Crotaphytidae

The Crotaphytidae, or collared lizards, are a family  of desert-dwelling reptiles native to the Southwestern United States and northern Mexico. Alternatively they are recognized as a subfamily, Crotaphytinae, within the clade Pleurodonta. They are very fast-moving animals, with long limbs and tails; some species are capable of achieving bipedal running at top speed. This species is carnivorous, feeding mainly on insects and smaller lizards. The two genera contain 12 species.

They may be related to the extinct Arretosauridae of Paleogene Asia due to similar jaw morphologies, though other studies classify the Arretosauridae in Acrodonta with other Old World iguanians.

Technical characters

 * Femoral pores present
 * Interparietal scale small (distinctly smaller than ear opening)
 * Never have an enlarged middorsal scale row or fringe
 * Never have a divided rostral scale
 * No bony spines or projecting ridges on their heads
 * No scales projecting over their ears, and no scales forming a prominent fringe on sides of toes as in Phrynosomatidae

Species
Nota bene: A binomial authority in parentheses indicates that the species was originally described in different genus.