| The family Xantusiidae contains about 20 species in three genera. They range from the southwestern USA to Panama, with a representative genus on Cuba. Their relationship to other groups of lizards is uncertain, however, a recent DNA study places them as the sister to the African Plated Lizards (Gerrhosauridae) and the Girdled-tailed Lizards (Cordylidae) (Vidal and Hedges, 2009. C. R. Biologies 332:129-139). They lack moveable eyelids and have granular dorsal scales. They have evolved a placenta-like structure that allows the female to provide the developing young with nutrients (this has also evolved in other groups of squamates), thus the females are all live bearing. At least one species is parthenogenetic (an all female species). As a group they are small, usually less that 50 mm in body length, but one species reaches a 100 mm; they tend to have elongated bodies, and small limbs. As a group they grow slowly and live long lives, with one species living at least 9 years. The common name is some what misleading, since many are diurnal. Many of these lizards are crevice dwellers, living under exfoliating rocks, layers of dead leaves, or in burrows. But, a few will climb into vegetation. They feed upon insects, with some species eating plant materials. |
