Redescription and range extension of Pareas dulongjiangensis Liu, Yang, Rao, Guo & Rao, 2023 (Squamata: Pareidae)

The Dulongjiang slug-eating snake Pareas dulongjiangensis was described based on a single preserved female specimen collected in Gongshan County, Nujiang Prefecture, Yunnan Province, China. Consequently, important aspects of its morphology, live coloration, sexual dimorphism, and geographic distribution have remained poorly understood. In this study, we report four additional specimens collected from Dulongjiang Township, Yunnan Province, China.

Molecular phylogenetic analyses based on mitochondrial DNA confirm that these specimens cluster with P. dulongjiangensis, showing minimal genetic divergence from the type specimen (uncorrected p -distance of 0.0–0.9% in the Cyt b gene). The newly available material allow us to refine the diagnosis of the species, provide a broader redescription, and document intraspecific variation, including previously unknown male specimens and hemipenial morphology.

We also present the first photographs of the species in life. Re-examination of a specimen from Hkakabo Razi National Park, Kachin State, northern Myanmar, previously referred to as Pareas sp. by Vogel et al. (2021), indicates that it represents P. dulongjiangensis, thereby extending the known distribution of the species to Myanmar. In addition, we clarify an important diagnostic character by demonstrating that the species possesses a single prefrontal scale, correcting earlier reports of paired prefrontals.

Our results highlight the importance of adequate sampling in taxonomic studies, as reliance on a single specimen may lead to misinterpretation of intraspecific variation. Further integrative studies with broader sampling are required to better resolve morphological variation and species boundaries within the Pareas hamptoni species group.