Phylogenetic Relationships of Extant Pelobatoid Frogs (Anura: Pelobatoidea): Evidence from Adult Morphology

Abstract

The phylogenetic relationships of the Pelobatoidea, the most specious clade of basal anurans, are poorly understood. 1 conducted a phylogenetic analysis of 14 extant pelobatoid taxa (representing all recognized extant species of the family Pelobatidae and representative taxa of Megophryidae and Pelodytidae) and six outgroup taxa by examining alcohol-preserved specimens, dried skeletons, and cleared and double-stained skeletal preparations. Analysis of 73 characters from primarily adult morphology resulted in the discovery of six most parsimonious trees, each with 251 steps. The analysis supports Pelobatoidea and Pipoidea as sister taxa. Within the Pelobatoidea, Pelodytidae is the sister group to Pelobatidae, and Megophryidae is the sister taxon to [Pelobatidae + Pelodytidae]. Within the Pelobatidae, the monophyly of Pelobates, Scaphiopus, and Spea is supported. This paper summarizes and redefines morphological characters that historically have been used in the study of extant pelobatoid systematics and adds new, informative morphological characters. This should create a framework upon which further phylogenetic analyses of this group can be conducted.