Lizards of the genus Xenosaurus are viviparous dwellers of crevices and holes and they range throughout much of central and southern Mexico and into Guatemala (Ballinger et al.
Given that some species and populations of Xenosaurus are classified as endangered or threatened by the Mexican government (e.
Not all species and populations of Xenosaurus are sexually dimorphic in size (e.
This contrasts with most other studies of Xenosaurus, which have reported that males had larger heads and often larger femurs (e.
The knob-scaled lizard, Xenosaurus grandis is distributed as disjunct populations from west central Veracruz southward to Guerrero, Oaxaca and Chiapas, Mexico to Alta Verapaz, Guatemala (Ballinger et al.
The following Xenosaurus grandis specimens from Veracruz, Mexico were examined: LACM 5927, 10981,75420, 75688, 75690, 75691, 75694, 104942, 120049-120057, 120059, 120060, 120064, 120065, 120070, 120071, 120075-120077, 120080-120084, 120086, 120087, 121537, 135539, 135541, 135544, 135545, 135547, 136334-136336.
Monthly stages in testicular cycle of 11 Xenosaurus grandis from Veracruz, Mexico.
The few Xenosaurus
species from Mexico, on the contrary, exhibit a very regular Squamata supraocular pattern with some Pleurodontid reminiscences, affording complete, evident circumorbital semicircles, opposed to moderate supraciliaries and, within their boundaries, a longitudinal row of broader scales, 4-5 in number, having some rows of irregular smaller scales on both sides.
tuxtlae Werler y Shannon 1893 Pr E Xenosauridae Xenosaurus
grandis (Gray 1856) Pr N X X X SERPENTES Boidae Boa constrictor (Linnaeus 1758) A, CI N X Colubridae Adelphicos quadrivirgatus Jan 1862 Pr N X X Amastridium veliferum Cope 1861 N Chersodromus liebmanni Reinhartd 1860 Pr E Coniophanes bipuncatus (Gunther 1858) N C.