Ribosomal DNA and the Phylogeny of Frogs

Phylogenetic analysis of 1656 aligned sites in the 28S ribosomal RNA gene of frogs supports some of the recently recognized higher groups of anurans but provides counter-support for others. The 28S rDNA data support the monophyly of the recently recognized Pipanura (mesobatrachians plus neobatrachians), which in turn indicates paraphyly of archaeobatrachians. Mesobatrachians (pelobatoids plus pipoids), which are either considered paraphyletic or weakly supported as monophyletic in morphological analyses, also receive support as a monophyletic group from the 28S rDNA data. Hyloidea (= Bufonoidea), which is widely recognized but lacks morphological support, receives some molecular support as being monophyletic. However, Ranoidea, which is supported by morphology, is counter-supported by ribosomal DNA. In particular, dendrobatids do not group with ranids (but sometimes group with hyloids). A combined analysis of the molecular data with the morphological data of Duellman and Trueb (1986:Biology of Amphibians) supports Pipanura, Mesobatrachia, Neobatrachia, and Hyloidea, but shows the ranoids as paraphyletic (with Dendrobatidae related to Hyloidea). The agreement between molecular and morphological data in several regions of the anuran tree indicates an approaching stabilization of traditionally labile higher frog classification.