Xantusiidae is a clade of viviparous (live bearing) lizards that
ranges from southwestern North America and Baja California
(Xantusia) into Central America (Lepidophyma) and Cuba
(Cricosaura). Xantusia magdalena occurs in Baja California.
Xantusiidae is a relatively small clade, with 3 genera and
approximately 30 living species. Lepidophyma is the most
speciose (~17 species), whereas Cricosaura is monotypic.
Xantusiids have a reasonably good fossil record extending from
the mid-Paleocene onward in western North America. Xantusiids
are fascinating lizards for several reasons. First, although
they are almost uniformly diminuitive (Xantusia magdalena
measures less than 4 cm snout-vent length, and the largest
xantusiid species measure about 10 cm snout-vent length),
xantusiids generally take several years to reach sexual
maturity, and several species give birth to just 1 or 2
offspring. It is a more usual reproductive strategy for small
lizards to mature quickly and produce large numbers of
offspring, to increase