How little is known about “the little brown frogs”: description of three new species of the genus Leptobrachella (Anura: Megophryidae) from Yunnan Province, China

Asian leaf-litter toads of the genus Leptobrachella represent a great anuran diversification in Asia. Previous studies have suggested that the diversity of this genus is still underestimated. During herpetological surveys from 2013 to 2018, a series of Leptobrachella specimens were collected from the international border areas in the southern and western parts of Yunnan Province, China. Subsequent analyses based on morphological and molecular data revealed three distinct and previously unknown lineages, which we formally describe as three new species herein. Among them, we describe a new species that occurs at the highest known elevation for Leptobrachella in China. Four species of Leptobrachella, including two new species, are found in the same reserve. Furthermore, our results suggest that the population from Longchuan County, Yunnan, may represent an additional new species of Leptobrachella, although we tentatively assigned it to Leptobrachella cf. yingjiangensis due to the small sample size examined. Lastly, we provide the first description of females of L. yingjiangensis. Our results further highlight that both micro-endemism and sympatric distributions of species are common patterns in Leptobrachella, that contribute to taxonomic and conservation challenges in these frogs. We provide an identification key for Leptobrachella known to occur in Yunnan. Given the lack of knowledge on species diversity of Leptobrachella along international border areas, we recommend that future studies include trans-boundary collaborative surveys.