Low genetic divergence but many names in the endemic Patagonian frogs of the genus Atelognathus (Anura, Batrachylidae): A molecular genetic and morphological perspective

Abstract

The seven species of southern South American frogs belonging to the genus Atelognathus occur in a variety of environments, such as the extra-Andean Patagonian steppe, temperate Nothofagus forests, and ecotonal zones between them in Argentina and Chile. Most species are known only from their type localities and sometimes also nearby surrounding areas. The temperate forests and the ecotones are inhabited by A. nitoi, A. ceii, and A. salai. The taxonomic status of these species is evaluated herein using morphological characters and DNA sequences of cytochrome b, control region, and recombination-activating protein 1 gene. In addition, we reevaluate the diagnostic characters proposed in the original description of each species. Contrary to what expected, we found very low genetic divergence among taxa. Both DNA sequence data and morphological characters did not support the current taxonomy arrangement within Atelognathus. We suggest the recognition of only A. nitoi inhabiting the temperate forests, with A. ceii and A. salai being junior synonyms. This species putatively expanded in a northwards direction across Patagonia, undergoing a recent demographic expansion from southern populations.