Taxonomic reassessment of Hebius atemporalis (Bourret, 1934) (Squamata, Natricidae), with the description of a new species from China

Hebius atemporalis (Bourret, 1934) has been reported from both northern Vietnam and southern China. Previous studies revealed deep genetic divergence between the Chinese and Vietnamese populations; however, no comprehensive taxonomic revision has examined the phylogenetic relationships and taxonomic status of these divergent lineages. Here, we present an integrative taxonomic reassessment of the H. atemporalis complex, combining detailed morphological comparisons and molecular data. As a result, we identify and describe a distinct new species, Hebius malnatei sp. nov ., endemic to the Yunnan-Guizhou Plateau, China. The new species can be distinguished from H. atemporalis sensu stricto by its larger adult body size, shorter relative tail length, higher numbers of ventrals and subcaudals, and distinctive coloration characterized by the absence of a nuchal collar. Phylogenetic analyses based on cytochrome b sequences consistently recover Hebius malnatei sp. nov . as the sister taxon of H. atemporalis s. str., with uncorrected p -distances of 8.0–9.8%. According to the IUCN Red List criteria, we recommend assigning Hebius malnatei sp. nov . to the category Least Concern (LC). This study highlights the need for taxonomic revision of widely distributed Hebius species and underscores the role of the Yunnan-Guizhou Plateau uplift in promoting species diversification.