Ecology of Xenosaurus fractus (Squamata: Xenosauridae) from Sierra Nororiental, Puebla, Mexico

Abstract: Lizards in the genus Xenosaurus are crevice-dwelling lizards. Their crevice-dwelling habit may constrain their ecology; thus one might predict there could be limited variation in several ecological traits among species. Here we report on aspects of the ecology of the recently described Xenosaurus fractus from the Sierra Nororiental of Puebla, Mexico and compare it to other species of Xenosaurus. Mean body temperature of X. fractus was 19.67°C. Body temperature was related to air temperature and substrate temperature. We found no difference in thermal ecology between males and females. Crevice use was not related to the individual's body size, nor did male and females differ in crevice use. Crevice characteristics had limited effects on body temperature. Sexual size dimorphism was not present in body size or head size, except for dimorphism in the relative growth of head width with snout-vent length. Xenosaurus fractus ate mostly insects, with caterpillars the most important prey. In conclusion, the ecology of X. fractus is similar to other species of Xenosaurus in many ways. Of particular interest is the observation that X. fractus does not appear to be any more similar to its sister species X. tzacualtepantecus than it is to other species of Xenosaurus.