Evolution of fossoriality in microteiid lizards

Morphology is among the most important traits influencing the interaction of individual animals with their environments. Fossoriality reflects this functional association between morphology and the use of subterranean habitats and their associated environmental characteristics. Lizards in the families Gymnophthalmidae and Alopoglossidae are model organisms to examine the interplay between morphology and fossoriality because great morphological diversity exists among species, including varying degrees of body elongation and limb reduction, and they have a wide geographical distribution in the Neotropical region. We analysed the morphology of 101 microteiid species and created an index to evaluate their degree of fossoriality. From this index, we traced the evolution of fossoriality in these lizards and assessed its primary environmental correlates. We found that fossoriality evolved independently in several lineages, mainly associated with high temperature and low precipitation, characteristic of more arid and sandy environments.