Download Tympanocryptis lineata

Stefan Reissmann
TYMPANOCRYPTIS LINEATA = LINED EARLESS DRAGON
AD 2002-12-16
Tympanocryptis lineata
— A species account written by Stefan H. Reißmann in 2002 AD —
Authority: Peters, 1863
Common Name: Lined Earless Dragon
Systematics
(Cogger 1992, Greer 1989, Mitchell 1948, Storr 1964, Storr 1982):
Class :
Subclass :
Order :
Suborder :
Family :
Genus :
Species :
Reptilia
Lepidosauria
Squamata
Sauria
Agamidae
Tympanocryptis (Peters 1863)
Tympanocryptis lineata (Peters 1863)
Description
Fig. 1: The range of Tympanocryptis lineata including subspecies
which may constitute separate species.
(Cogger 1992, Greer 1989, Mitchell 1948, Storr 1964, Storr 1982):
As the genus name suggests, Tympanocryptis lineata lacks an external ear opening. The tympanum lies very deep to the skin. The
space in between is filled by the depressor mandibulae, and the stapes has become firmly connected with the quadrate. Another
characteristic trait, which characterizes the genus, is the loss of the fifth toe of the hind foot (phalangeal formula: 2.3.4.5.3.).
Tympanocryptis lineata is, like all members of its genus, a rather small and relatively stout terrestrial dragon, with a more or less
depressed body. Its snout-vent length reaches 22 to 72 mm, the tail is 1.2 to 2 times as long. The hind limbs are about 0.5 to
0.9 the as long as head and body together. The body mass is about 10g.
The head is longer than broad and has a gular fold and a fold of outstanding tubercles between the ankle of the mouth and the
shoulder. The scales on the top of the head and on the back are keeled. Dorsal, there are also scattered, enlarged sharply keeled
scales or spinose tubercles. T. lineata has no mid-dorsal crest, but it can raise the mid-dorsal skin into a distinct ridge. The gular
and ventral scales are either smooth or keeled. The nasal is separated from labial by four to six scales, the supralabiales have 11
to 16. The number of postsacral diapophyses is high, 24-37. T. lineata has been found to have 22-24 presacral and 45-50
postsacral vertebrae.
The body is greyish-brown to reddish brown above, with a pale grey vertebral stripe and to similar coloured longitudinal stripes
on each side, one dorso-lateral, the other one lateral. In addition, there are four or five dark transverse bars on each side of the
body, and 12 to 20 on the tail. The limbs exhibit also dark transverse bands. Ventral, T. lineata is whitish, sometimes flecked
with grey, brown or black. There are two light bands across the head, one between the supraciliary ridges, the other one across
the nape.
At least in some population there is a strong sexual dimorphism with adult females lacking the stripes and bars, which are so
conspicuous on males and juveniles.
Males usually have one preanal pore and occasionally one femoral pore on each side.
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Stefan Reissmann
TYMPANOCRYPTIS LINEATA = LINED EARLESS DRAGON
AD 2002-12-16
Subspecies & similar species
(Greer 1989, Mitchell 1948, Smith et al. 1999, Storr 1964, Storr 1982, Storr 1984):
Tympanocryptis lineata has about five subspecies. The status of some of them, however, is not clear. T. tetraporophora has once been
regarded as subspecies of T. lineata, and T.(l.) pinguicolla has been proposed to constitute a separate species. T. (l.) pinguicolla has
in contrast to T. l. lineata stumpy digits and foots and usually a axilla-groin fold.
Range
(Cogger 1992, Mitchell 1948, Smith et al. 1999, Storr 1964, Storr 1982):
Tympanocryptis lineata occurs from the Gulf of Carpentaria and the Joseph Bonaparte Gulf throughout the interior of Australia to
the great Australian Bight. It does not occur in Tasmania, the western two thirds of Western Australia, Arnhem Land, eastern
Queensland including Cape York Peninsula, and the parts of New South Wales and Victoria which lie east or south east of the
Great Dividing Range.
T. l. lineata lives in the southeastern part of the areal of the species. T. l. centralis occurs in the desert regions in the interior. T. l.
houstoni inhabits the Kimberleys and the northern Northern Territory. T. l. macra represents the species in the Nullarbor Plain.
And the range of T.(l.) pinguicolla extends through south-eastern New South Wales and north-western Victoria.
Habitat
(Cogger 1992, Greer 1989, Jenkins & Bartell 1980, Storr 1984, Swan 2001):
Tympanocryptis lineata inhabits a variety of open terrestrial habitats. Its distribution ranges from desert sand hills and grassland
through gibber and black soil plains to open woodland. Most of its habitats are characterized by packed or stony substrates. It
uses earth cracks, rock crevices, grass, ground litter and animal burrows for shelter.
Ecology & behaviour
(Cogger 1992, Greer 1989, Jenkins & Bartell 1980, Storr 1984, Warburg 1966):
Like most agamids, T. lineata is a heliotherm diurnal sit-and-wait predator. However, it has once been observed at night. It feeds
mainly on small arthropods. T. lineata is exclusively terrestrial, and its colour exhibits a close substrate matching. As other
members of the genus, T. lineata can control its colour, e.g. become brighter or darker, but it can apparently not change its local
colour pattern.
T. lineata and other species of the genus have been observed to sit upright on their hind limbs and tails for long periods, with
their front limbs held close to the body. The purpose of this behaviour is not clear. It could just serve for getting a better view
on the surroundings, or it may have a thermoregulatory function. The last hypothesis is supported by the fact, that a similar
behaviour has been observed under heat stress in the laboratory. The resistance of T. l. lineata to evaporative water loss is rather
low compared to other agamids of arid Australia. However, there may be a considerable interpopulation variation. T. (l.)
pinguicolla has been found to hibernate in depressions beneath rocks or in spider holes.
The audition of T. lineata is probably quite restricted, due to the morphological alteration of the ear. However, an individual of
T. lineata has been heard to give a high pitched squeak in confrontation with a dragon of another species.
A first response to predators is ‘freezing’, sitting absolutely emotionless. The last resort is to flee to a shelter site in the
vicinity. T. lineata does usually not run far.
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Stefan Reissmann
TYMPANOCRYPTIS LINEATA = LINED EARLESS DRAGON
AD 2002-12-16
Reproduction
(Greer 1989, Jenkins & Bartell 1980, Swan 2001):
Tympanocryptis lineata is oviparous. The clutch size is related to the female size. A female lays usually between nine and eleven
eggs. Problems in captivity suggest, that for egg deposition a so far unknown trigger or clue might be necessary. Moreover, egg
laying seems necessary for triggering the development of the embryo beyond a certain stage.
In central western Australia, females of T. lineata centralis have been found with eggs in late September. Thus, breeding can occur
in spring.
As already mentioned above, at least in some populations there is a strong sexual dimorphism in colouration. In those cases
females have usually a reduced stripe pattern compared to males; and in T. (l.) pinguicolla breeding males exhibit yellow throats
and pink pelvic regions.
References:
Cogger, H. G. 1992. Reptiles and Amphibians of Australia. Reed Books, Chatswood, NSW.
Greer, A. E. 1989. The Biology and Evolution of Australian Lizards. Surrey Beatty & Sons, Chipping Norton, NSW.
Jenkins, R. & Bartell, R. 1980. Reptiles of the Australian High Country. Inkata Press, Melbourne, Vic..
Mitchell, F. J. 1948. A revision of the lacertilian genus Tympanocryptis. Records of the South Australian Museum 9: 57-86.
Smith, W. J. S.; Osborne, W. S.; Donnellan, S. C.; Cooper, P. D. 1999. The systematic status of earless dragon lizards,
Tympanocryptis (Reptilia: Agamidae), in south-eastern Australia . Australian Journal of Zoology 47: 551-564
Storr, G. M. 1964. The agamid lizards of the genus Tympanocryptis in Western Australia . Journal of the Royal Society of Western
Australia 47: 43-50
Storr, G. M. 1982. Taxonomic notes on the genus Tympanocryptis Peters (Lacertilia: Agamidae). Records of the Western Australian
Museum 10(1): 61-66
Storr, G. M. 1984. Note on Tympanocryptis lineata macra (Lacertilia: Agamidae). Records of the Western Australian Museum 11(3):
317
Swan, G. 2001. A Photographic Guide to Snakes & Other Reptiles of Australia. New Holland Publishers, Sydney, NSW.
Warburg, M. R. 1966. On the water economy of several Australian geckos, agamids and skinks. Copeia 1966(2): 230-235
Remarks:
Unfortunately, the journal Herpetofauna (Sydney) has not been available to me. In relatively recent issues of it are a couple of
articles about Tympanocryptis lineata, particularly in the issues 23(1):pp.16-25 [1993] from Osborne et al., 26(1):p.44
[1996] from Bedford & O’Grady and 30(2):pp.22-24 [2000] from Swan.
Stefan H. Reissmann, 2002 AD
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