Phylogeny and Biogeography of the Rana Pipiens Complex: A Biochemical Evaluation

Abstract

The phylogeny of the Rana pipiens complex as supported by cladistic analysis of the enzymatic products of 50 gene loci is presented. Two broadly sympatric groups within the complex are identified and named the Alpha and Beta divisions. Within both of these divisions, a dichotomy exists between North American and Middle American species. The two groups in the Alpha division are recognized as the R. montezumae species group and the R. areolata species group; the two in the Beta division are referred to the R. pipiens species group and the R. berlandieri species group. Most of the species within a species group are distributed parapatrically; some hybridization may take place within narrow zones of sympatry. Limited hybridization also occurs in the two narrow zones of sympatry that exist between members of different species groups in the same division. However, although sympatry between Alpha division species and Beta division species is extensive, interdivisional hybridization is relatively rare.