A unified phylogeny of the species Sceloporus undulatus is not universally accepted. Morphological, mtDNA and multiple nuclear loci phylogenies have been made but they do not all agree on the relationships of this clade. By and large, it has been accepted that there are four main subspecies--S. u. cowlesi, S. u. tristichus, S. u. consobrinus and S. u. undulatus--but their relationships to one another are still unclear because of conflicting specimens collected chiefly in hybrid zones. Geographic range seems to be a defining factor of the subspecies, but several of them occur in sympatry. Mitochondrial DNA sequence data from collected specimens has provided evidence of successful interbreeding among different geographic subspecies. Current studies may help resolve the species' taxonomy and phylogenetic relationships (Leache 2009).
Leaché, A. D. 2009. Species tree discordance traces to phylogeographic clade boundaries in North American fence lizards (Sceloporus). Systematic Biology 58: 547-559.
No one has provided updates yet.