A multilocus phylogeny of the genus Sarcohyla (Anura: Hylidae), and an investigation of species boundaries using statistical species delimitation.

The genus Sarcohyla is composed by 24 species endemic to México. Despite the large number of phylogenetic studies focusing on the family Hylidae, the relationships among the species of Sarcohyla are still poorly known, and the scarce numbers of specimens and tissue samples available for some of the species has hampered an appropriate phylogenetic analysis. We present the most comprehensive molecular phylogenetic study of Sarcohyla to date. We included 17 species of the genus Sarcohyla using data from two mitochondrial (ND1 and 12S) and three nuclear genes (Rag-1, Rhod, and POMc). We performed phylogenetic analyses using Bayesian inference, and the absence of conflicts with strong support between the separate gene trees indicates that incomplete lineage sorting and/or introgressive hybridization are negligible. A coalescent-based species-tree analysis of the four independent loci (three nuclear genes+mtDNA) mostly supports the same species-level relationships as the analysis of the concatenated data. By including new samples from additional species and localities, we find that: (1) the widely distributed species S. bistincta is a complex of at least three species, (2) another undescribed species exists in the group, (3) the species S. ephemera is not valid and it corresponds to a junior synonym of S. calthula. In addition, we conducted marginal likelihood estimation and used Bayes factors to test alternative species delimitation models for S. bistincta, the most widespread nominal species in the group. Our findings support three independent lineages of S. bistincta group, which are paraphyletic with respect to S. pentheter and S. calthula.