Added 9 August 2009.

A look at the

Genus Callisaurus - Zebra-Tailed Lizard

Family IGUANIDAE [PHRYNOSOMATIDAE]



Genus Callisaurus - Zebra-Tailed Lizard

There is but one species in the genus Callisaurus. Not all desert dwellers tolerate high temperatures, but this lizard certainly does, being found in open sandy areas with high daytime temperatures. Interestingly though, Bosch and Werning also record it as being found by the ocean in Baja California. The Zebra-Tailed Lizard is best known for its defence mechanism involving its black and white tail. When alarmed it coils the tail over its back and waves it to and fro, using it as a decoy. Mattison also suggested that the lizard's habit of keeping the tail upright when fleeing, and even poking it up in view of the frustrated predator, is a way of informing the latter that further chase is likely to be a waste of energy and that it might be better to quit. An alternative interpretation has been offered, that the moving upright black and white tail somehow distracts the predator.

Characteristics of the species are as follows: ear openings present; long, flat tail; black bars distinct on white undersurface of tail; slim, with long slender legs; supralabials separated by diagonal furrows; gular fold present; dorsal scalation granular. The ear opening easily allows it to be distinguished from the somewhat similar species Cophosaurus (Greater Earless Lizard) and Holbrookia (Lesser Earless Lizard). The taxonomy of the subspecies appears to be still not quite certain: see the Links section.

The speed of the lizard when running is quite remarkable, having been estimated at about 15mph. Their stopping and starting are both quite abrupt, and when stopping apparently skid to a halt for a few inches. When running they do not follow a straight line but describe an arc to the left or right, and if unable to find cover will run around in circles until tired when they will allow themselves to be picked up. See Smith for further anecdotal details. These are not social animals: Rogner states that in the wild they maintain individual territories.

Although not large, the species preys not only on insects and other arthropods, including small crustaceans, but on small lizards of the Uta genus. Their high metabolism means that they feed fairly often. This, the requirements for relatively large space and the need for high temperatures and strong UV radiation, makes them unsuitable for the casual keeper, and they are probably best left to iguanid or desert specialists. For care details, see Bosch and Werning, Rogner or Walls.

Scientific Name Common Name Distribution Size Notes
Callisaurus
C. draconoides Zebra-Tailed Lizard

S USA (California, Nevada, Arizona and New Mexico) and Mexico (Baja California, Sonora and Sinoloa) Max SVL 6¼-10cm/ 2½-4"; TL 23cm/9" See Introduction. Scalation details: 4-6 supraciliaries: large interparietal, which grades abruptly into the dorsal scales; undifferentiated frontonasals; 6-10 supralabials; 9-15 infralabials; single postmental. Dorsal scalation: granulars smooth, grading into smaller lateral scales and then large imbricate ventrals. Other: 29-50 subdigital lamellae on 4th toe. Coloration: variable, but usually overall whitish to dark grey; network of light spots may be present, but absent in dorsal region; series of paired paravertebral blotches usually present, running from neck to tail base; adults have yellow inguinal region and orange axillary region; grey gular region, with males having red centre; tails darkly banded, the bands being solid black below. See Lee for fuller details. Reproduction: males distinguished by 20-44 well developed femoral pores and 2 (sometimes 3-4) enlarged postanal scales. Up to 5 clutches of eggs laid, each clutch of 2-15 (more usually 1-8) eggs, in June-August. [SOURCES: Grismer, Stebbins, Smith]
C. d. draconoides Common Zebra-Tailed Lizard  USA, Mexico Max SVL 72mm (m), 67mm (f) Scalation details: lacks fringe of pointed scales on toes. Coloration: usually only 2 dark bars on abdomen, most clearly on male; posterior margins of dark paravertebral blotches are pointed; posterior blotches are connected medially, forming dark bands. See Grismer for fuller details: he also notes that much of the colour and pattern variation is due to substrate matching, and distinguishes different types for several populations from Baja California.
C. d. bogerti Bogert's Zebratail Lizard Mexico (Sinaloa)    No details yet available.
C. d. brevipes Short-Footed Zebratail Lizard Mexico (Sonora)    No details yet available. 
C. d. carmenensis Carmen Island Zebratail Lizard  Mexico (Carmen Island, Gulf of Mexico)  Max SVL 86mm (m), 68mm (f) This subspecies intergrades widely with the nominate subspecies. Coloration: differs from draconoides in the arrangement of the dorsal paravertebral spots (see Grismer for details).
C. d. crinitus Viscaino Zebratail Lizard Mexico (Baja California)  Max SVL 81mm (m), 69mm (f) This subspecies appears to be more orientated to life in the sand, since it apparently is more prone to bury itself in it and has fringes of scales on its toes which are most likely an adaptation to this habitat. It is only found in the Viscaino Desert. Scalation details: fringe of pointed scales on rear border of toes 2-4. Coloration: usually 3 dark bars on abdomen, most clearly on male, that are sometimes followed by a black spot; dense network of lighter spots; paravertebral blotches are faint to absent; postfemoral line not bordered in white.
C. d. inusitanus Sonoran Zebratail Lizard Mexico (Isla Tiburón in Gulf of California) Max SVL 109mm (m), 89mm (f) Coloration: adult males are laterally orangeish with longitudinal row of indistinct dark blotches and yellowish vertebral region; females have yellowish ventral patches; juveniles have lime-green tint to body; 2 dark ventral bars very faint and indistinct; turquoise belly patch.
C. d. myurus Nevada Zebratail Lizard     No details yet available: not mentioned by Stebbins.
C. d. rhodostictus Mojave Zebratail Lizard, Western Zebratail Lizard USA (S California), Mexico (Baja California) Max SVL 94mm (m), 83mm (f) This subspecies appears to be more orientated to life in the sand, since it apparently is more prone to bury itself in it and has fringes of scales on its toes which are most likely an adaptation to this habitat. It is only found in the Viscaino Desert. Scalation details: supraorbitals may be larger and more elongate than in other subspecies; moderately developed fringes may be present on toes 3-4, or poorly developed on toe 4. Coloration: usually 2 dark bars on abdomen, 2nd of which is wider, and not followed by a black spot; dense network of lighter spots; posterior margins of paravertebral blotches are rounded rather than pointed, and not connected medially; postfemoral line not bordered in white. Ground colour is variable, again largely due to substrate matching.
C. d. splendidus Angel Island Zebratail Lizard Isla Angel De La Guarda Max SVL 73mm Coloration: overall dorsally greyish to reddish-brown; dense network of light and dark spots; 2 distinct black ventral bars, very thin dorsally and wider in the middle than at the edges; some variation due to substrate matching (see Lee). 
C. d. ventralis Arizona Zebratail Lizard USA (California, Arizona, Nevada)   No details yet available: not mentioned by Stebbins.

Bibliography

Handbook of Lizards: Lizards of the United States and Canada, Hobart M Smith, Cornell University, 1946 (1995 reprint). Plenty of useful observations of the ecology of the Zebra-Tailed Lizard, although some of the subspecies taxonomy has since changed and C. d. gabbi is no longer accepted as a valid taxon.

A Field Guide to Reptiles and Amphibians of Eastern and Central North America, R Conant and J T Collins, Peterson Field Guides, Houghton Mifflin, Boston/New York 1998.

A Field Guide to Western Reptiles and Amphibians, R Stebbins, Peterson Field Guides, Houghton Mifflin, Boston/New York 2003. Stebbins does not mention the subspecies C. d. myurus and C. d. rhodostictus.

Green Iguanas and other Iguanids, Dr Hubert Bosch and Heiko Werning, TFH 1996 (originally published in German, 1991, as Leguane). See Iguanid page for recommendation of this book.

Amphibians and Reptiles of Baja California, Grismer, L Lee Grismer, University of California Press, 2002. Gives details on all the Baja Californian subspecies, which Grismer here calls "pattern classes".

Echsen [Lizards] 1, Rogner, Ullmer, 1992. German language publication, but an English translation is available.

"Going Native: Zebra-Tailed Lizard, Callisaurus draconoides, Blainville, 1835", Jerry G Walls, Reptile &Amphibian Hobbyist 6:6.


Links

JCVI/TIGR reptile database entry for Callisaurus draconoides.

CaliforniaHerps.com has an informative entry and several photographs of C. d. rhodostictus.

Tom Brennan has also got some good shots and a summary.

Wildherps.com has several photographs of both rhodostictus and ventralis.

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