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Anura Caudata Gymnophiona Gymnophiona Anura Caudata Gymnophiona Caudata Anura Relationships of the amphibian clades Morphology (e.g., Milner 1988) Molecular evidence shakes up the amphibian tree Hay et al. 1995 • 1995 • One mtDNA gene – 850 bp • • 28 of 40 Families sampled Parsimony and distance analyses Feller and Hedges 1998 • • 1998 Four mtDNA genes – 2700 bp • Parsimony, distance (neighbor joiningj), and Bayesian analyses • Full mitochondrial genomes – (~15000 bp) • Parsimony, distance (nj), and Bayesian analyses 2005 522 species 2400 bp mtDNA 2300 bp nDNA 156 morph characters Anura Caudata Gymnophiona Parsimony analysis 3 genes mtDNA 9 genes nDNA likelihood Caudata: node-based name for salamanders Urodela: stem-based name for salamanders 10 families, 695 species Salamander characteristics • Tailed, most with four limbs of approximately equal length, four digits on front limbs, five digits on hindlimbs • Aquatic, terrestrial/fossorial, arboreal • Breathe through lungs, gills, and/or skin • Sprawling gait • Large genome – 15-90 pg (humans: 3pg) • Diverse life cycles, reproductive modes • Skull: absence of postorbital, supratemporal, jugal, supraoccipital, basioccipital, ectopterygoid • Limb regeneration •Loss of limbs •Tail reduced •Cylindrical body •Sprawling gait •Long tail •Hindlimbs = forelimbs •Upright posture •Loss of tail •Hindlimbs > forelimbs •Sprawling gait •Long tail •Hindlimbs = forelimbs digimorph Salamander reproduction • Internal (spermatophore) or external fertilization • Most oviparous • Most breed, lay eggs in water • Most have larval stage (tadpole) • Few have parental care • Complex courtship, pheromones spermatophore Courtship in Ambystoma talpoideum Mating behavior... Salamander diversity Variable characters within Caudata • External/internal fertilization (w spermatophore) • Costal grooves • Ribs unicapitate/bicapitate • Paedomorphic characters – Gills – Absence of eyelids – Tailfin, webbed feet • Chromosome number, amount of DNA Sirenidae • two genera, 4 species • SE USA • elongate, paedomorphic external gills, lack eyelids • nonpedicellate teeth • lack pelvic girdle, hindimbs • aquatic • external fertilization Sirenidae • two genera, 4 species • SE USA • elongate, paedomorphic external gills, lack eyelids • nonpedicellate teeth • lack pelvic girdle, hindimbs • aquatic • external fertilization Cryptobranchidae • Andrias (2 sp: China, Japan), Cryptobranchus alleganiensis (E USA) • paedomorphic lidless eyes, (internal) gills, absence of tongue pad • aquatic • largest amphibians (1.8 m) • external fertilization Cryptobranchidae Amphiumidae • • • • • • • • one genus, 3 species SE USA elongate, paedomorphic: lack eyelids, tongue; have (internal) gills retain both pairs of limbs (and girdles), but small limbs aquatic up to 1.1 m long internal fertilization female parental care Two-toed amphiuma Amphiuma means Ambystomatidae • One genus, 32 species • North America • some paedomorphic • hybrids, unisexual forms • most terrestrial as adults, some aquatic Dicamptodontidae • • • • • one genus, four species NW USA large, up to 17 cm SVL eats terrestrial vertebrates facultative metamorphosis Proteidae • two genera, six species • Italy, Slovenia, Croatia, Eastern USA • aquatic • paedomorphic, external gills, tail fin Plethodontidae • • • • • 27 genera, 458 species Americas, Italy, S Korea nasolabial groove lack lungs diverse – Fossorial, terrestrial, aquatic, arboreal – Webbed feet, ballistic tongue, prehensile tail • well-studied for speciation Plethodontidae • • • • • 27 genera, 433 species Americas, Italy, S Korea Nasolabial groove lack lungs diverse – Fossorial, terrestrial, aquatic, arboreal – Webbed feet, ballistic tongue, prehensile tail • well-studied for speciation Plethodontidae Salamandridae • 21 genera, 115 spp • N America, Europe, Asia, N Africa • Newts • poisonous skin, aposematic coloration • some with terrestrial eft stage Rhyacotritonidae • • • • One genus, four species Pacific NW USA old growth coniferous forests internal fertilization Hynobiidae • • • • Nine genera, 43 species Asia external fertilization lungs reduced to absent Caudata phylogeny • Duellman & Trueb (1986) – Parsimony, 30 morph characters • Larson and Dimmick (1993) – 29 morph characters, 177 nDNA, parsimony • Gao and Shubin (2001) – 60 morph characters, 177 nDNA, parsimony; incl. fossil taxa • Weisrock et al. (2005) – mtDNA, nDNA (~1300 chars); parsimony, ML, Bayesian • Wiens et al. (2005) – Morph chars (~300), nDNA, mtDNA; parsimony, ML, Bayesian • Frost et al. (2006), Pyron and Wiens (2011) Pyron and Wiens 2011 Anura (Salientia): Frogs Anura (Salientia): Frogs 6728 species Synapomorphies of Anura • • • • • • urostyle lack tail fused tibia and fibula fused ulna and radius hindlimbs > forelimbs Nine (or fewer) presacral vertebrae
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