final product and helped me avoid some embarrassments. This work was supported by Carnegie Museum of Natural History and National Science Foundation ATOL grant 0629959. Literature Cited Allen, G.M. 1910. Solenodon paradoxus. Memoirs of the Museum of Comparative Zoology at Harvard College, 40:1–54, pl. 1–9. ———. 1918. Fossil mammals from Cuba. Bulletin of the Museum of Comparative Zoology, 62:133–148. Allen, J.A. 1908. Notes on Solenodon paradoxus Brandt. Bulletin of the American Museum of Natural History, 24(23):505–517. Archibald, J.D., and A.O. Averianov. 2003. The Late Cretaceous placental mammal Kulbeckia. 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Quarterly Review of Biology, 46:226–249. 1/6/09 9:25:43 AM 386 Annals of Carnegie Museum Vol. 77 Glossary In keeping with previous works by the author and collaborators (e.g., Wible 2003, 2007; Wible and Gaudin 2004; Giannini et al. 2006), below in alphabetical order is a treatment of 66 cranial structures (e.g., foramina, grooves, canals) associated with soft tissues (e.g., nerves, arteries, veins). The vast majority occurs in the solenodon, and the few that do not are included for the sake of completeness. As the point of reference, nearly every entry begins with the condition in the dog, because an excellent, well-illustrated textbook of canine anatomy exists (Evans 1993) and because the skull of the dog is more generalized than other well-documented taxa (e.g., humans, horses, rats). Two oft-cited monographs including observations on the skull and basicranium of the solenodon respectively are McDowell (1958) and MacPhee (1981). A common denominator of these works is a glossary of cranial and basicranial structures, which inspired the following. Accessory Palatine Foramen.—In the dog (Evans 1993), one or more accessory palatine foramina (following Wible and Rougier 2000) (=minor palatine foramina of Evans 1993) in the horizontal process of the palatine transmit accessory palatine nerves to the mucosa of the hard palate. These nerves arise from the major palatine nerve within the palatine canal (Evans 1993). In the solenodon, numerous openings occur in the palatomaxillary suture and the palatine bone on the back of the hard palate (Figs. 11–13). The exact contents are not known, but these openings are either major or accessory palatine foramina. Until additional study is done, those posterior to the anterior palatomaxillary suture are treated as accessory palatine foramina. Considerable variation occurs within and between specimens in the number and location of accessory palatine foramina. The right side of AMNH 28271 has the fewest with two entirely within palatine, and the left side of AMNH 212912 and right side of AMNH 185012 the most with four in the palatine and one in the palatomaxillary suture. Based on the bisected skull AMNH 28271, the accessory palatine nerves have a separate small foramen of exit from the nasopharyngeal meatus opposite the upper ultimate molar (“apf” in Fig. 22). Alisphenoid Canal.—In the dog (Evans 1993), the alisphenoid canal (following Gregory 1910) (=alar canal of Evans 1993) runs through the base of the alisphenoid (=temporal wing of the sphenoid of Evans 1993); its smaller caudal opening transmits the maxillary artery and vein and its larger rostral opening the maxillary artery, vein, and nerve. The maxillary nerve enters the canal via the foramen rotundum in the canal’s roof. In the solenodon, the alisphenoid canal lies anterior to the foramen ovale and transverse canal foramen within the alisphenoid (“asc” in Figs. 14–16) and is merely a foramen of entry into the skull (=caudal alar foramen of the dog) rather than a canal. Gregory (1910:246) suggested that the solenodon alisphenoid canal transmitted a branch of the external carotid artery Wible.indd 386 (=ectocarotid artery of Gregory 1910); McDowell (1958), citing Gregory (1920a), identified the ramus inferior of the stapedial artery as the primary occupant. MPIH 6863 does not preserve sections rostral to the foramen ovale, but the major artery below that opening is the ramus infraorbitalis, a primary branch of the ramus inferior of the stapedial artery (Wible 1987; Fig. 26C). Consequently, it seems more likely that the ramus infraorbitalis is the primary occupant of the alisphenoid canal. Alveolar Foramina.—In the dog (Evans 1993:150), “leading from the infraorbital canal to the individual roots of the premolar teeth (first four cheek teeth) are the alveolar canals (canales alveolares), which open by numerous alveolar foramina (foramina alveolaria) in the apex of each alveolus. The special incisivomaxillary canal (canalis maxilloincisivus) carries the nerves and blood vessels to the first three premolar and the canine and incisor teeth. It leaves the medial wall of the infraorbital foramen, passes dorsal to the apex of the canine alveolus with which it communicates, and enters the incisive bone [=premaxilla].” In the solenodon, the usual pattern is two primary alveolar foramina: a larger anterior one dorsomedial to the anterolabial root of the upper ultimate premolar, anterior to the infraorbital foramen (“imc” in Fig. 6) and a smaller posterior one within the infraorbital canal (“af” in Fig. 10). In AMNH 185012, the former foramen can be traced through the thin bone nearly to the premaxilla (Fig. 7) and, therefore, must be equivalent to the incisivomaxillary canal of the dog. Carotid Foramen and Sulcus.—In the dog (Evans 1993), the internal carotid artery crosses the basicranium within a perbullar canal (sensu Wible 1986) through the medial wall of the auditory bulla. Three foramina are associated with this course: one at the caudal entrance into the carotid canal, a second at the rostral exit from the carotid canal, and a third at the entrance into the cranial cavity between the petrosal (=pars petrosa of the temporal bone of Evans 1993) and basisphenoid (for discussion of the terminology of these foramina see Wible and Gaudin 2004:149). Within the cranial cavity, the artery runs in a shallow, anteromedially directed carotid sulcus in the basisphenoid, posterolateral to the hypophyseal fossa. In the solenodon, the internal carotid artery (=entocarotid artery of Gregory 1910; arteria promotorii of McDowell 1958) crosses the basicranium in a transpromontorial position (sensu Wible 1986) in a sulcus on the pars cochlearis of the petrosal (“gica” in Figs. 27A, 28; “ica” in Fig. 26C). It enters the cranial cavity either via the medial aspect of the piriform fenestra in AMNH 28271, 28272 (Fig. 26C), 185012 (right side), and CM 18069 (left side) or a separate carotid foramen in the basisphenoid in the medial aspect of the piriform fenestra in AMNH 185012 (left side, “cf” in Fig. 25), 212912, and CM 18069 (right side). Within the cranial cavity is a faint, anteromedially directed carotid sulcus on the basisphenoid, anterolateral to the hypophyseal fossa (“gica” in Fig. 22). 1/6/09 9:25:43 AM 2008 Wible—On the Cranial Osteology of Solenodon paradoxus Cavum Epiptericum.—see Pterygoid Canal. Caudal Palatine Foramen.—In the dog (Evans 1993), the caudal palatine foramen for the major palatine nerve, artery, and vein is separate from the sphenopalatine foramen, with both foramina in the perpendicular process of the palatine. In the solenodon, a separate caudal palatine foramen is lacking, and its contents pass through the sphenopalatine foramen (“spf” in Figs. 10, 15). situated just rostral to the center of the basisphenoid interpreted as a craniopharyngeal canal (“cpc” in Figs. 25, 27A); in the adults this is reduced to a miniscule slit. A craniopharyngeal canal does not occur in the available sections of MPIH 6863, but only the posterior basisphenoid is represented. In AMNH 28272, Gregory (1910:245; “f.ch.d.” in Fig. 1) identified a small midline hole between the basi- and presphenoid as possibly lodging “a ventral apophysis of the vestigial chorda dorsalis [=notochord]”, but labeled in his figure is the open intersphenoidal synchondrosis. Cochlear Canaliculus.—In the dog (Evans 1993), the perilymphatic duct reaches the inner ear from the cranial cavity via the external opening of the cochlear canaliculus in the petrosal (=pars petrosa of the temporal bone of Evans 1993) in the rostral edge of the jugular foramen. The jugular foramen is deeply recessed and partially obscured by the auditory bulla, but the ventral edge of the aperture can be seen from the ventral side (e.g., CM 30471). In the solenodon, the external opening of the cochlear canaliculus (=aqueductus cochleae of McDowell 1958) is similarly situated in the rostral edge of the jugular foramen with its ventral edge visible from the ventral side (not visible in the figures). Cribroethmoidal Foramen.—In the dog (Evans 1993), the ethmoidal nerve passes through an unnamed opening in the cribriform plate to reach the nasal cavity. In humans (Terry 1942), the anterior ethmoidal nerve enters the nasal cavity via the ethmoidal fissure, a slit-like opening at the side of the crista galli; the posterior ethmoidal nerve does not enter the nasal cavity, but is distributed to the posterior ethmoidal air cells and sphenoidal sinus. In the solenodon (AMNH 28271), a large opening in the dorsomedial aspect of the cribriform plate (“cef” in Fig. 23) medial to foramina to the nasoturbinate is interpreted here as for the ethmoidal nerves. Following Moore (1981), this opening is the cribroethmoidal foramen. Condyloid Canal.—In the dog (Evans 1993:136), “the rather large condyloid canal...runs through the medial part of the lateral occipital bone [=exoccipital]. There is an intraosseous passage between the condyloid canal and the hypoglossal canal. Usually there is also a small passage between the condyloid canal and the petrobasilar fissure.” The condyloid canal transmits the condyloid vein, which connects the sigmoid sinus and the basilar sinus. In the solenodon, the large condyloid canal (=venous condylar foramen of Gregory 1910) differs in that its primary exit is not endocranial. In the bisected skull, AMNH 28271, the condyloid canal begins at several large openings at the terminus of the sigmoid sinus sulcus (“coca” in Fig. 21C) and ends at the dorsal and ventral condyloid foramina (lacking in the dog) and hypoglossal foramina (“vcf” and “hf” in Fig. 26B; “dcf” in Figs. 34, 35). In light of the size of the condyloid canal, it represents the primary exit for the sigmoid sinus; the contents of the canal are unknown for MPIH 6863 because of lack of preservation. Two specimens, AMNH 212912 and CM 18069, also have a small endocranial opening just internal to the foramen magnum resembling the large caudal opening of the condyloid canal in the dog. Dorsal Condyloid Foramen.—In the solenodon, the dorsal condyloid fossa dorsal to the occipital condyle on the exoccipital’s vertical process on the occiput has at least one well-developed foramen in its medial margin that connects to the condyloid canal (“dcf” in Figs. 34, 35). AMNH 28271, 28272 (left side), 185012 (left side), and CM 18069 (right side) have an additional small opening; and AMNH 28272 (right side) has two small openings. In the dog (Evans 1993), dorsal condyloid foramina are not reported or illustrated. Cavum Supracochleare.—see Facial Canal and/or Sulcus. Craniopharyngeal Canal.—In the dog (Evans 1993:139), in the basisphenoid “occasionally the small craniopharyngeal canal...persists in the adult, particularly in Bulldogs. This midline canal is a remnant of the pharyngeal diverticulum to the hypophyseal fossa from which the pars glandularis of the hypophysis develops.” The juvenile solenodons AMNH 28272 and 185012 have a visible midline foramen Wible.indd 387 387 Ethmoidal Foramen.—In the dog (Evans 1993), two ethmoidal foramina usually occur per side, a larger posterodorsal one in the orbital process of the frontal for the external ethmoidal artery and vein, and a smaller anteroventral one in the suture between the frontal and orbitosphenoid for the ethmoidal nerve. Endocranially, these foramina open posterolateral to the cribriform plate, with the anteroventral one between the orbitosphenoid (=orbital wing of the presphenoid of Evans 1993) and ethmoid; the disposition of the posterodorsal foramen is not reported by Evans (1993). In CM 25053, both ethmoidal foramina are entirely within the frontal both extracranially and endocranially. The solenodon also has two ethmoidal foramina, a smaller anteroventral one within the frontal and a larger posterodorsal one between the frontal and orbitosphenoid, based on AMNH 28272 (“aef” and “pef” in Figs. 16, 19). The latter foramen is within a common depression with the anterior opening of the orbitotemporal canal, except in AMNH 212912. Endocranially, both foramina open into a sulcus posterolateral to the cribriform plate of the ethmoid 1/6/09 9:25:43 AM 388 Annals of Carnegie Museum Vol. 77 (“aef” and “pef” in Fig. 22); the bony disposition of these foramina is uncertain. Facial Canal and/or Sulcus.—In the dog (Evans 1993), the course of the facial nerve through the middle ear is entirely within a bony canal within the petrosal (=pars petrosa of the temporal bone of Evans 1993) between the cavum supracochleare (following Voit 1909) (=genu of the facial canal of Evans 1993), the space housing the geniculate ganglion of the facial nerve, and the stylomastoid foramen. In the solenodon, based on MPIH 6863, the facial nerve occupies a sulcus on the pars canalicularis of the petrosal (“fs” in Figs. 25, 26B, 28) between its exit from the cavum supracochleare, the secondary facial foramen, and the stylomastoid notch. In the segment of the facial sulcus anterior to the fenestra vestibuli, the stapedial artery runs ventral to the facial nerve. In the short segment posterior to the fenestra vestibuli, the facial nerve runs medial to the lateral head vein and then leaves the middle ear at the stylomastoid notch passing ventrolateral to the vein. Foramen for Frontal Diploic Vein.—In the dog (Evans 1993), the frontal diploic vein, an emissary vein of the diploë of the frontal bone to the dorsal external ophthalmic vein, leaves the skull via a small unnamed foramen in the orbital surface of the postorbital process of the frontal (=zygomatic process of the frontal of Evans 1993). Rather than a small foramen near the supraorbital rim as in the dog, the solenodon has one or more, larger openings, within the frontal in AMNH 28272, more ventrally placed near the posterodorsal ethmoidal foramen and the anterior opening of the orbitotemporal canal and/or the anteroventral ethmoidal foramen (“fdv” in Figs. 14, 16, 19). Based on the bisected skull AMNH 28271, the frontal diploic vein runs between the inner and outer table of the frontal bone in the annular ridge, which demarcates the rostral and middle cranial fossae, and communicates across the dorsal midline (“fdv” in Fig. 21C). Gregory (1910) employed the term supra-ethmoid foramen for the frontal diploic vein foramen (Fig. 1). Foramen for Inferior Petrosal Sinus.—In the dog (Evans 1993), the inferior petrosal sinus (=ventral petrosal sinus of Evans 1993) connects the cavernous sinus with the internal jugular vein via the petrobasilar (petro-occipital) canal, between the petrosal (=pars petrosa of the temporal of Evans 1993) and the basioccipital (=basilar part of the occipital of Evans 1993). Accompanying the inferior petrosal sinus is a condyloid artery off the occipital artery. The foramen for inferior petrosal sinus (=posterior opening of the petro-occipital canal of Evans 1993) lies anterior to the jugular foramen. In the solenodon, based on MPIH 6863, the inferior petrosal sinus occupies a groove on the medial face of the pars cochlearis of the petrosal (“ips” in Fig. 25). Dorsal to the groove, the pars cochlearis overlaps the basioccipital, forming a roof over the groove. There is also a partial floor to the groove formed by a lamina on the pars Wible.indd 388 cochlearis that varies in length; it runs the length between the anterior pole and jugular foramen in AMNH 185012 (Fig. 25) but is confined to the rostral half of the pars cochlearis in CM 18069 and AMNH 28271 and 212912. The foramen for the inferior petrosal sinus occurs at the posterior end of the lamina on the pars cochlearis. Foramen for Ramus Superior.—In the solenodon (McDowell 1958), a separate foramen for the ramus superior of the stapedial artery is lacking and the artery enters the cranial cavity via the piriform fenestra (=pyriform fenestra of McDowell 1958) (“rs” in Fig. 26C), confirmed by MPIH 6863 (see also MacPhee 1981). The dog lacks the ramus superior of the stapedial artery and foramen. Foramen Magnum.—In the dog (Evans 1993), the foramen magnum is enclosed between the basi-, ex-, and supraoccipital (=basilar, lateral, and squamous parts of the occipital bone of Evans 1993), which are fused together in the adult. The solenodon has the same arrangement. The sectioned juvenile MPIH 6863 preserves the suture between the basi- and exoccipital and reveals that the basioccipital forms the odontoid notch and part of the adjacent occipital condyles on the anterior rim of the foramen magnum, and AMNH 28272 preserves the suture between the ex- and supraoccipital and reveals that the supraoccipital forms the dorsal rim of the foramen magnum (“fm” in Fig. 35). The remaining specimens have a single occipital bone rimming the foramen magnum. The foramen magnum is elliptical, wider than high (Figs. 34, 35). Foramen Ovale.—In the dog (Evans 1993), the foramen ovale is in the base of the alisphenoid (=temporal wing of the basisphenoid of Evans 1993) and transmits the mandibular nerve and a small emissary vein; a small notch or even a separate foramen spinosum for the middle meningeal artery may be present in the posterolateral border of the foramen ovale. In the solenodon, the foramen ovale is in the alisphenoid immediately anterior to a low alisphenoid tympanic process (“fo” in Figs. 25, 27A). In MPIH 6863, the mandibular nerve is the primary occupant, but also transmitted are small veins and a small meningeal artery off the ramus mandibularis (“mnb” in Fig. 26C); the ramus inferior of the stapedial artery divides into the ramus infraorbitalis and ramus mandibularis posteroventral to the foramen ovale (Fig. 26C). Foramen Rotundum.—In the dog (Evans 1993), the maxillary nerve and a small emissary vein exit the cranial cavity via a foramen rotundum in the base of alisphenoid (=the temporal wing of the basisphenoid of Evans 1993) and then exit the skull via the rostral opening of alisphenoid canal (=rostral alar foramen of Evans 1993). In the solenodon, a separate foramen rotundum for the maxillary nerve is lacking and, according to Gregory (1910) the nerve exits via the foramen lacerum anterius (=sphenorbital fissure) (“sof” in Figs. 14, 16). 1/6/09 9:25:43 AM 2008 Wible—On the Cranial Osteology of Solenodon paradoxus Foramen for Ramus Temporalis.—In the solenodon, the examined adult skulls have between three and six foramina in the lateral braincase wall identified following MacPhee (1994) as foramina for rami temporales (including the post-parietal and post-squamosal foramina of Gregory 1910) for arterial and venous blood to the overlying temporalis muscle (“rt” in Figs. 2, 5, 6). The more posterodorsal of these foramina have well-developed grooves extending posterodorsally and dorsally into the temporal fossa. Because the parietosquamous suture is fused in the adults (Fig. 7), the exact bony location of these foramina is uncertain. In the juveniles, which retain the parietosquamous suture, some foramina are in the parietosquamous suture, others within the squamosal near the parietosquamous suture, and lastly one constant foramen within the squamosal well away from the suture (Fig. 6). AMNH 28272 has two foramina in the suture per side and two near the suture on the left side only; AMNH 185012 has one in the left suture, three in the right suture, and one near the suture on both sides, with the one on the left minute. In contrast, the dog has no foramina for rami temporales and the blood supply to the temporalis muscle derives from the external carotid system (Evans 1993). Glaserian Fissure.—According to Klaauw (1931:164), during ontogeny, the Glaserian fissure forms in the anterior wall of the presumptive auditory bulla as an aperture for Meckel’s cartilage, which subsequently disappears and “later on we find the chorda tympani nerve in it and often also the ramus inferior of the stapedial artery.” In the dog, the ramus inferior is lacking (Tandler 1899; Bugge 1978) and the chorda tympani nerve leaves the middle ear anteriorly “through a small canal in the rostrodorsal wall of the tympanic [=ecto- + entotympanic] bulla, and emerges through the petrotympanic fissure to join the lingual nerve (Evans 1993:978).” This small unnamed canal is the Glaserian fissure. In the solenodon, the chorda tympani and ramus inferior do not leave the middle ear together in MPIH 6863 as noted by MacPhee (1981), and it is the course of the former that marks the Glaserian fissure. Based on the specimens with the ectotympanic in place (AMNH 28271 [left side], 185012 [right side], 212912, CM 18069 [right side]), the chorda tympani nerve leaves the middle ear medial to the postglenoid foramen via a small opening between the rostral process of the malleus, anterior crus of the ectotympanic, and entoglenoid process of the squamosal. It then runs anteroventrally in a sulcus on the entoglenoid process (“gct” in Figs. 25, 26B), the groove for the chorda tympani of McDowell (1958). Groove for Chorda Tympani Nerve.—see Glaserian Fissure. Hiatus Fallopii.—In the dog (Evans 1993), the greater petrosal nerve (=major petrosal nerve of Evans 1993) runs forward from the geniculate ganglion of the facial nerve in the small petrosal canal in the petrosal (=pars petrosa of Wible.indd 389 389 the temporal bone of Evans 1993) dorsal to the fossa for the tensor tympani muscle. The hiatus Fallopii (=anterior opening of the petrosal canal of Evans 1993) is in the petrosquamous suture. In the solenodon, the hiatus Fallopii is also dorsal to the fossa for the tensor tympani muscle, but anterior to the hiatus is the broad piriform fenestra. The position of the opening in mammals has been characterized (e.g., Sánchez-Villagra and Wible 2002) based on the relationship between its floor and roof (dorsal with floor longer than roof, intermediate with roof and floor subequal, or ventral with roof longer than floor). All three conditions are exhibited in the solenodon specimens examined (for location see “hF” in Fig. 27A; nerve is reconstructed in Fig. 27B). Hypoglossal Foramen.—In the dog (Evans 1993), the hypoglossal foramen, the external opening of the hypoglossal canal, is in the exoccipital (=lateral part of the occipital of Evans 1993) posterolateral to the jugular foramen and transmits the hypoglossal nerve and vein. In the solenodon, two hypoglossal foramina (=condylar foramina of Gregory 1910) occur per side (“hf” in Figs. 25, 26B) except for the right side of AMNH 185012, which has three (all three are not visible in direct ventral view in Fig. 25). The exact contents of the hypoglossal foramina cannot be verified, because MPIH 6863 does not preserve them. The position and size of the foramina relative to each other varies among the examined skulls. In the adults, the foramina open into a common depression, but this only occurs on the right side of AMNH 185012 in the two juveniles (Fig. 25). All have small foramina adjacent to the hypoglossal foramina that connect to the condyloid canal. Incisive Foramen.—In the dog (Evans 1993), the beanshaped incisive foramen (=palatine fissure of Evans 1993) is in the premaxilla (=incisive bone of Evans 1993) with the maxilla forming the posterior border roughly medial to the upper canine. It is longer than the alveolus for any of the three upper incisors. The incisive foramen transmits the nasopalatine duct connecting the oral and nasal cavities with the vomeronasal organ, the rostral septal branch of the major palatine artery, and the nasopalatine nerve (=septal branch of the caudal nasal nerve of Evans 1993). In the solenodon, the oval incisive foramen (“inf” in Fig. 11) is almost completely in the premaxilla, with the maxilla forming the narrow posteriormost border, and is at the level of the diastema between the first and second incisors, with length approximating that of the upper third incisor alveolus, the smallest of the three upper incisors. Asher (2001) reports the nasopalatine duct connecting the nasal and oral cavities via the incisive foramen in a serially sectioned S. paradoxus identified as neo/postnatal in age and also that the vomeronasal duct opens directly into the nasal fossa and not into the nasopalatine duct as in the dog. Incisivomaxillary Canal.—see Alveolar Foramina. Infraorbital Canal.—In the dog (Evans 1993), the 1/6/09 9:25:43 AM 390 Annals of Carnegie Museum Vol. 77 infraorbital canal transmits the infraorbital nerve, artery, and vein from the orbit to the snout and is roughly the length of the enlarged upper carnassial tooth (P5), to which it is dorsal; in CM 30471, the P5 is 30% longer than the M1. In the solenodon, the infraorbital canal is relatively shorter, slightly less than the length of the upper first molar (M1), to which it is dorsal (Figs. 6, 7). Infraorbital Foramen.—In the dog (Evans 1993), the elliptical infraorbital foramen, the anterior opening of the infraorbital canal, is within the maxilla on the snout dorsal to the penultimate upper premolar (P4). In the solenodon, the oval infraorbital foramen is dorsal to the anterolingual root of the upper first molar (M1) (“iof” in Fig. 6). Internal Acoustic Meatus.—In the dog (Evans 1993:143), the internal acoustic meatus “is an irregularly elliptical depression that is divided deeply by the transverse crest (crista transversa). Dorsal to the crest is the opening of the facial canal, which contains the facial nerve as well as the cribriform dorsal [=superior] vestibular area (area vestibularis utriculo-ampullaris) for the passage of nerve bundles from the membranous labyrinth. Ventral to the crest is the ventral [=inferior] vestibular area (area vestibularis saccularis), through which pass additional vestibular nerve bundles that come from a deep, minute depression, the foramen singulare. The spiral cribriform tract (tractus spiralis foraminosus) is formed by the wall of the hollow modiolus of the cochlea. The perforations are formed by the fascicles of the cochlear nerve that arise from the spiral ganglion on the outside of the modiolus.” The solenodon AMNH 28271 (Figs. 20, 21A, C, 22) differs from the dog (e.g., CM 106574) in the overall depth of the transverse crest (“tc” in Fig. 22) and the foramen acusticum superius and inferius (the fossae on either side of the transverse crest); in the former these are only slightly recessed from the surrounding pars cochlearis and in the latter they are very deeply recessed. The other major difference concerns the number and size of the openings in the foramen acusticum inferius. In the dog (e.g., CM 106574) as in the newborn human (Terry 1942: fig. 137), the foramen centrale cochleare in the spiral cribriform tract, which is the orifice of the canal of the modiolus, is smaller than the inferior vestibular area, whereas in the solenodon it is four times larger. Additionally, in the dog (e.g., CM 106574), a foramen singulare separate from the inferior vestibular area is not visible, whereas in the solenodon these two entities are broadly separated (“fsi” and “iva” in Fig. 22). Jugular Foramen.—In the dog (Evans 1993), the jugular foramen is between the petrosal (=pars petrosa of the temporal bone of Evans 1993) and the occipital; based on the disarticulated skull of a puppy (Evans 1993: fig. 4–45), it appears to be largely or wholly the exoccipital (=lateral part of the occipital of Evans 1993) that borders the foramen. Transmitted are the glossopharyngeal, vagus, and accessory nerves and the sigmoid sinus, which then pass through the petro-occipital and tympano-occipital fissures Wible.indd 390 to reach the skull base. In the solenodon, the jugular foramen (=foramen lacerum posterius of Gregory 191; “jf” in Figs. 25, 26B, 28) is largely between the petrosal and exoccipital with only a minor contribution of the basioccipital to the anterior border based on MPIH 6863, the only specimen to delimit the basi- and exoccipital. Transmitted are the same nerves as in the dog (Gregory 1910); there is some venous drainage based on MPIH 6863, but the primary conduit for the sigmoid sinus is the condyloid canal. Lacrimal Fenestra.—In the dog (Evans 1993:1041), the inferior oblique muscle (=musculus obliquus ventralis of Evans 1993) “originates from a small depression in the palatine bone near the junction of the palatomaxillary and the palatolacrimal sutures. In prepared skulls this site may appear as a foramen, since the attachment plate is thin and easily lost.” Following Jollie (1968) and Gaudin and Wible (2004), this depression is a lacrimal fenestra. In the solenodon juveniles, the lacrimal fenestra is a slit in the suture between the orbital process of the lacrimal and maxilla (“lacfe” in Figs. 6, 8, 10); in the adults, the lacrimal fenestra is replaced by a pit via the closure of the suture between the lacrimal and maxilla. Lacrimal Foramen.—In the dog (Evans 1993), the large opening in the center of the orbital process of the lacrimal is called the fossa for the lacrimal sac. The lacrimal sac, formed by the union of the two lacrimal ducts, one from each eyelid, leads into the nasolacrimal canal, by which the nasolacrimal duct reaches the nasal vestibule. The solenodon has a similar arrangement with a large foramen in the lacrimal immediately posteromedial to the orbital rim that narrows into a canal anteriorly (“lacf” in Figs. 6, 8, 10). However, rather than calling this a fossa for the lacrimal sac, the general term lacrimal foramen (=lacrymal foramen of Gregory 1910) is employed. Major Palatine Foramen.—In the dog (Evans 1993), the major palatine nerve and vessels leave the pterygopalatine fossa via the caudal palatine foramen, run through the palatine canal in the palatine bone, and reach the hard palate via the major palatine foramen between the maxilla and palatine opposite the distal part of the upper ultimate premolar. In the solenodon, there are a number of foramina in the palatomaxillary suture and the palatine bone on the back of the hard palate (Figs. 11–13). The exact contents are not known, but these openings are either major or accessory palatine foramina. Until additional study is done, those in the anterior palatomaxillary suture in the vicinity of the M1/M2 embrasure are treated as major palatine foramina (“mapf” in Fig. 11). Variation occurs within and between specimens in the number and position of major palatine foramina. AMNH 185012 has one major palatine foramen per side in the anterolateral palatomaxillary suture; AMNH 28271 (right side) and CM 18069 (right side) have two in the suture, one anterolateral and the other anteromedial; AMNH 28271 (left side) and CM 18069 (left side) have one anteromedial in the suture; and AMNH 1/6/09 9:25:43 AM 2008 Wible—On the Cranial Osteology of Solenodon paradoxus 212912 has two per side, but the anteromedial one on the right is within the maxilla and the anterolateral one on the left is within the palatine. Based on the bisected solenodon skull AMNH 28271, the major palatine nerve leaves the pterygopalatine fossa via the sphenopalatine foramen, enters the nasopharyngeal meatus, and then exits the meatus via a foramen opposite the embrasure between the upper penultimate and ultimate molar (“mapf” in Fig. 21C). Mandibular Foramen.—In the dog (Evans 1993), the mandibular foramen, the caudal opening of the mandibular canal for the inferior alveolar nerve, artery, and vein (=mandibular alveolar nerve, artery, and vein of Evans 1993), is on the medial side of the mandibular ramus, approximately in the antero-posterior center, ventral to the alveolar margin. In the solenodon, the mandibular foramen is slightly posterior to the antero-posterior midpoint of the mandibular ramus, dorsal to the alveolar margin (“manf” in Fig. 37). Mastoid Canaliculus.—In the dog (Evans 1993), the auricular ramus of the vagus nerve in its course between the jugular foramen and stylomastoid foramen runs in a small canal in the petrosal (=pars petrosa of the temporal bone of Evans 1993), the mastoid canaliculus of NAV (1994). In the solenodon, the auricular ramus of the vagus is not enclosed in a bony canal but passes through the back of the middle ear, posterior to the fenestra cochleae, which it reaches by penetrating broad medial and lateral gaps (“abX” in Fig. 27B). The medial gap lies lateral to the jugular foramen between the medial section of the caudal tympanic process, the rostral tympanic process, and the pars canalicularis of the petrosal (“mc” in Figs. 25, 27A, 29A); the lateral gap lies medial to the stylomastoid foramen between the medial and lateral sections of the caudal tympanic process and the pars canalicularis of the petrosal. In addition to transmitting the auricular ramus, this passageway also transmits the lateral head vein (Fig. 27B). Mastoid Foramen.—In the dog (Evans 1993), the mastoid foramen is on the occiput between the mastoid exposure of the petrosal (=mastoid process of Evans 1993) and ex- and supraoccipital (=lateral and squamous parts of the occipital of Evans 1993); it transmits the occipital emissary vein, which joins the sigmoid sinus endocranially. Also reported by Evans (1993:608) is a caudal meningeal artery off the occipital artery that “goes through the supramastoid foramen and ramifies in the dura [mater] of the occipital cranial fossa”; the supramastoid foramen does not appear elsewhere in the text and may be the mastoid foramen. In the solenodon, McDowell (1958) reported the mastoid foramen (his postmastoid foramen) to be absent, but one or two small openings penetrate the mastoid exposure in all specimens (“msf” in Fig. 34) except the juvenile AMNH 28272 and the left side of AMNH 212912. On the left side of AMNH 185012 and right side of AMNH 28271 is a dorsomedially placed foramen, near the suture Wible.indd 391 391 with the parietal. On the right side of AMNH 185012 and 212912 and bilaterally in AMNH 28271 and CM 18069 is a more ventrolaterally placed foramen, near the suture with the squamosal. The latter openings bear a resemblance in position to posterior openings into the posttemporal canal. However, they do not lead into a canal between the pars canalicularis and squamosal and, therefore, are not posttemporal foramina. MacPhee (1994: fig. 6 [p. 65]) illustrated a mastoid foramen for S. cubanus near the dorsomedial corner of the mastoid exposure’s suture with the fused ex- and supraoccipital. Maxillary Foramen.—In the dog (e.g., CM 30471), the maxillary foramen, the posterior opening of the infraorbital canal, is in the anteroventral orbit dorsal to the posterior root of the upper ultimate premolar (P5) between the maxilla, palatine, and jugal. In the solenodon, the maxillary foramen is entirely within the maxilla dorsal to the embrasure between the upper first and second molars (M1 and M2) (“mxf” in Fig. 10). Mental Foramen.—In the dog (Evans 1993), two or more mental foramina in the mandibular body below the lower anterior premolars transmit the mental nerves, arteries, and veins from the mandibular canal. In the solenodon, the five examined skulls have four or more mental foramina (“mf” in Fig. 36) that vary in size and position both within and between specimens (Figs. 39, 42). The anterior and posterior extremes are below the lower canine and below the posterior root of the lower first molar (see Mandible for details). The mental foramina are positioned in roughly the same horizontal plane in AMNH 28272, 185012, and 212912, but the anterior ones are higher than the posterior ones in AMNH 28271 and CM 18069. Minor Palatine Foramen.—In the dog (Evans 1993), the minor palatine nerve and artery arise in the pterygopalatine fossa and run anteroventrally in a deep notch in the posterior edge of the palate between the palatine and maxilla that rarely is closed to form a foramen, the minor palatine foramen (following Wible and Rougier 2000). In the solenodon, McDowell (1958:146) noted the unusual nature of the minor palatine foramen (his posterior palatine canal): “it is bored vertically, and forked, with a single dorsal (orbital) opening, and two ventral (palatal) openings, one anterior and one posterior to the postpalatine torus.” The examined skulls show variability (see Fig. 13). The right side of AMNH 212912 has the three openings reported by McDowell (1958): one in the anteroventral pterygopalatine fossa, the dorsal minor palatine foramen; the second leading anteriorly onto the hard palate, the anteroventral minor palatine foramen; and the third leading posteriorly onto the soft palate, the posteroventral minor palatine foramen. AMNH 185012 and 212912 (left side) have only two foramina, because the anteroventral minor palatine foramen is a notch open ventrally, and CM 18069 has only one foramen, because the dorsal and posteroventral minor 1/6/09 9:25:43 AM 392 Annals of Carnegie Museum Vol. 77 palatine foramina are notches open posteriorly. McDowell (1958) reported that in AMNH 28272 (currently with both palatines missing) “the postpalatine torus is unossified, and the posterior rim of the canal [minor palatine foramen] is a simple notch in the rear border of the palatal surface of the palatine.” Occipital Emissary Vein Foramen.—In the dog (Evans 1993), the foramen of exit for the occipital emissary vein from the caudal cranial fossa is the mastoid foramen between the mastoid exposure of the petrosal (=mastoid process of Evans 1993) and the ex- and supraoccipital (=lateral and squamous parts of the occipital of Evans 1993). In the caudal cranial fossa of the bisected solenodon skull, AMNH 28271, a large sulcus for the occipital emissary vein runs perpendicular to the sulcus for the sigmoid sinus dorsal to the petrosal (“oev” in Fig. 21C). The occipital emissary vein sulcus ends posteriorly at a large foramen that leads into the substance of the supraoccipital bone and then to the supraoccipital foramina on the occiput (“socf” in Figs. 34, 35). In light of the position of the occipital emissary vein sulcus and foramen, it appears that both are primarily on the supraoccipital bone. Optic Foramen.—In the dog (Evans 1993), the optic foramen is centrally located in the orbitosphenoid (=orbital wing of the presphenoid of Evans 1993) and transmits the optic nerve, ophthalmic artery (=internal ophthalmic artery of Evans 1993), and the internal ophthalmic vein. In the solenodon, the optic foramen is located near the ventral limit of the orbitosphenoid (“of” in Figs. 15, 16). There is left-right asymmetry in the anteroposterior position of the optic foramen in three specimens (AMNH 185012 and 212912 and CM 18069). The solenodon optic foramen is exceedingly small; its maximum diameter is approximately one fifth the size of the sphenorbital fissure, whereas in the dog CM 30471 it is three quarters that of the orbital fissure. Orbitotemporal Canal, Anterior Opening.—In the solenodon, the orbitotemporal groove and canal in the middle cranial fossa accommodates the anterior division of the ramus superior of the stapedial artery (see Wible 1987) and accompanying veins based on MPIH 6863 (“otg” and “otc” in Fig. 21C). The orbitotemporal groove is within the parietal, except for a small contribution from the squamosal at its posterior extent based on AMNH 28272. Anteriorly, at the posterior edge of the orbitosphenoid, the groove leads into a short orbitotemporal canal, at least initially between the parietal and orbitosphenoid. The canal ends at the anterior (orbital) opening between the frontal and orbitosphenoid in AMNH 28272 (“otc” in Figs. 16, 19), in a common depression with the posterior frontal diploic vein foramen (except the left side of AMNH 28272, which lacks the venous foramen) and the posterodorsal ethmoidal foramen (except in AMNH 212912, in which the ethmoidal foramen is anterior to the depression). The orbitotemporal Wible.indd 392 canal and its orbital opening are lacking in the dog (Evans 1993) as is the anterior division of the ramus superior of the stapedial artery (Bugge 1978; Wible 1984). The history of usage for the solenodon is varied. Gregory (1910) called the orbitotemporal canal the sinus canal following Parker (1886) and identified it as a venous structure; although the orbital aperture in AMNH 28272 was labeled sinus canal (Gregory 1910: fig. 18A1; Fig. 1), supraorbital foramen was used in the text (p. 274). McDowell (1958) employed sinus canal foramen for the orbital aperture and added the middle meningeal artery en route to the ophthalmic arteries as an occupant. MacPhee (1994) used cranio-orbital foramen and identified the occupants as the sinus vein and ramus superior of the stapedial artery. The terminology followed here (orbitotemporal canal and anterior opening of the orbitotemporal canal with occupants the anterior division of the ramus superior of the stapedial artery and accompanying veins) is preferred as stated by Wible and Gaudin (2004:162) “because it best describes the position of this vascular canal and its orbital egress, and it best reflects the broader homology of these structures because it has already been applied to a broad spectrum of cynodonts (see Rougier et al. 1992).” Parietal Foramina.—In the dog (Evans 1993: fig. 12–22), parietal foramina for emissary veins off the midline in the parietal are not described but one with an emissary vein is figured. Humans have small parietal foramina that are variably present and differ in number, position, and symmetry (Boyd 1930). In the solenodon, the skulls examined have a variable number of tiny, asymmetrically arranged parietal foramina (Figs. 2, 5) except the juvenile AMNH 28272, which has none (Fig. 5). Piriform Fenestra.—Following MacPhee (1981), the piriform fenestra is the large gap in the skull base anterior to the auditory capsule present in all fetal mammals and some adults, including Solenodon. In the solenodon, the piriform fenestra (“pf” in Figs. 18, 19, 25, 26B, 28, 29) is bordered by the alisphenoid anteromedially, the squamosal anterolaterally, and the petrosal posteriorly. According to McDowell (1958), the tensor tympani muscle arises in part from the membrane of the piriform fenestra (his pyriform fenestra) and the internal carotid artery and ramus superior of the stapedial artery enter the cranial cavity via this aperture (see Fig. 26C). The course of the internal carotid artery is as noted by McDowell in AMNH 28272 and 185012 (and the left side of CM 18069), but not in AMNH 28271 and 212912, where the artery is excluded medially from the piriform fenestra by the basisphenoid in a carotid foramen (“cf” in Fig. 25), a difference that may result from developmental stage. The ramus superior of the stapedial artery in MPIH 6863 dorsal to the piriform fenestra supplies three types of branches: the anterior division traveling forward in the orbitotemporal groove, rami temporales, and the small posterior division traveling posteriorly in the posttemporal canal between the lateral surface 1/6/09 9:25:44 AM 2008 Wible—On the Cranial Osteology of Solenodon paradoxus of the pars canalicularis and squamosal. In addition, based on MPIH 6863, the piriform fenestra transmits the internal carotid nerve and veins connecting the cavernous sinus to the pterygoid veins and inferior petrosal sinus. The piriform fenestra is lacking in the adult dog as the bones there are in close contact (Evans 1993). Postglenoid Foramen.—In the dog (Evans 1993), the postglenoid foramen (=retroarticular foramen of Evans 1993) is in the squamosal (=pars squama of the temporal bone of Evans 1993) posterior to the postglenoid process (=retroarticular process of Evans 1993) and transmits the postglenoid vein (=retroarticular vein of Evans 1993). In the solenodon, the postglenoid foramen is in the squamosal posterior to the lateral end of the entoglenoid process (“pgf” in Figs. 25, 27A, 29A); a postglenoid process, such as that in the dog, is absent. Although the foramen is entirely within the squamosal, the anterior crus of the ectotympanic underlies the medial edge of the opening (Fig. 25). Posttemporal Canal, Posterior Opening.—Among extant mammals, monotremes and some therians (e.g., some didelphids, armadillos) have a posttemporal canal between the lateral surface of the pars canalicularis of the petrosal and the overlying squamosal, transmitting the posterior division of the ramus superior of the stapedial artery, the arteria diploëtica magna of Hyrtl (1853, 1854), and accompanying vein (Wible 1990; Wible and Hopson 1995; Wible and Gaudin 2004). The posttemporal canal may open on the occiput via the posterior opening of the posttemporal canal or posttemporal foramen, which is near the lateral margin of the occiput in or near the petrosquamous suture. Neither the dog (Evans 1993) nor the examined solenodons have a posttemporal foramen (see Mastoid Foramen). However, in the solenodon, MPIH 6863 has a small posterior division of the ramus superior that does not reach the occiput running with significantly larger veins between the pars canalicularis and squamosal, and AMNH 28272 has a shallow posttemporal sulcus on the posterior part of the lateral surface of the pars canalicularis, which represents the medial part of a posttemporal canal (see Fig. 30). Prootic Canal.—Among extant mammals, monotremes and some marsupials have a prootic canal through the petrosal whereby the prootic sinus, the anterior distributary of the transverse sinus, exits the cranial cavity to drain into the lateral head vein in the middle ear (Wible 1990; Wible and Hopson 1995; Sánchez-Villagra and Wible 2002; Rougier and Wible 2006). A prootic canal is widely distributed among Mesozoic mammaliaforms including Cretaceous metatherians (Wible 1990; Rougier et al. 1998). Within Eutheria, a prootic canal has only been described in isolated petrosals referred to Early Cretaceous Prokennalestes (Wible et al. 2001) and Late Cretaceous zhelestids (Ekdale et al. 2003), and in the skull of Late Cretaceous Maelestes (Wible et al. 2007, in press). In Prokennalestes Wible.indd 393 393 and non-therian mammaliaforms, the prootic canal is generally well developed and vertically oriented; in contrast, in metatherians, zhelestids, and Maelestes, the prootic canal is reduced and horizontal. The solenodon is the first placental, extant or extinct, for which a prootic canal is reported. Its prootic canal resembles that in metatherians, zhelestids, and Maelestes, that is, reduced and horizontal. The tympanic aperture (double in AMNH 28272; single in AMNH 28271 and 212912) lies on the pars canalicularis between the crista parotica and facial sulcus (“prc” in Fig. 27A); the lateral aperture, visible only on the right side of the juvenile AMNH 28272 because of postmortem displacement of the squamosal, lies on the lateral surface of the pars canalicularis in the ventral end of the vertical sulcus for the prootic sinus (see Fig. 30). Based on the bisected skull AMNH 28271, the adult differs from the juvenile in that a narrow sleeve of squamosal with a small foramen in it intervenes between the lateral aperture of the prootic canal and the sulcus for the prootic sinus; the connection is maintained by passage from the sulcus for the prootic sinus first into the small foramen in the squamosal sleeve and then into the lateral aperture of the prootic canal in the petrosal. MPIH 6863 confirms the presence of a lateral head vein “lhv” in Fig. 27B), prootic canal, and prootic sinus. Prootic Sinus Sulcus.—In the dog (Evans 1993), the transverse sinus divides into anterior and posterior distributaries, the temporal and sigmoid sinuses. The temporal sinus runs in a canal between the pars petrosa and pars squamosa of the temporal bone (=petrosal and squamosal) and exits the skull at the retroarticular foramen (=postglenoid foramen). In the bisected solenodon skull AMNH 28271, the anterior distributary of the transverse sinus first runs anteriorly in a canal between the parietal and the dorsalmost pars canalicularis of the petrosal (“ecps” in Fig. 21C) and then bends anteroventrally and then medially into a deep sulcus in the squamosal (“sps” in Fig. 21C). In the lateral wall of the canal is an opening (not visible in the figures) leading to the posterodorsal foramen for ramus temporalis on the braincase wall and in the lateral wall at the bend is on opening (“rt” in Fig. 21C) leading to the two anteroventral foramina for rami temporales on the braincase wall. Additionally, at the bend is the origination of the orbitotemporal groove. Dorsal to the postglenoid foramen, the prootic canal enters the posteromedial aspect of the sulcus (not visible in the figures). The homologies of the anterior distributary of the transverse sinus in the solenodon are at issue. Gelderen (1924) showed that the vein exiting the postglenoid foramen has a different developmental history in marsupials on the one hand and placentals on the other. In marsupials, the primary ontogenetic anterior distributary of the transverse sinus, the vena cerebralis media (=prootic sinus), and its continuation as the vena capitis lateralis (=lateral head vein) in the canalis prooticus (=prootic canal) are either reduced or lost during later ontogeny (see also Wible 1990; 1/6/09 9:25:44 AM 394 Annals of Carnegie Museum Vol. 77 Sánchez-Villagra and Wible 2002); a secondary ontogenetic anterior distributary of the transverse sinus forms, Gelderen’s vena emissaria spheno-parietalis (=sphenoparietal emissary vein), so called because it leaves the chondrocranium via the sphenoparietal fenestra anterior to the auditory capsule to reach the postglenoid foramen. In contrast, in placentals, the primary ontogenetic anterior distributary of the transverse sinus, the prootic sinus/lateral head vein pathway, is lost and replaced by a secondary ontogenetic anterior distributary, Gelderen’s vena emissaria capsulo-parietalis (=capsuloparietal emissary vein), so called because it leaves the chondrocranium via the capsuloparietal foramen dorsal to the auditory capsule to reach the postglenoid foramen. In recent years, several Cretaceous eutherians have been reported (Wible et al. 2001, 2007, in press; Ekdale et al. 2003) with an osteological pattern closely resembling that of some marsupials (and other metatherians), that is, a sulcus for the prootic sinus on the lateral surface of the pars canalicularis of the petrosal confluent with a small prootic canal. Reported here is the discovery of this osteological pattern in the solenodon. The developmental history of the solenodon vessels is not known and without that knowledge, the implications of the discovery of this osteological pattern are uncertain. The author intends to pursue this topic, but of immediate concern is a terminological issue regarding the anterior distributary of the transverse sinus in the solenodon. For now, given that a similar osteological pattern occurs in various Cretaceous and Paleocene metatherians (Wible 1990; Rougier et al. 1998; Ladevèze 2004, 2007; Ladevèze and Muizon 2008), various extant marsupials (Wible 1990; SánchezVillagra and Wible 2002), various Cretaceous eutherians (Wible et al. 2001, 2007, in press; Ekdale et al. 2003), and the solenodon, it is judicious to apply the same terminology for the osteological correlates with the explicit caveat that this is under review. Applying the metatherian/ Cretaceous eutherian terminology, AMNH 28271 has an anteriorly directed endocranial canal for the prootic sinus dorsally between the parietal and petrosal, then a ventrally directed endocranial sulcus for the prootic sinus between the squamosal and petrosal and ventrally just within the squamosal. In the last segment is a foramen in the squamosal connecting to the prootic canal in the petrosal. Ventral to the prootic canal connection, the short segment of the sulcus dorsal to the postglenoid foramen is for another vein, which is called here the postglenoid vein to be congruent with the name of its foramen of exit. Pterygoid Canal.—In the dog (Evans 1993), the caudal opening into the small pterygoid canal is in the suture between the basisphenoid and posterodorsal margin of the pterygoid bone on the skull base, and the rostral opening is in the caudal pterygopalatine fossa anteroventral to the sphenorbital fissure (orbital fissure of Evans 1993) between the pterygoid and the pterygoid process of the sphenoid (the ventral projection of the sphenoid that abuts the pterygoid bone). It transmits the nerve of the pterygoid Wible.indd 394 canal and occasionally a small artery off the maxillary artery. In the solenodon, the caudal opening of the small pterygoid canal (=vidian canal of MacPhee 1994) is between the caudal process of the pterygoid and basisphenoid at the anteromedial corner of the piriform fenestra, based on AMNH 28272 and MPIH 6863 (“pc” in Figs. 19, 25, 27A). The rostral opening is deep within the cavum epiptericum, the extradural space within the cranial cavity housing the trigeminal ganglion (Gaupp 1902, 1905), at the level of the transverse canal foramen in the side of the basisphenoid and is only visible through the sphenorbital fissure. A probe pushed into the caudal opening of the pterygoid canal in the bisected skull AMNH 28271 appears in the transverse sinus canal within the basisphenoid and then into the rear of the fossa for the trigeminal ganglion. In MPIH 6863, the pterygoid canal is separate from (and passes ventral to) the transverse sinus canal. Based on (unspecified) specimens with dried arteries in place, McDowell (1958:129) identified an artery of the pterygoid canal off the internal carotid artery (his vidian branch of the arteria promontorii), which “passes through the basisphenoid or perhaps, between basisphenoid and alisphenoid) to emerge in the cranial cavity, lateral to the pituitary fossa. To this extent it is like the main carotid of marsupials and therapsid reptiles, but the significance of this is uncertain.” MacPhee (1981) noted that MPIH 6863 lacks such an artery and only vein accompanies nerve into the pterygoid canal from behind. Ramus Inferior Sulcus.—In the solenodon, based on MPIH 6863, the ramus inferior of the stapedial artery (see also McDowell 1958) and lesser petrosal nerve occupy a sulcus on the posterior slope of the alisphenoid tympanic process in their course between the piriform fenestra and foramen ovale (“gri” in Figs. 25, 27A; “ri” in Fig. 26C). The composition of this sulcus differs in the juveniles AMNH 28272 and 185012, the only forms preserving a suture here; in the former the alisphenoid and squamosal contribute equally (Figs. 18, 27A), but in the latter it is nearly entirely alisphenoid (Fig. 25). This difference may result from the difference in developmental stages between the two juveniles. In the dog, the ramus inferior is reported to be absent (Wible 1984). Secondary Facial Foramen.—see Facial Canal and/or Sulcus. Sigmoid Sinus Sulcus.—In the dog (Evans 1993:710), the sigmoid sinus “is the roughly S-shaped caudoventral continuation of the transverse sinus. It begins by forming an arc around the proximal end of the petrous temporal bone [=petrosal]. The first arc is continued by the second arc, which lies medial to the petro-occipital synchondrosis. The sinus terminates after traversing the jugular foramen by continuing as the internal jugular vein.” In the bisected solenodon skull, AMNH 28271, the sulcus for the sigmoid sinus lies dorsal to the subarcuate fossa in the caudal 1/6/09 9:25:44 AM 2008 Wible—On the Cranial Osteology of Solenodon paradoxus cranial fossa (“sss” in Fig. 21C). Anteriorly, the sulcus is largely on the parietal with a minor contribution from the pars canalicularis of the petrosal; posteriorly this relationship is reversed. At the posterodorsal corner of the petrosal the supraoccipital makes a minor contribution to the dorsal margin of the sulcus, which bends ventrally and ends at the condyloid canal in the supraoccipital; the sulcus does not extend to the jugular foramen. In light of the size of the condyloid canal, it represents the primary exit for the sigmoid sinus. Sphenopalatine Foramen.—In the dog (Evans 1993), the sphenopalatine foramen is within the perpendicular lamina of the palatine dorsal to the caudal palatine foramen. It connects the pterygopalatine fossa and the nasal cavity, and transmits the caudal nasal nerve and sphenopalatine artery and vein. In the solenodon, a separate caudal palatine foramen is lacking and its contents, the major palatine nerve, artery, and vein in the dog, are transmitted via the sphenopalatine foramen. In the juvenile solenodon AMNH 28272, the only specimen preserving complete sutural information on the sphenopalatine foramen, this opening is between the ethmoid, maxilla, and palatine (see “spf” in Fig. 10); after a short rostrally directed canal it opens anteriorly within the nasopharyngeal meatus based on AMNH 28271 (“spf” in Fig. 22). Sphenorbital Fissure.—In the dog (Evans 1993), the sphenorbital fissure (=orbital fissure of Evans 1993) is located between the orbito- and alisphenoid (orbital and temporal wings of the sphenoid of Evans 1993), sandwiched between the optic foramen and the rostral opening of alisphenoid canal (=rostral alar foramen of Evans 1993). It transmits the oculomotor, trochlear, ophthalmic, and abducens nerves, the anastomotic artery connecting the maxillary and internal carotid arteries, and the ophthalmic venous plexus. In the solenodon, the sphenorbital fissure is between the orbito- and alisphenoid, somewhat separated from the optic foramen and alisphenoid canal (“sof” in Figs. 14–16). According to Gregory (1910), it transmits the oculomotor, trochlear, ophthalmic, maxillary, and abducens nerves. It most likely also transmits arteries and veins, the ramus infraorbitalis and ophthalmic veins. One of the reviewers (G.W. Rougier) noted a problem with the use of the term sphenorbital fissure as employed by this author for the aperture both in marsupials (e.g., Monodelphis, Wible 2003) and in placentals (this report). In the former, the sphenorbital fissure transmits the optic nerve, but in latter it does not, because the optic nerve is enclosed in a separate foramen. The developmental processes accounting for this difference have been summarized by numerous authors (e.g., Kuhn 1971; Moore 1981; Kuhn and Zeller 1987; Zeller 1989; Novacek 1993), but there appears to be no consensus on the naming of the resulting openings other than that for the optic nerve. At least since Gregory (1910), the tradition has been to employ sphenorbital fissure for the differing apertures in placentals and marsupials. Wible.indd 395 395 Stapedial Artery Sulcus.—The stapedial artery is a branch of the internal carotid artery that among extant adult mammals occurs in the platypus and various placentals (Tandler 1899, 1901; Bugge 1974; Wible 1987). In the placentals, the stapedial artery often occupies a sulcus on the promontorium of the petrosal aimed at the fenestra vestibuli (Wible 1987). In the solenodon, based on MPIH 6863, the stapedial artery sulcus has two separate parts: medial and anterolateral to the fenestra vestibuli. The medial part arises about a millimeter medial to the fenestra vestibuli on the promontorium from the (internal) carotid sulcus and crosses the posterior half of that opening’s ventral rim (“gsa” in Fig. 26B). The anterolateral part, also a millimeter long, extends between the level of the secondary facial foramen and the back of the piriform fenestra on the tegmen tympani (“gsa” in Fig. 27A). Between these two sulci, the stapedial artery penetrates the stapedial foramen in the stapes and runs ventral to the facial nerve in the facial sulcus (“sa” in Fig. 26C). At is origin on the promontorium, the stapedial artery sulcus is comparable in width to the carotid sulcus. The stapedial artery (Tandler 1899; Bugge 1978) and sulcus (Evans 1993) are lacking in the adult dog. Stylomastoid Notch/Foramen.—In the dog (Evans 1993), the stylomastoid foramen is deeply recessed ventral to the mastoid exposure of the petrosal (=mastoid process of Evans 1993) and dorsal to the caudal part of the auditory bulla; it transmits the facial nerve and the stylomastoid artery off the caudal auricular artery, a branch of the external carotid. In the solenodon, the stylomastoid foramen is a notch open posteriorly and posteromedially; the notch is bordered laterally by the posterior continuation of the crista parotica, anteriorly by the tympanohyal, and anteromedially by the lateral section of the caudal tympanic process (“smn” in Figs. 25, 27A). In MPIH 6863, the stylomastoid notch transmits the facial nerve (“fn” in Fig. 27B), a branch of the ramus posterior of the stapedial artery (MacPhee 1981), and a small vein off the lateral head vein. Following Klaauw (1931), two types of stylomastoid foramina are often identified: the foramen stylomastoideum primitivum and definitivum. The former occurs as a notch in fetal mammals and some adults, including solenodon, whereby the point of exit is between the tympanohyal and pars canalicularis of the petrosal with contributions likely also from the ectotympanic and stylohyal; the latter occurs in mammals with inflated bulla (e.g., the dog), whereby the point of exit is at the end of a canal in the bulla distal to the fetal aperture. Suboptic Foramen.—In the solenodon, according to Gregory (1910:248), “the suboptic foramen is located just below the optic foramen; its canal runs downward and backward to the transverse sinus in the presphenoid.” All solenodon specimens have a suboptic foramen (“sbof” in Figs. 15, 19), but the number and position varies considerably within and between specimens with a maximum of six on the left side of AMNH 28272 and a minimum of one on the left side 1/6/09 9:25:44 AM 396 Annals of Carnegie Museum Vol. 77 of AMNH 28271. In AMNH 28272 and 185012, the only specimens to preserve sutural information in the orbit, the suboptic foramina are entirely within the orbitosphenoid (Fig. 19). Continuity between the suboptic foramen and the transverse sinus canal in the presphenoid was confirmed in AMNH 28271. The dog (Evans 1993) does not have a suboptic foramen. Supra-ethmoid Foramen.—see Foramen for Frontal Diploic Vein. Suprameatal Foramen.—A suprameatal foramen within the squamosal dorsal to the external acoustic meatus and ventral to the suprameatal crest (Novacek 1986a; Wible 2003; Wible et al. 2004) is lacking in the dog (Evans 1993). In the solenodon, one or more small suprameatal foramina (subsquamosal foramina of Gregory 1910; “f.sb.sq.” in Fig. 1) are found in the squamosal inferior to the suprameatal crest in the vicinity of the roof of the external acoustic meatus and posttympanic crest (“smef” in Figs. 24, 27A). In MPIH 6863, a tiny suprameatal foramen transmits a branch of the ramus posterior of the stapedial artery into the substance of the squamosal (see Fig. 26C). Supraoccipital Foramina.—In the dog (Evans 1993: figs. 12–21, 12–22), an unnamed foramen in the supraoccipital (=squamous part of the occipital of Evans 1993) for a venous connection between the transverse sinus and occipital emissary vein is illustrated, but not described in the text. In the solenodon, the number, size, and position of foramina in the supraoccipital bone varies (“socf” in Figs. 34, 35). In AMNH 28272 a centrally positioned heart-shaped depression contains a half dozen smaller openings; in AMNH 185012 there are two larger openings per side, well off the midline, and a number of smaller openings; and in AMNH 212912 and CM 18069, an ovoid depression just to the left of the external occipital crest contains several smaller openings as well as an additional dozen small openings arrayed across the occiput. All openings are presumably outlets for the occipital emissary vein, but this cannot be verified in MPIH 6863 because of lack of preservation. Supra-optic Foramen.—In the solenodon, according to Gregory (1910:248), the supra-optic foramen (above the optic foramen) “runs downward and backward and joins the suboptic” foramen, which in turn “runs downward and backward to the transverse sinus in the presphenoid.” Although the opening that Gregory labeled as the supra-optic foramen in AMNH 28272 is the posterodorsal ethmoidal foramen of this report (cf. Figs. 1, 19), this specimen has a small foramen within the frontal anteromedial to the posterodorsal ethmoidal foramen that likely is a supra-optic foramen based on the definition of Gregory (“s-of” in Fig. 19). A probe passed into a similarly situated foramen on the right side of AMNH 28271 reaches the transverse sinus canal in the presphenoid. Sutures are lacking in AMNH 28271, but it is doubtful that this foramen is entirely within the frontal and the orbitosphenoid likely contributes. A supra-optic Wible.indd 396 foramen also occurs in CM 18069 (“4” in Fig. 15), but is lacking in AMNH 185012 and 212912. Transverse Canal Foramen.—In the solenodon, each side of the bisected skull AMNH 28271 has an opening on the cut edge of the basisphenoid for a vein crossing the midline based on MPIH 6863 (“tsc” in “bs” in Fig. 21C). The principal exit of this vein is via the transverse canal foramen (transverse canal of Gregory 1910), posterior to but in a common depression with the alisphenoid canal (“tcf” in Figs. 15, 16, 19). Two others exits are evident: in the ventral surface of the basisphenoid in or near the pterygoid suture based on AMNH 28272 (Fig. 19) and in the dorsolateral surface of the basisphenoid within the cranial cavity (lacking in AMNH 185012). Gregory (1910) reported a second transverse sinus in the presphenoid, the opening of which is preserved in the cut edges of that bone in AMNH 28271 (“tsc” in “ps” in Fig. 21C). According to Gregory (1910) and confirmed here, two types of foramina connect to the presphenoid transverse sinus: supra-optic and suboptic. A transverse canal foramen and the presphenoid and basisphenoid transverse sinuses are absent in the dog (Evans 1993). Tympanic Canaliculus.—In the dog (Evans 1993: fig. 19– 20), the course of the tympanic nerve is illustrated but not described in the text. As figured, it arises from the glossopharyngeal nerve beneath the jugular foramen and runs laterally into the middle ear between the pars cochlearis and auditory bulla, through the tympanic canaliculus of NAV (1994). In the solenodon, MacPhee (1981) reported a small tympanic canaliculus in the caudal tympanic process in MPIH 6863, but in the current report this process is identified as the rostral tympanic process because it arises from the pars cochlearis (“tca” in Figs. 25, 27A). Ventral Condyloid Foramen.—In the solenodon, the ventral condyloid fossa between the occipital condyle and faint paracondylar process on the exoccipital’s horizontal process has two or more small foramina that connect to the condyloid canal (“vcf” in Fig. 26B). One specimen, AMNH 28271, has an additional large opening bilaterally. In the dog (Evans 1993), ventral condyloid foramina are not reported or illustrated. Vestibular Aqueduct.—In the dog (Evans 1993:143), the endolymphatic duct enters into the petrosal (=pars petrosa of the temporal bone of Evans 1993) via the opening of the vestibular aqueduct, which “is located caudodorsal to the opening of the cochlear canaliculus in a small but deep cleft.” In the solenodon AMNH 28271, the vestibular aqueduct is similarly situated (“av” in Figs. 21C, 22). However, whereas the vestibular aqueduct is smaller than the cochlear canaliculus in the dog (Evans 1993), the reverse is the case in AMNH 28271. 1/6/09 9:25:44 AM 2008 Wible—On the Cranial Osteology of Solenodon paradoxus 397 Appendix 1. List of Anatomical Terms. The terms used here are to the left with references; synonyms and/or Nomina Anatomica Veterinaria (NAV) equivalents to the right.The * indicates structures discussed in the text but absent in Solenodon paradoxus (e.g., caudal palatine foramen). Abducens Nerve (= Cranial Nerve VI)—Nervus abducens (NAV) Accessory Nerve (= Cranial Nerve XI)—Nervus accessorius (NAV) Accessory Palatine Foramen—(Wible and Rougier 2000); Middle Palatine Foramen (Novacek 1986); Minor Palatine Foramen (Evans 1993) Accessory Palatine Nerve—Nevus palatinus accessorius (NAV) Ala temporalis—(De Beer 1937) Alae of Vomer—Alae vomeris (NAV) Alicochlear Commissure—(De Beer 1937; MacPhee 1981) Alisphenoid—Os basisphenoidale, Ala temporalis (NAV) Alisphenoid Canal—(Gregory 1910); Canalis alaris (NAV) Alveolar Canal—Canalis alveolaris (NAV) Alveolar Foramina—Foramina alveolaria (NAV) Alveolar Margin—Margo alveolaris (NAV) Alveolar Process of Maxilla—Os maxillare, Processus alveolaris (NAV) Alveolar Process of Premaxilla—Os incisivum, Processus alveolaris (NAV) Alveoli—Alveoli dentales (NAV) Ampulla of Lateral Semicircular Canal—Ampulla ossea lateralis (NAV) Ampulla of Posterior Semicircular Canal—Ampulla ossea posterior (NAV) Anastomotic Artery*—Arteria anastomotica (Wible 1987; Evans 1993) Angle of Mandible—Mandibula, Angulus mandibulae (NAV) Angle of Stylohyal—Angulus stylohyoideus (NAV) Angular Process—Processus angularis (NAV) Annular Ridge of Frontal—(Rowe et al. 2005) Anterior Crus of Ectotympanic—Annulus tympani, Crus anterior (NAV) Anterior Crus of Stapes—Stapes, Crus rostrale (NAV) Anterior Division of Ramus Superior of Stapedial Artery—(Wible and Gaudin 2004) Anterior Opening, Orbitotemporal Canal—(Rougier et al. 1992); Supraorbital Foramen (Gregory 1910); Sinus Canal Foramen (McDowell 1958); Foramen for Ramus Supraorbitalis (Wible 1987); Cranio-Orbital Foramen (MacPhee 1994) Anterior Pole of Promontorium—(Wible et al. 2001) Anterior Semicircular Canal—Canalis semicircularis anterior (NAV) Anteroventral Ethmoidal Foramen—this study Antorbital Fossa—(Novacek 1986) Aperture of Cochlear Fossula—(MacPhee 1981) Aqueductus Vestibuli—(NAV) Arteria diploëtica magna—(Hyrtl 1853, 1854; Wible 1987) Artery of Pterygoid Canal*—(Evans 1993); Vidian Artery (McDowell 1958) Auditory Bulla—Bulla tympanica (NAV) Auditory Capsule—Capsula otica (NAV) Auditory Ossicles—Ossicula auditus (NAV) Auditory Tube—Tuba auditiva (NAV); Eustachian Tube (Gregory 1910) Auricular Ramus of Vagus Nerve—Nervus vagus, Ramus auricularis (NAV) Axis—(NAV) Basal Lamina of Ethmoid—Os ethmoidale, Lamina basalis (NAV) Basal Lamina of Ventral Nasal Concha—(Evans 1993) Basicranium—Basis cranii interna et externa (NAV) Basihyal—Basihyoideum (NAV) Basioccipital—Os occipitale, Pars basilaris (NAV) Basipharyngeal Canal—(Evans 1993) Basisphenoid—Os basisphenoidale, Corpus (NAV) Body of Incus—Corpus incudis (NAV) Body of Mandible—Corpus mandibulae (NAV) Brain—Encephalon (NAV) Braincase—Calvaria (NAV) Canines—Dentes canini (NAV) Canal for Modiolus—(Terry 1942) Wible.indd 397 Capitular Crest of Malleus—(Henson 1961) Capitular Spine of Malleus—(Henson 1961) Capsuloparietal Emissary Vein*—(Gelderen 1924); Sinus temporalis (NAV) Capsuloparietal Foramen—(Gelderen 1924); Fissura occipitocapsularis superior (De Beer 1937) Carnassial Tooth*—(Evans 1993); Dens sectorius (NAV) Carotid Canal*—(Evans 1993); Canalis caroticus (NAV) Carotid Foramen—(Wible and Gaudin 2004); Canalis caroticus (NAV); Foramen lacerum medium (Gregory 1910) Carotid Sulcus—Sulcus caroticus (NAV) Cartilaginous Nasal Septum—Cartilago septi nasi (NAV) Caudal Auricular Artery—Arteria auricularis caudalis (NAV) Caudal Cranial Fossa—Fossa cranii caudalis (NAV); Occipital Cranial Fossa (Evans 1993) Caudal Meningeal Artery—Arteria meningea caudalis (NAV) Caudal Nasal Nerve—Nervus nasalis caudalis (NAV) Caudal Opening of Pterygoid Canal—(Wible and Gaudin 2004); Vidian Foramen (McDowell 1958) Caudal Palatine Foramen*—(Evans 1993); Foramen palatinum caudale (NAV) Caudal Process of Pterygoid—(Giannini et al. 2006) Caudal Process of Squamosal—this study Caudal Tympanic Process of Petrosal—(MacPhee 1981) Cavernous Sinus—Sinus cavernosus (NAV) Cavum Epiptericum—(Gaupp 1902, 1905; De Beer 1937) Cavum Supracochleare—(Voit 1909; De Beer 1937); Geniculum canalis facialis (NAV) Central Buttress of Malleus—(Henson 1961) Ceratohyal—Ceratohyoideum (NAV) Cerebellum—(NAV) Cerebral Hemisphere—Cerebrum (NAV) Choanae—(NAV) Chorda Tympani Nerve—Chorda tympani (NAV) Circular Fissure—(Rowe et al. 2005) Cleidomastoid Muscle—(Allen 1910); Musculus cleidomastoideus (Evans 1993) Cochlear Canaliculus—(MacPhee 1981); Apertura externa canaliculus cochleae (NAV); Aqueductus cochleae (Evans 1993) Cochlear Duct—Ductus cochlearis (NAV) Cochlear Fossula—(MacPhee 1981) Cochlear Nerve—Nervus cochlearis (NAV) Common Nasal Meatus—Meatus nasi communis (NAV) Conchal Crest—Crista conchalis (NAV) Condylar Process—Processus condylaris (NAV) Condyloid Artery—(Evans 1993); Arteria condylaris (NAV) Condyloid Canal—(Evans 1993); Canalis condylaris (NAV); Venous Condylar Foramen (Gregory 1910) Condyloid Vein—(Evans, 1993) Coronoid Crest—Crista coronoidea (Evans 1993) Coronoid Process—Processus coronoideus (NAV) Craniopharyngeal Canal—(Evans 1993) Cranium—NAV Cribroethmoidal Foramen—(Moore 1981); Ethmoidal Foramen (Sisson 1910); Ethmoidal Fissure (Terry 1942) Cribriform Plate of Ethmoid—Os ethmoidale, Lamina cribrosa (NAV) Cricoid Cartilage—Cartilago cricoidea (NAV) Crista Frontalis—(NAV) Crista Galli of Ethmoid*—Os ethmoidale, Crista galli (NAV) Crista Interfenestralis—(Wible et al. 1995) Crista Parotica—(De Beer 1937) Crista Petrosa—(Wible 1990); Crista parties petrosae (NAV) Crista Stapedis—(Henson 1961) Crista Supramastoidea—(NAV) Crista Tympanica—(MacPhee 1981) 1/6/09 9:25:44 AM 398 Annals of Carnegie Museum Vol. 77 Appendix 1., continued Crural Sulcus of Stapes—(Henson 1961) Crus Breve of Incus—Incus, Crus breve (NAV) Crus Commune of Semicircular Canals—(Wible 1990); Crus osseum commune (NAV) Crus Longum of Incus—Incus, Crus longum (NAV) Deciduous Teeth—Dentes decidui (NAV) Diastema—(NAV) Digastric Muscle—Musculus digastricus (NAV) Diploë—(NAV) Dorsal Condyloid Foramina—(Wible and Gaudin 2004) Dorsal Condyloid Fossa—Fossa condylaris dorsalis (NAV) Dorsal Nasal Meatus—Meatus nasi dorsalis (NAV) Dorsum Sellae—(NAV) Dura Mater—Dura mater encephali (NAV) Ectopterygoid Process*—(Giannini et al. 2006); Ectopterygoid Lamina (McDowell 1958); Ectopterygoid Crest (Novacek 1986) Ectoturbinates—(Smith and Rossie 2006); Ectoturbinalia (NAV) Ectotympanic—(MacPhee 1981); Annulus tympanicus (NAV); Tympanic (Gregory 1910) Embrasure—Septa interalveolaria (NAV) Endocranial Canal for Prootic Sinus—this study Endocranium—Cavum cranii (NAV) Entoglenoid Capitular Facet of Glenoid Fossa—Postglenoid Capitular Facet of Glenoid Fossa (McDowell 1958) Entoglenoid Facet of Mandibular Condyle—Postglenoid Facet of Mandibular Condyle (McDowell 1958) Entoglenoid Process of Squamosal—(McDowell 1958); Postglenoid Process (Allen 1910); Post-Glenoid (Entoglenoid) Process (Gregory 1910); Modified Entoglenoid Process (McDowell 1958; MacPhee 1981), Pseudopostglenoid (Entoglenoid) Process (Novacek 1986a); Pseudoglenoid Process (MacPhee 1994) Endolymphatic Duct—Ductus endolymphaticus (NAV) Entopterygoid Process—(Giannini et al. 2006); (Internal) Pterygoid Lamina (McDowell 1958); Entopterygoid Crest (Novacek 1986) Entotympanic*—(Klaauw 1922); Os temporale, Pars endotympanica (NAV) Epihyal—Epihyoideum (NAV) Epitympanic Recess—(Klaauw 1931); Recessus epitympanicus (NAV) Epitympanic Wing of Petrosal—(MacPhee 1981) Ethmoid—Os ethmoidale (NAV) Ethmoidal Foramen—Foramen ethmoidale (NAV); Ethmoid Foramen (Gregory 1910) Ethmoidal Fossae—Fossae ethmoidales (NAV) Ethmoidal Nerve—Nervus ethmoidalis (NAV) Ethmoturbinate I—(Smith and Rossie 2006); Endoturbinalia II (Evans 1993) Ethmoturbinate II—(Smith and Rossie 2006); Endoturbinalia III (Evans 1993) Ethmoturbinate III—(Smith and Rossie 2006); Endoturbinalia IV (Evans 1993) Ethmoturbinate IV—(Smith and Rossie 2006) Ethmoturbinates—(Smith and Rossie 2006); Ethmoturbinalia (NAV) Exoccipital—Os occipitale, Pars lateralis (NAV) Exoccipital Crest—(Gaudin 1995) External Acoustic Meatus—Meatus acusticus externus (NAV); External Auditory Meatus (Gregory 1910) External Capitular Facet of Glenoid Fossa—(McDowell 1958) External Carotid Artery—Arteria carotis externa (NAV); Ectocarotid Artery (Gregory 1910) External Ethmoidal Artery—Arteria ethmoidalis externa (NAV) External Ethmoidal Vein—Vena ethmoidalis externa (NAV) External Facet of Manidbular Condyle—(McDowell 1958) External Lamina of Ethmoid—(Evans 1993); Os ethmoidale, Lamina tectoria + Lamina orbitalis + Lamina basalis (NAV) External Nasal Aperture—Apertura nasi ossea (NAV); External Nasal Opening or Piriform Aperture (Evans 1993) Wible.indd 398 External Occipital Crest—Crista occipitalis externa (NAV) Eyelids—Palpebrae (NAV) Facet for Ectotympanic on Squamosal—(Wible et al. 2004) Facet for Malleus on Petrosal—this study Facet for Tympanic Process of Petrosal on Ectotympanic—(McDowell 1958) Facial Canal—(MacPhee 1981); Canalis facialis (NAV); Fallopian Aqueduct (McDowell 1958) Facial Nerve (= Cranial Nerve VII)—Nervus facialis (NAV) Facial Process of Lacrimal—Os lacrimale, Facies facialis (NAV) Facial Process of Premaxilla—Os incisivum, Facies labialis (NAV) Facial Sulcus—(MacPhee, 1981) Facial Surface of Maxilla—Os maxillare, Facies facialis (NAV) Falx Cerebri—(NAV) Fenestra Cochleae—(NAV); Fenestra Rotunda (McDowell 1958) Fenestra Vestibuli—(NAV); Fenestra Ovalis (Gregory 1910) Footplate (= Base) of Stapes—Stapes, Basis stapedis Foramen Acusticum Inferius—(Sisson 1910); Ventral Vestibular Area (Evans 1993) Foramen Acusticum Superius—(Sisson 1910); Facial Canal + Dorsal Vestibular Area (Evans 1993) Foramen Centrale Cochleare—(Terry 1942) Foramen for Chorda Tympani Nerve of Malleus—(Henson 1961) Foramen for Inferior Petrosal Sinus—(Wible 1983) Foramen for Occipital Emissary Vein—this study Foramen for Ramus Temporalis—(Wible and Gaudin 2004); Post Parietal Foramen; Post-Squamosal Foramen (Gregory 1910); Subsquamosal Foramen(Wible et al. 2004) Foramen Magnum—(NAV) Foramen Ovale—(NAV) Foramen Rotundum*—(NAV) Foramen Singulare—(NAV) Foramen Spinosum*—(NAV) Foramen Stylomastoideum Definitivum*—(McDowell 1958) Foramen Stylomastoideum Primitivum—(McDowell 1958) Fossa for Lacrimal Sac—Fossa sacci lacrimalis (NAV) Fossa for Stapedius Muscle—(McDowell 1958); Fossa m. stapedius (Evans, 1993) Fossa for Tensor Tympani Muscle—(MacPhee, 1981); Fossa m. tensor tympani (Evans, 1993) Fossa Incudis—(MacPhee 1981) Frontal—Os frontale (NAV) Frontal Diploic Vein—Vena diploica frontalis (NAV) Frontal Diploic Vein Foramen—(Thewissen 1989); Supra-Ethmoid Foramen (Gregory 1910); Frontal Diploic Foramen (MacPhee 1994) Frontal Sinus—Sinus frontalis (NAV) Frontoethmoidal Suture—Sutura frontoethmoidalis (NAV) Fundus of Nasal Fossa—(Evans 1993) Geniculate Ganglion—Ganglion geniculi (NAV) Glaserian Fissure—(MacPhee 1981); Fissura Glaseri (Klaauw 1931) Glenoid Area of Squamosal—this study Glenoid Fossa—Fossa mandibularis (NAV); Retroarticular Fossa (Evans 1993) Glossopharyngeal Nerve (= Cranial Nerve IX)—Nervus glossopharyngeus (NAV) Greater Petrosal Nerve—Nervus petrosus major (NAV); Great Superficial Petrosal Nerve (McDowell 1958) Groove for Auditory Tube—(Wible 2003) Groove for Chorda Tympani Nerve of Malleus—(Henson 1961) Groove for Chorda Tympani Nerve of Squamosal—(McDowell 1958) Groove for Internal Carotid Artery—(Wible 1986) Groove for Postglenoid Vein—this study Groove for Ramus Inferior of StapedialArtery—(Wible 1987) Groove for Rostral Process of Malleus of Ectotympanic—Groove for Folian Process of Malleus of Ectotympanic (McDowell 1958) 1/6/09 9:25:44 AM 2008 Wible—On the Cranial Osteology of Solenodon paradoxus 399 Appendix 1., continued Groove for Stapedial Artery—(Wible 1987) Hard Palate—Palatum osseum (NAV) Head of Malleus—Caput mallei (NAV) Head of Stapes—Caput stapedis (NAV) Hiatus Fallopii—(McDowell 1958); Petrosal Canal (Evans 1993) Horizontal Part of Exoccipital—(Wible 2003) Horizontal Part of Vomer— (Evans 1993) Horizontal Process of Palatine—Os palatinum, Lamina horizontalis (NAV) Horizontal Sulcus of Cribriform Plate—this study Hyoid Apparatus—Apparatus hyoideus (NAV) Hypoglossal Foramen—Canalis n. hypoglossum (NAV); Condylar Foramen (Gregory 1910); Foramen hypoglossi (Evans 1993) Hypoglossal Nerve (= Cranial Nerve XII)—Nervus hypoglossus (NAV) Hypoglossal Vein—Vena canalis hypoglossi (Evans 1993) Hypophyseal Fossa—Fossa hypophysealis (NAV); Pituitary Fossa or Depression (Gregory 1910) Hypophysis—(NAV); Pituitary Body (Gregory 1910) Incisive Foramen—Fissura palatina (NAV) Incisive Incisure of Vomer— (Evans 1993) Incisivomaxillary Canal—Canalis maxilloincisivus (Evans 1993) Incisors—Dentes incisivi (NAV) Incudomallear Joint—Articulation incudomallearis (NAV) Incudostapedial Joint—Articulation incudostapedia (NAV) Incus— (NAV) Inferior Alveolar Artery—Arteria alveolaris inferior (NAV); Mandibular Alveolar Artery (Evans 1993) Inferior Alveolar Nerve—Nervus alveolaris inferior (NAV); Mandibular Alveolar Nerve (Evans 1993) Inferior Alveolar Vein—Vena alveolaris inferior (NAV); Mandibular Alveolar Vein (Evans 1993) Inferior Articular Facet of Malleus—(Henson 1961) Inferior Articular Surface of Incus—(Henson 1961) Inferior Oblique Muscle—Musculus obliquus ventralis (NAV) Inferior Petrosal Sinus—Sinus petrosus ventralis (NAV) Inferior Vestibular Area—(Terry 1942); Area vestibularis superior (NAV) Infraorbital Artery—Arteria infraorbitalis (NAV) Infraorbital Canal—Canalis infraorbitalis (NAV) Infraorbital Foramen—Foramen infraorbitale (NAV) Infraorbital Nerve—Nervus infraorbitalis (NAV) Infraorbital Vein—Vena infraorbitalis (NAV) Inner Lamella of Malleus—(Henson 1961) Interfrontal Suture—Sutura interfrontalis (NAV) Intermaxillary Suture—Sutura intermaxillaris (Evans, 1993); Rostral Part of Sutura palatina mediana (NAV) Internal Acoustic Meatus—Meatus acusticus internus (NAV); Internal Auditory Meatus (Gregory 1910) Internal Carotid Artery—Arteria carotis interna (NAV); Entocarotid Artery (Gregory 1910); Arteria promontorii (McDowell 1958) Internal Carotid Nerve—Nervus caroticus interna (NAV) Internal Jugular Vein—Vena jugularis interna (NAV) Internasal Suture—Sutura internasalis (NAV) Interpalatine Suture—Caudal Part of Sutura palatina mediana (NAV) Interparietal—Os interparietale (NAV) Intersphenoidal Synchondrosis—Synchondrosis intersphenoidalis (NAV) Jugal*—Os zygomaticum (NAV); Malar (Gregory 1910) Jugular Foramen—Foramen jugulare (NAV) Jugular Incisure—Incisura jugularis (NAV) Jugular Process of Exoccipital—Processus jugularis (NAV) Jugum Sphenoidale—(NAV) Lacrimal—Os lacrimale (NAV); Lachrymal (Gregory 1910) Wible.indd 399 Lacrimal Duct—Canaliculus lacrimalis (NAV) Lacrimal Fenestra—(Wible and Gaudin 2004) Lacrimal Foramen—Foramen lacrimale (NAV) Lacrimal Sac—Saccus lacrimalis (NAV) Lacrimal Tubercle*—(McDowell 1958) Lateral Laminae of Vomer—Laminae lateralis of Vomer (Evans, 1993) Larynx—(NAV) Lateral Aperture of Prootic Canal—(Wible 2003) Lateral Head Vein—(Wible 1990; Wible and Hopson 1995; Rougier and Wible 2006) Lateral Head Vein Sulcus—Groove for Lateral Head Vein (Wible and Hopson 1995) Lateral Laminae of Vomer—(Evans 1993) Lateral Mass of Ethmoid—(Evans 1993); Os ethmoidale, Labyrinthus ethmoidalis (NAV) Lateral Process of Malleus—Malleus, Processus lateralis (NAV) Lateral Pterygoid Muscle—Musculus pterygoideus lateralis (NAV) Lateral Section of Caudal Tympanic Process—(MacPhee 1981) Lateral Semicircular Canal—Canalis semicircularis lateralis (NAV) Lenticular Process of Incus—Incus, Processus lenticularis (NAV) Lesser Petrosal Nerve—Nervus petrosus minor (NAV) Levator Labii Superioris Proprius—(Whidden 2002); Musculus levator labii superioris (NAV) Lingual Nerve—Nervus lingualis (NAV) Longus Capitis Muscle—Musculus longus capitis (NAV) Major Palatine Artery—Arteria palatina major (NAV) Major Palatine Foramen—Foramen palatinum majus (NAV); Anterior Palatine Foramen (Gregory 1910) Major Palatine Nerve—Nervus palatinus major (NAV) Major Palatine Vein—Vena palatinus major (NAV) Mallear Facet on Crista Parotica—this study Malleus—(NAV) Mandible—Mandibula (NAV) Mandibular Canal—Canalis mandibulae (NAV) Mandibular Foramen—Foramen mandibulae (NAV) Mandibular Nerve—Nervus mandibularis (NAV) Mandibular Symphysis— (Evans 1993) Manubrium of Malleus—Manubrium mallei (NAV) Masseter Muscle—Musculus massetericus (NAV) Masseteric Fossa—Fossa masseterica (NAV) Mastoid Canaliculus—(NAV); Passage for Auricular Nerve (McDowell 1958) Mastoid Exposure of Petrosal—(Wible 2003); Processus mastoideus (NAV); Mastoid Portion of Periotic (Gregory 1910) Mastoid Foramen—Foramen mastoideum (NAV); Post-Mastoid Foramen (Gregory 1910); Postmastoid Foramen (McDowell 1958) Mastoideohyoideus Muscle—(Thiel 1955); Musculus mastoideostyloideus (Saban 1968); Musculus jugulohyoideus (Evans 1993) Maxilla—Os maxillare (NAV); Maxillary (Gregory 1910) Maxillary Foramen—Foramen maxillare (NAV) Maxillary Nerve—Nervus maxillaris (NAV) Maxillary Process of Frontal—(Evans 1993) Maxillary Recess—Recessus maxillaris (NAV) Maxillary Vein—Vena maxillaris (NAV) Maxilloturbinate (= Ventral Nasal Concha)—Os conchae nasalis ventralis (NAV) Meckel’s Cartilage—(De Beer 1937) Medial Pterygoid Muscle—Musculus pterygoideus medialis (NAV) Medial Section of Caudal Tympanic Process of Petrosal—(MacPhee 1981) Mental Artery—Arteria mentalis (NAV) Mental Foramen—Foramen mentale (NAV) Mental Nerves—Nervi mentales (NAV) Mental Vein—Vena mentalis (NAV) Mesocranium—(Wible et al. 2004) Middle Cranial Fossa—Fossa cranii media (NAV) 1/6/09 9:25:45 AM 400 Annals of Carnegie Museum Vol. 77 Appendix 1., continued Middle Nasal Meatus—Meatus nasi medius (NAV) Middle Ear—Auris media (NAV) Middle Ear Ossicles—Ossicula auditus (NAV) Middle Meningeal Artery—Arteria meningea media (NAV) Minor Palatine Artery—Arteria palatina minor (NAV) Minor Palatine Foramen—(Wible and Rougier 2000); Foramen palatinum caudale (NAV); Postero-External Palatine Foramen (Gregory 1910); PosteriorPalatine Canal (McDowell 1958) Minor Palatine Nerve—Nervus palatinus minor (NAV) Molars—Dentes molares (NAV) Muscular Process of Malleus—Malleus, Processus muscularis (NAV) Muscular Process of Stapes—Processus muscularis stapedius (Henson 1961) Muscular Tubercle—Os occipitale, Pars basilaris, Tuberculum musculare (NAV) Mylohyoid Line—Linea mylohyoideus (NAV) Nasal—Os nasale (NAV) Nasal Cavity (= Nasal Fossae)—Cavum nasi (NAV) Nasal Fossa—(Evans 1993); Olfactory Recess (Moore 1981) Nasal Septum—Septum nasi osseum (NAV) Nasal Surface of Maxilla—Os maxillare, Facies nasalis (NAV) Nasal Vestibule—Vestibulum nasi (NAV) Nasolacrimal Canal—Canalis lacrimalis (NAV) Nasolacrimal Duct—Ductus nasolacrimalis (NAV) Nasopalatine Duct—(Asher 2001); Ductus incisivus (NAV) Nasopharyngeal Meatus—Meatus nasopharyngeus (NAV) Nasoturbinate, Ethmoid—(Smith and Rossie 2006); Concha nasalis dorsalis (NAV); Endoturbinalia I (Evans 1993) Nasoturbinate, Nasal—(Smith and Rossie 2006); Crista ethmoidalis (NAV) Neck of Malleus—Malleus, Collum mallei (NAV) Nerve of Ampulla of Posterior Semicircular Canal—(Terry 1942); Nervus ampullaris posterior (NAV) Nerve of Pterygoid Canal—Nervus canalis pterygoidei (NAV); Vidian Nerve (McDowell 1958) Nerves of Saccule—(Terry 1942); Nervus saccularis (NAV) Nerve of Utricle—(Terry 1942); Nervus utricularis (NAV) Notochord—(Evans 1993) Nuchal (= Lambdoid) Crest—Crista nuchae (NAV) Occipital Artery—Arteria occipitalis (NAV) Occipital Complex—(Wible 2003); Os occipitale (NAV) Occipital Condyle—Condylus occipitalis (NAV) Occipital Emissary Vein—Vena emissaria occipitalis (NAV) Occiput—(NAV) Oculomotor Nerve (= Cranial Nerve III)—Nervus oculomotorius (NAV) Odontoid Notch—(Wible 2003); Incisura intercondyloidea (Evans 1993) Olfactory Bulb—Bulbus olfactorius (NAV) Olfactory Nerve (= Cranial Nerve I)—Nervi olfactorii (NAV) Ophthalmic Artery—Arteria ophthalmica interna (NAV) Ophthalmic Nerve (= Cranial Nerve V1)—Nervus ophthalmica (NAV) Ophthalmic Vein—Vena ophthalmica interna (NAV) Optic Foramen—Canalis opticus (NAV) Optic Nerve (= Cranial Nerve II)—Nervus opticus (NAV) Oral Cavity—Cavum oris (NAV) Orbicular Apophysis of Malleus—(Henson 1961) Orbit—Orbita (NAV) Orbital Crest—Crista orbitalis (NAV) Orbital Lamina of Ethmoid—Os ethmoidale, Lamina orbitalis (NAV) Orbital Rim—Margo orbitale (NAV) Orbital Surface of Lacrimal—Os lacrimale, Facies orbitalis (NAV) Orbital Surface of Maxilla—Os maxillare, Facies orbitalis (NAV) Orbitosphenoid—Os presphenoidale, Ala orbitalis (NAV) Orbitotemporal Groove—(Rougier et al. 1992) Orbitotemporal Canal—(Rougier et al. 1992); Sinus Canal (Gregory Wible.indd 400 1910; McDowell 1958) Orbitotemporal Crest—Crista orbitotemporalis (NAV) Orbitotemporal Fossa—Orbita + Fossa temporalis (NAV) Orifice of Canal for Modiolus—(Terry 1942) Os Proboscidis—(Brandt 1833) Osseous Lamina of Mallei—(Evans, 1993); Lamina (Henson 1961) Osseous Nasal Septum—Septum nasi osseum (NAV) Outer Lamella of Malleus—(Henson 1961) Oval Window—Fenestra vestibuli (NAV) Palatine—Os palatinum (NAV) Palatine Canal—Canalis palatinus (NAV) Palatine Process of Maxilla—Os maxillare, Processus palatinus (NAV) Palatine Process of Premaxilla—Os incisivum, Processus palatinus (NAV) Palatine Surface of Maxilla—Os maxillare, Facies palatina (NAV) Palatine Surface of Palatine—Os palatinum, Facies palatina (NAV) Palatine Surface of Premaxilla—Os incisivum, Facies palatina (NAV) Palatolacrimal suture—Sutura palatolacrimalis (NAV) Palatomaxillary Suture—Sutura palatomaxillaris (Evans, 1993); Sutura palatina transversa (NAV) Paracondylar Process of Exoccipital—Processus paracondylaris (NAV); Paroccipital Process of Exoccipital (Gregory 1910) Paraflocculus of Cerebellum—Paraflocculus (NAV) Parietal—Os parietale (NAV) Parietal Foramen—(Boyd 1930, 1934) Parietosquamosal Suture—Sutura squamosa (NAV) Paroccipital Process of Petrosal—(Wible and Gaudin 2004); Mastoid Process (Gregory 1910); Mastoid Eminence (MacPhee 1981) Pars Canalicularis of Petrosal—(Wible 1990; Wible et al. 1995, 2001) Pars Cochlearis of Petrosal—(Wible 1990; Wible et al. 1995, 2001) Pars Glandularis of Hypophysis—(Evans 1993); Adenohypophysis (NAV) Pars Orbitalis of Frontal—Os frontale, Pars orbitalis (NAV) Pars Processus Anterioris of Malleus*—(Henson 1961) Pedicle of Incus—(Henson 1961) Peduncle of Condylar Process of Mandible*—(Luo et al. 2002) Perbullar Canal for Internal Carotid Artery*—(Wible, 1986) Perilymphatic Duct—Ductus perilymphaticus (NAV) Perilymphatic Vein—Vein of Cochlear Canaliculus (Patten 1942) Permanent Teeth—Dentes permanentes (NAV) Perpendicular Plate (Lamina) of Ethmoid—Os ethmoidale, Lamina perpendicularis (NAV) Perpendicular Process of Palatine—Os palatinum, Lamina perpendicularis (NAV) Petrobasilar Fissue—(Evans 1993); Fissura petrooccipitalis (NAV) Petrosal (= Petrous Temporal)—Os temporale, Pars petrosa (NAV) Petrosal Process of Rostral Process of Malleus—this study Petrosquamous Suture—Sutura squamosomastoidea (NAV) Petrotympanic Fissure*—(Evans 1993); Fissure petrotympanica (NAV) Piriform Fenestra—(MacPhee 1981); Foramen Lacerum Medium (Gregory 1910); Pyriform Fenestra (McDowell 1958) Posterior Clinoid Process*—(Gregory 1910); Os basisphenoidalis, Processus clinoideus caudalis (NAV) Posterior Continuation of Crista Parotica—(MacPhee 1981); Lateral Section of Caudal Tympanic Process of Petrosal (MacPhee 1981) Posterior Crus of Ectotympanic—Annulus tympanicus, Crus posterior (NAV) Posterior Crus of Stapes—Stapes, Crus caudale (NAV) Posterior Digastric Muscle—Musculus digastricus, Venter caudalis (NAV) Posterior Division of Ramus Superior of Stapedial Artery—(Wible and Gaudin 2004) Posterior Ligament of Incus—Ligamentus incudis posterius (NAV) Posterior Nasal Spine—Spina nasalis caudalis (NAV) Posterior Opening of Posttemporal Canal—(Wible and Gaudin 2004); Posttemporal Foramen (Wible 2003) 1/6/09 9:25:45 AM 2008 Wible—On the Cranial Osteology of Solenodon paradoxus 401 Appendix 1., continued Posterior Semicircular Canal—Canalis semicircularis posterior (NAV) Posterodorsal Ethmoidal Foramen—this study Posterodorsal Process of Premaxilla—(Wible et al. in press) Postglenoid Area of Squamosal—this study Postglenoid Foramen—Foramen retroarticulare (NAV); Post-Glenoid Foramen (Gregory 1910) Postglenoid Process*—Processus retroarticulare (NAV) Postglenoid Vein—Vena emissaria foraminis retroarticularis (NAV) Postorbital Process*—Os frontale, Processus zygomaticus (NAV) Postpalatine Torus—(McDowell 1958); Crista palatina (NAV) Posttemporal Canal—(Rougier et al., 1992); Percranial Canal (MacPhee 1994) Posttemporal Foramen (= Posterior Opening of Posttemporal Canal) (Wible and Gaudin 2004) Posttemporal Sulcus—Posttemporal Groove (Wible et al. 2001); Sulcus for Diploic Vessels (Wible 1990) Posttympanic Crest of Squamosal—(Wible et al. 2004) Posttympanic Process of Squamosal—(Kielan-Jaworwoska 1981; Novacek 1986); Processus retrotympanicus (NAV); Post-Tympanic Process of Squamosal (Gregory 1910) Prefacial (= Suprafacial) Commissure—(De Beer 1937) Preglenoid Area of Squamosal—this study Premaxilla—Os incisivum (NAV); Premaxillary (Gregory 1910) Premolars—Dentes praemolares (NAV) Presphenoid—Os presphenoidale, Corpus (NAV) Presphenoid-Basisphenoid Synchondrosis—Synchondrosis intersphe noidalis (NAV) Presphenoid Wing—this study Primary Lamina of Ethmoturbinal I and II—(Smith and Rossie 2006) Process for Digastric Muscle of Mandible—this study Processus alaris, Ala temporalis—(De Beer 1937) Promontorium of Petrosal—(Evans, 1993) Prootic Canal—(Wible 1990; Wible and Hopson 1995; Rougier and Wible 2006) Prootic Sinus—(Wible 1990; Wible and Hopson 1995; Rougier and Wible 2006) Pterygoid Canal—Canalis pterygoideus (NAV) Pterygoid Hamulus—Hamulus pterygoideus (NAV); Hamular Process (McDowell 1958) Pterygoid Veins—Venae pterygoideae (NAV) Pterygopalatine Fossa—Fossa pterygopalatina (NAV) Pterygopalatine Suture—Sutura pterygopalatina (NAV) Ramus Inferior of Stapedial Artery—(Wible 1987) Ramus Infraorbitalis—(Wible, 1987); Arteria maxillaries (NAV) Ramus of Mandible—Ramus mandibulae (NAV) Ramus Mandibularis—(Wible, 1987) Ramus Posterior of Stapedial Artery—(MacPhee 1981) Ramus Superior of Stapedial Artery—(Wible 1987) Ramus Supraorbitalis—(Wible, 1987) Ramus Temporalis of Stapedial Artery—(Wible, 1987) Recessus Frontalis of Pars Intermedia of Nasal Capsule—(Smith and Rossie 2006); Posterior Superior Recess (McDowell 1958) Recessus Lateralis of Pars Intermedia of Nasal Capsule—(Smith and Rossie 2006); includes Recessus Maxillaris and Recessus Frontalis Recessus Maxillaris of Pars Intermedia of Nasal Capsule—(Smith and Rossie 2006); (NAV) Recessus Meatus—(Klaauw 1931; McDowell 1958) Rectus Capitis Lateralis Muscle—Musculus rectus capitis lateralis (NAV) Rectus Capitis Ventralis Muscle—Musculus rectus capitis ventralis (NAV) Retromolar Space—Retromolar Fossa (Hiatt and Gartner 1987) Rostral Alar Foramen*—Foramen alare rostrale (NAV) Rostral Cranial Fossa—Fossa cranii rostralia (NAV) Rostral Opening of Pterygoid Canal—(Wible and Gaudin 2004) Rostral (= Anterior) Process of Malleus—Malleus, Processus rostralis Wible.indd 401 (NAV); Folian Process of Malleus (McDowell 1958); Tympanic Plate of Anterior Process of Malleus (Henson 1961) Rostral Septal Branch of Major Palatine Artery—Rami septi rostrales (Evans, 1993) Rostral Tympanic Process of Petrosal—(MacPhee 1981) Rostrum—(NAV) Root of Teeth—Dentes, Radix dentis (NAV) Round window—Fenestra cochleae (NAV) Saccule—Sacculus (NAV) Sagittal Crest—Crista sagittalis externa (NAV) Sagittal Part of Vomer—(Evans 1993) Secondary Facial Foramen—(Wible 1990; Wible and Hopson 1993) Secondary Tympanic Membrane—Membrana tympani secundaria (NAV) Semicircular Canal—Canalis semicircularis (NAV) Septal Branch of Caudal Nasal Nerve (= Nasopalatine Nerve)—(Evans, 1993); Nervus nasopalatinus (NAV) Septal Process of Maxilla—(this study) Septal Process of Nasal—Os nasale, Processus septalis (NAV) Septal Process of Premaxilla—(this study) Septum Frontomaxillare—(Smith and Rossie 2006) Sigmoid Sinus—Sinus sigmoideus (NAV) Shoulder of Anterior Crus of Stapes—(Henson 1961) Shoulder of Posterior Crus of Stapes—(Henson 1961) Sphenoethmoidal Suture—Sutura sphenoethmoidalis (NAV) Sphenoid Complex—(Wible 2003) Sphenoidal Fossa—(Evans 1993) Spheno-occipital Synchondrosis—Synchondrosis spheno-occipitalis (NAV) Sphenopalatine Artery—Arteria sphenopalatina (NAV) Sphenopalatine Foramen—Foramen sphenopalatinum (NAV) Sphenopalatine Vein—Vena sphenopalatina (NAV) Sphenoparietal Emissary Vein—Vena spheno-parietalis (Gelderen 1924) Sphenorbital Fissure—(Gregory 1910; Novacek 1986); Fissura orbitalis + Foramen Rotundum + Foramen alare rostrale + Foramen alare parvum (NAV); Orbital Fissure (Evans 1993) Spiral Cribriform Tract—Tractus spiralis foraminosus (NAV) Spiral Ganglion—(Terry 1942); Ganglion spirale cochleae (NAV) Squama frontalis—(NAV) Squama of Squamosal—(Wible 2003) Squamosal—Os temporale, pars squamosa (NAV) Stapedial Artery—Arteria stapedia (Tandler 1899, 1902; Wible 1984, 1987) Stapedial Foramen—Intercrural Foramen; Obturator Foramen (Henson 1961); Intracrural Foramen (Wible 2003) Stapedius Fossa—(Wible 1990); Fossa for Musculus Stapedius (Evans 1993) Stapedius Muscle—Musculus stapedius (NAV) Stapes—(NAV) Sternomastoid Muscle—(Allen 1910); Musculus sternomastoideus (Evans 1993) Styliform Process of Ectotympanic—(Klaauw 1931); Anteromesial Spine of Ectotympanic (McDowell 1958); Anterior Process of Ectotympanic (MacPhee 1981); Os temporale, Pars tympanica, Processus muscularis (NAV) Stylohyal—Stylohyoideum (NAV) Stylohyal Facet on Tympanohyal—this study Stylomastoid Artery—Arteria sylomastoidea (NAV) Stylomastoid Foramen* —Foramen stylomastoideum (NAV) Stylomastoid Notch—Foramen stylomastoideum (NAV) Subarcuate Fossa—Fossa subarcuata (NAV); Floccular Fossa (Gregory 1910) Submandibular Gland—Glandula submandibularis (NAV); Submaxillary Gland (Allen 1910) Suboptic Foramen—(Gregory 1910) Sulcus for Inferior Petrosal Sinus—Sulcus sinus petrosa ventralis (NAV) 1/6/09 9:25:45 AM 402 Annals of Carnegie Museum Vol. 77 Appendix 1., continued Sulcus for Occipital Emissary Vein—New term Sulcus for Prootic Sinus—(Wible 1990) Sulcus for Sigmoid Sinus—(Wible 1990) Sulcus septi nasi—(Evans, 1993); Sulcus vomeris (septalis) (NAV) Sulcus tympanicus—(NAV) Superior Articular Facet of Malleus—(Henson 1961) Superior Articular Surface of Incus—(Henson 1961) Superior Vestibular Area—(Terry 1942); Area vestibularis superior (NAV) Suprameatal Crest—Dorsal Boundary of External Acoustic Meatus (Evans 1993) Suprameatal Foramen—(Novacek 1986); Subsquamosal Foramen (Gregory 1910) Supraoccipital—Os occipitalis, Squama occipitalis (NAV) Supraoccipital Crest—this study Supraoccipital Foramina—(Wible et al. 2004) Supra-Optic Foramen—(Gregory 1910) Symphyseal Surface of Mandible—(Evans 1993) Tectorial Lamina of Ethmoid—Os ethmoidale, Lamina tectoria (NAV) Tectum nasi—(Zeller 1987) Tegmen Tympani—(De Beer 1937; Moore 1981); (NAV) Temporal Fossa—Fossa temporalis (NAV) Temporal Line—Linea temporalis (NAV) Temporal Region—Regio temporalis (NAV) Temporal Sinus*—(Evans 1993); Sinus temporalis (NAV); Capsuloparietal Emissary Vein (Gelderen 1924) Temporalis Muscle—M. temporalis (NAV) Tensor Tympani Muscle—Musculus tensor tympani (NAV) Tentorium Cerebelli—Tentorium cerebelli membranaceum (NAV) Thyrohyal—Thyrohyoideum (NAV) Thyroid Cartilage—Cartilago thryroidea (NAV) Thyroid Foramen—Foramen thyroideum (NAV) Tracheal Rings—Cartilagines tracheales (NAV) Transverse Canal of Basisphenoid—(Gregory 1910) Transverse Canal of Presphenoid—(Gregory 1910) Transverse Canal Foramen—(Sánchez-Villagra and Wible 2002); Transverse Canal (Gregory 1910); Foramen Vesalii (McDowell 1958) Transverse Crest of Petrosal—Crista transversa (NAV) Transverse Lamina—(Smith and Rossie 2006) Transverse Sinus—Sinus transversus (NAV) Transverse Sinus of Basisphenoid—(Gregory 1910) Transverse Sinus of Presphenoid—(Gregory 1910) Trigeminal Ganglion—Ganglion trigeminale (NAV); Gasserian or Semilunar Ganglion (McDowell 1958) Trigeminal Ganglion Fossa—Gasserian Fossa (McDowell 1958); Trigeminal Fossa (Wible 1990); Semilunar Recess (Rougier et al. 1992) Trigeminal Nerve (= Cranial Nerve V)—Nervus trigeminus (NAV) Trochlear Nerve (= Cranial Nerve IV)—Nervus trochlearis (NAV) Tympanic (= Middle Ear) Cavity—Cavum tympani (NAV) Tympanic Canaliculus—Canaliculus tympanicus (NAV) Tympanic Incisure—(Henson 1961) Tympanic Nerve—Nervus tympanicus (NAV) Tympanic Process of Alisphenoid—(MacPhee 1981); Tympanic Crest of Alisphenoid (Gregory 1910); Preotic Crest of Alisphenoid (McDowell 1958) Tympanohyal—Tympanohyoideum (NAV) Tympano-Occipital Fissure *—(Evans 1993); Fissura tympanooccipitalis (NAV) Tympanum—(NAV) Vena diploëtica magna—(Hyrtl 1853, 1854) Ventral Condyloid Foramina—(Wible and Gaudin 2004) Ventral Condyloid Fossa—Fossa condylaris ventralis (NAV) Ventral Nasal Concha (= Maxilloturbinate)—Os conchae nasalis ventralis (NAV) Ventral Nasal Meatus—Meatus nasi ventralis (NAV) Vermis of Cerebellum—Vermis (NAV) Vertical Part of Exoccipital—(Wible 2003) Vestibular Aqueduct—Apertura externa aqueductus vestibuli (NAV); Opening for Vestibular Aqueduct (Evans 1993) Vestibular Fossula—(MacPhee 1981) Vomer—(NAV) Vomeronasal Organ—Organum vomeronasale (NAV) Vomeropalatine Suture—Sutura vomeropalatina dorsalis (NAV) Wings of Vomer—Alae vomeris (NAV) Yoke—Jugum sphenoidale (NAV) Zygoma*—Arcus zygomaticus (NAV) Zygomatic Process of Lacrimal—(Wible 2003) Zygomatic Process of Maxilla—Os maxillare, Processus zygomaticus (NAV) Zygomatic Process of Squamosal—Os temporale, Pars squama, Processus zygomaticus (NAV) Zygomaticus Minor— (Whidden 2002); Musculus zygomaticus (NAV) Utricle—Utriculus (NAV) Vagus Nerve (= Cranial Nerve X)—Nervus vagus (NAV) Vascular Foramen of Lacrimal—(Giannini et al. 2006) Wible.indd 402 1/6/09 9:25:45 AM