Molecular approaches to phylogeny of Abronia (Anguidae : Gerrhonotinae), with emphasis on relationships in subgenus Auriculabronia

Phylogenetic relationships of Middle American anguid lizards of the genus A bronia were investigated using sequence data from the mitochondrial 12S rib osomal RNA gene (350 bp), cytochrome b gene (364 bp), and 30 previously des cribed morphological characters. Emphasis was placed on species in the subg enus Auriculabronia. Both genes contain substantial phylogenetic informatio n, with cytochrome b roughly twice as variable as 12S. All analyses (separa te and combined datasets) support monophyly of Auriculabronia and, within t his group, existence of a clade consisting of A. aurita, A. anzuetoi, and A . campbelli. Of three populations of A. aurita examined, one from Jalapa (e astern Guatemala) is divergent from the others for both genes and probably represents an undescribed species. The enigmatic and newly described specie s, A. frosti, is highly divergent from all other species examined and, unli ke all other described Abronia from Guatemala, does not appear to belong to subgenus Auriculabronia. Although divergences within Auriculabronia appear relatively shallow, deeper divergences are apparent for A. frosti and for three species from Mexico (A. mixteca, A. sp. "Guerrero," and A. ornelasi). This is consistent with a temporal sequence of orogenies in the area that successively isolated these lizards in highland habitat islands. Our analys is supports monophyly of Abronia and suggests that the genera Barisia and M esaspis may be sister to one another, with this clade being sister to Abron ia.