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Mojave River Valley Museum
Mojave Fringe-toed LizardUma scoparia
Family: Phrynosomatidae Order: Squamata Class: Reptilia
DISTRIBUTION, ABUNDANCE, AND SEASONALITY
The Mojave fringe-toed lizard occurs in desert regions of Inyo, San Bernardino, Los
Angeles, and Riverside cos. Elevational range extends from near sea level up to
(3000 ft) (Stebbins 1985). It is restricted to fine, loose, wind-blown deposits in
(Heifetz 1941, Stebbins 1944, 1972, 1985, Norris 1958).
This is a lizard of sand dunes. You must be patient and observant to get a real good look, as these lizards run off with the first sign of hazard. The fringe toes act like snowshoes allowing them to run across the sand and escape enemies. Flaps over the ears, overlapping eyelids, and valves in the nostrils all protect the lizards from sand.
Mojave Fringe-toed Lizard Picture Gallery
The Mojave Fringe-toed Lizard (MFTL) is a medium-sized lizard (SVL 4.5 in [112 mm]) with a dorsoventrally compressed body and tail, small dorsal head and body scales, pointed snout in lateral profile, countersunk lower jaw, obliquely keeled supralabial scales, large eyelid fringe scales, large anterior auricular scales, large imbricate shoulder and upper arm scales, greatly enlarged lamellar fringes on third and fourth hind-toe, a tail equal to body length, and two large postanal scales in males, which are only slightly enlarged in females. The dorsal ground color is light brown to yellowish, with dark ocelli pattern on the body, limbs and tail. The ventral color is light yellow to white, with one to three dark crescents across the throat region, a dark ventrolateral body blotch between the fore- and hindlimbs, and dark caudal bars on the posterior portion of tail (Van Denburgh, 1922; Heifetz, 1941; Stebbins, 1944, 1985; Smith, 1946; Norris, 1958; Pickwell, 1972; de Queiroz, 1989).
The MFTL is distinguished from all other species of fringe-toed lizards by the presence of crescent-shaped markings on the throat, a nasal process of the premaxilla bone with the lateral crests reduced posteriorly, and a frontonasal fontanelle commonly present in the skull (Cope, 1895; Heifetz, 1941; Schmidt and Bogert, 1947; Norris, 1958; de Queiroz, 1989). It can be further distinguished from the Coachella Valley fringe-toed lizard (Uma inornata) by the presence of a dark ventrolateral body blotch between the fore- and hindlimbs, dorsal ocelli that never reticulate to form a lineate pattern, and usually five internasals instead of three (Heifetz, 1941; Smith, 1946; Norris, 1958).
The MFTL has numerous adaptations associated with its highly arenicolous (= sand-dwelling) life style (Cope 1894; Van Denburgh, 1922; Mosauer, 1932, 1935; Stebbins, 1944, 1972; Norris, 1958, 1967; Pough, 1970; Carothers, 1986; Luke, 1986). The most notable, of which, are the enlarged, triangular shaped lamellar fringes on the third and fourth digit of the hindfoot that enable these lizards to achieve considerable speeds on the sand surface (Stebbins, 1944; Norris, 1958; Carothers, 1986). Other adaptations associated with burying in the sand include a countersunk lower jaw, valved nostrils, keeled supralabials, enlarged and imbricate shoulder scales, and a dorsoventrally compressed body (Stebbins, 1944; Smith, 1946; Norris, 1958; Carothers, 1986). In addition, the dorsal network of dark ocelli on a yellowish ground color make these lizards extremely cryptic on the sandy substrate, while their more distinguishing characteristics are concealed ventrally on their throat, sides, and tail (Stebbins, 1944; Smith, 1946; Norris, 1958).
The MFTL is omnivorous, feeding on dried seeds, flowers, grasses, leaves, insects, and scorpions (Van Denburgh, 1922; Miller and Stebbins, 1964; Minnich and Shoemaker, 1970, 1972). It is likely that the food preference shifts seasonally as in the Coachella Valley fringe-toed lizard (Uma inornata) where more plant material is consumed in spring when it is available and arthropods later in the year (Durtsche 1992, 1995; see also, Minnich and Shoemaker, 1970). Juveniles eat more arthropods than plants (Minnich and Shoemaker, 1970). In captivity, species of Uma have been known to be aggressive towards other lizards and occasionally eat them (Shaw, 1950)