Taxonomic revision of grass frogs (Ptychadenidae, Ptychadena) endemic to the Ethiopian highlands

Frogs of the genus Ptychadena that inhabit the Ethiopian highlands serve as a model system to understand biogeography, diversification, and adaptations to high elevations. Despite recent studies focusing on the systematics of this group, the taxonomy of the Ptychadena neumanni species complex remains only partially resolved, owing largely to the morphological resemblance of its members. Here, the taxonomy of this historically problematic group of frogs is revised by integrating morphological and molecular analyses on both century-old type specimens and more recently collected material. Based on these multiple lines of evidence, the P. neumanni species complex is shown to be more speciose than previously thought and four new species are described. With the aim of clarifying and stabilizing the taxonomy of the group, six species are also re-described and morphological and acoustic identification keys are provided. This study also establishes species distribution maps and reveals important differences in range size between the members of the P. neumanni complex, calling for adapted conservation measures across the Ethiopian highlands.