Brian Noonan and colleagues examined data from multiple gene regions to investigate the phylogeny of Xantusiidae using the most comprehensive taxonomic sampling available to date. Parsimony and partitioned Bayesian analyses of more than 7 kb of mitochondrial and nuclear sequence data from 11 loci confirm that Xantusiidae is monophyletic, and comprises three well-supported clades: Cricosaura, Xantusia, and Lepidophyma. The Cuban endemic Cricosaura typica is well supported as the sister to all other xantusiids. Estimates of divergence time indicate that Cricosaura diverged from the (Lepidophyma + Xantusia) clade 81 million years ago (Ma), a time frame consistent with the separation of the Antilles from North America. Their results also confirm and extend an earlier study suggesting that parthenogenesis has arisen at least twice within Lepidophyma without hybridization, that rock-crevice ecomorphs evolved numerous times within Xantusia and Lepidophyma, and that the large-bodied Channel Island endemic X. riversiana is a distinct, early lineage that may form the sister group to the small-bodied congeners of the mainland.
Noonan, B. P., Pramuk, J. B., Bezy, R. L., Sinclair, E. A., de Queiroz, K., & Sites Jr, J. W. (2013). Phylogenetic relationships within the lizard clade Xantusiidae: Molecular Phylogenetics & Evolution 69:109-122.