Cophosaurus texanusGreater Earless Lizard

Geographic Range

This species is found just west of Fort Worth and Austin to the eastern Trans-Pecos area in Texas and into Arizona and Northern Mexico. C. texanus is absent from the eastern part of Texas, the Lower Rio Grande Valley and the Panhandle (Bartlett and Bartlett 1999).

Habitat

Cophosaurus texanus texanus is a terrestrial lizard which inhabits rocky areas such as desert flats, streambeds and limestone cliffs (Barker and Garrett 1987). Juveniles use rock perches more frequently than adults .

Physical Description

This lizard ranges from about 2 and 3/4 to 7 and 1/4 inches from snout to tip of the tail (Barker and Garrett 1987). However, females are smaller than males. Skin coloration depends on habitat but the dorsal ground color is usually from gray to brown to reddish with head, tail, body and legs sprinkled with small light spots. The tail is mostly black underneath with dark bars on top and on the limbs of the animal. The male and female are sexually dimorphic: the male has two distinct black lines in a field of blue and yellow, anterior to the hind legs that wrap onto the venter and stop abruptly. The females and juveniles of the species have a distinct dark stripe on the back side of each thigh, surrounded by a lighter color. Pregnant females take on a pink coloration on their flanks. In both sexes, the tail and body are slightly flattened and no external ear openings are present (hence, their common name) (Bockstanz and Cannatella 1998). C. texanus has two throat folds, fairly large eyes and twenty-seven or fewer feomoral pores. They are also characterized as having shorter forelegs than hind legs and fairly long toes (Barker and Garrett 1987).

Reproduction

The eggs of C. texanus are laid from March to August and take about fifty days to hatch (Bartlett and Bartlett 1999). Some evidence suggests that these lizards may lay three clutches in a season (Howland 1992). The young are precocial and are about two inches long at hatching. The Texas earless lizard rarely reaches two years of age in the Central Texas area (Howland 1992).

Behavior

This diurnal species has the rare trait of being extremely active at all times of day, even during the hottest hours (Bartlett and Bartlett 1999). In fact, the only time it seems to hide is during cloudy days when it remains lethargic. C. texanus is speedy, and as it runs, the lizard raises its tail. It may wave the tail from side to side when slowing to a halt or when it's about to run (Bockstanz and Cannatella 1998). However, it rarely stops on flat, open ground, preferring rocks and boulders. It uses the rocks for protection by using its coloration to blend in when it feels threatened. C. texanus is not a very wary lizard and will stay still for quite a while before running from an approaching observer (Bulova 1994). Occasional heavy floods considerably devastate populations of Cophosaurus.

Food Habits

The Texas earless lizard is an insectivore, eating both adult and larval forms of insects such as beetles and grasshoppers (Barker and Garrett 1987). Juvenile earless lizards consume smaller prey items than do adults. This may be attributed to the inability of juveniles to handle large prey items.

Conservation Status

Other Comments

This species has also been called Holbrookia texana.

Contributors

Emily Rosenblum (author), Southwestern University, Stephanie Fabritius (editor), Southwestern University.

Glossary

Nearctic

living in the Nearctic biogeographic province, the northern part of the New World. This includes Greenland, the Canadian Arctic islands, and all of the North American as far south as the highlands of central Mexico.

World Map

desert or dunes

in deserts low (less than 30 cm per year) and unpredictable rainfall results in landscapes dominated by plants and animals adapted to aridity. Vegetation is typically sparse, though spectacular blooms may occur following rain. Deserts can be cold or warm and daily temperates typically fluctuate. In dune areas vegetation is also sparse and conditions are dry. This is because sand does not hold water well so little is available to plants. In dunes near seas and oceans this is compounded by the influence of salt in the air and soil. Salt limits the ability of plants to take up water through their roots.

native range

the area in which the animal is naturally found, the region in which it is endemic.

References

Barker, D., J. Garrett. 1987. A Field Guide to Reptiles & Amphibians of Texas. Austin: Texas Monthly Press.

Bartlett, P., R. Bartlett. 1999. A Field Guide to Texas Reptiles & Amphibians. Houston: Gulf Publishing Company.

Bockstanz, L., D. Cannatella. 1998. "Herps of Texas" (On-line). Accessed (Date Unknown) at http://www.zo.utexas.edu/research/txherps/.

Bulova, S. 1994. Ecological correlates of population and individual variation in antipredator behavior of two species of desert lizards. Copeia, 4: 980-992.

Howland, J. 1992. Life history of Cophosaurus texanus: environmental correlates and interpopulational variation. Copeia: 82-93.