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Zebra-tailed Lizard — Part 3
Distribution.—Apparently restricted to southwestern Texas.
Distribution.—Southern Arizona and Mexico generally.
Dimensions.—-
Distribution.—Southern Arizona, New Mexico, southwestern Texas and northern Mexico. Dwells principally in rocky places.
Distribution.—Abundant in the Great Basin. It occurs as far north as Oregon and is common in the mountains of eastern California, Idaho, Nevada and Utah to an altitude of 8,000 feet; most abundant on the sage-covered plateaus. Southward it extends through the deserts, into northern Mexico.
Habits.—Unlike the vast majority of lizards, the Horned "Toads" are viviparous--producing living young and to the number of from six to a dozen. The young are born in the same fashion as the viviparous snakes. They are encased in a transparent envelope through which they soon break. They are at once active and fully able to care for themselves. At birth they possess rudimentary horns and do not exhibit the rough, spiny appearance of the parent. In an illustration accompanying this chapter the size of the newly born young may be compared to that of the parent.
Head small and flattened. Limbs very long; the hind leg applied forward reaches to or beyond the snout; tail flattened.
Abdomen white, with a bluish patch on each side; each blue area contains two, sometimes three, ink-black bands. Lower surfaces of the tail of male specimens white, with black bars; the female lacks these bold markings, or they are but little evident.
The colouration is much like that of the Texas Zebra-tailed Lizard, Holbrookia texana, but the present species may be easily told by the exposed ear drum--tympanum.
Several varieties have been recognised--gabbii (Cope) and ventralis (Hallowell), but their varietal characters are not striking enough to appeal to the student. It should be remembered that the ear drum at once separates this lizard from all the species of Holbrookia.
Length of Tail . . . . . 2 1/2 inches.
Width of Body . . . . . 3/4 inches.
Width of Head . . . . . 7/16 inches.
Length of Head . . . . . 9/16 inches.
The Genus Uma: Four species have been named. All seem to be rare. The genus differs from Callisaurus in a peculiar development of the feet. Along the inner and outer margin of most of the toes, is a fringe of flat spines; this character is seemingly Nature's provision to aid these lizards in rapidly traversing the desert sands; to assist in this arrangement, the under portion of each claw is hollowed out--cup-like--and has sharp edges. The same development is found with some of Old World desert geckos. It is interesting to find such pronounced examples of adaptation, on exactly similar lines, in forms so far removed from one another both in classification and habitat. Similar conditions have been described under the head of the Horned Rattlesnake, Crotalus cerastes.
Following is a key to the species of Uma, embracing some of the definitions of Cope, who named three of these lizards.
I. Two black crescents on throat; a black spot on each side of abdomen.
Blackish, covered with pale and perfectly round blotches, the borders nearly touching; in the centre of each disk is a black spot. Abdomen white, with a black spot on each side. Two black crescents on throat, their points directed forward. Length about 8 inches; head and body, 4 inches.
ROUND-SPOTTED DESERT LIZARD, Uma scoparia, Cope.
II. No black crescents on throat; a black spot on each side of abdomen.
Brownish, with black, longitudinal lines; the brown between the dark bands often broken up into rounded blotches, each containing a reddish spot. A large, black spot on each side of the abdomen; throat with narrow, black, longitudinal lines. Length about 7 1/2 inches.
RED-SPOTTED DESERT LIZARD, Uma rufopunctata, Cope.
Colouration above, like U. scoparia. Abdomen white with a black spot on each side; chin and throat with a few blue or black spots.
OCCELLATED DESERT LIZARD, Uma notata, Baird.
III. No black spots on abdomen, or black crescents on throat. Greenish, with darker spots. No black spots on the the abdomen; seven black spots on under surface of tail.
COPE'S DESERT LIZARD, Uma inornata, Cope.
"This species was taken only in the drifting sand areas of the bed of the Mohave River, where it is a common form. It has the peculiar habit of burying itself in the sand when pursued. The peculiar fringe of scales along the toes evidently serves to give the lizard sufficient speed over the loose sand to force its body beneath the surface. The sharp, depressed snout is evidently another modification to aid in getting beneath the sand. Usually the entire body is buried, but occasionally the tip of the tail protrudes. Their peculiar, mottled colouration does not render them protectively coloured on the white sand, but their peculiar mode of eluding pursuers renders this unnecessary, and at the same time limits them to areas covered with fine, drifting sand.