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

Abstract

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.

Genetic and morphometric analyses of historical type specimens clarify the taxonomy of the Ethiopian Leptopelis gramineus species complex (Anura, Arthroleptidae)

“…In this species complex, including historical type specimens was necessary to assign the correct names to newly-discovered and previously-synonymised taxa. The present case is reminiscent of the situation reported in Ethiopian Ptychadena, where the analysis of type specimens allowed us to clarify the convoluted taxonomy of the group (Goutte et al 2021;Reyes-Velasco et al 2021).…”

“…The L. gramineus species complex thus adds to a growing list of groups that have diversified in the Ethiopian Highlands (e.g. Goutte et al 2019Goutte et al , 2021Koppetsch 2020;Kostin et al 2020;Soultan et al 2020) and highlights the ecological importance of this unique region.…”

Coloring inside the lines: genomic architecture and evolution of a widespread color pattern in frogs

“…For P. robeensis, leaves are color-coded by haplotypes (green for thin and red for wide). Within P. robeensis, haplotypes are grouped by color pattern, while across the Ptychadena neumanni complex, they are grouped according to species relatedness and form the three clades previously described 24 (Fig. 2a).…”

“…To investigate the molecular and cellular mechanisms underlying the vertebral stripe in anurans, we focused on a radiation of terrestrial frogs, the Ptychadena neumanni species complex. This monophyletic group encompasses 12 species 24 , which all present vertebral stripe polymorphism (the stripe could be thin, wide, or absent), except for two species: P. harenna, in which the vertebral stripe morph is always absent and P. cooperi, for which all individuals present a thin vertebral stripe (Fig. 2a and 2b).…”

“…After examination of the low-coverage genomic dataset (n=61 individuals; SNPs PCA and visual examination in IGV), we realized that five individuals were hybrids , likely resulting from the crossing of P. robeensis and P. levenorum, a closely related species with a partially overlapping distribution range 24 . After removing the hybrids, the dataset comprised 17,797,568 SNPs.…”