Abstract:The China-Vietnam border region is a well-known biodiversity hotspot, harboring a striking diversity of species and endemism. New species and new records have been reported on both sides of the border in recent years. Although Paramesotriton deloustali was first recorded in China in 2017, only the complete mitochondrial sequence was provided, and no other information was available, including its detailed distribution in China and morphological characteristics. Here we describe P. deloustali from China based on six newly collected specimens (four males and two females) from Dawishan Reserve (22°37′ N, 103°52′ E, altitude 350 m) in Hekou County, Honghe Hani and Yi Autonomous Prefecture, Yunnan Province (Table 1). The morphological characters of the Chinese specimens align closely with the type series from Vietnam (Fig. 1, 2), and the phylogenetic analyses based on the cytochrome coxidase subunit I (COI) gene revealed a low genetic differentiation (p-distance is 0.6%) between Chinese population and those from its type locality at Tam Dao, Vinh Phuc Province, northern Vietnam. Additionally, our newly collected specimens have low genetic divergence (p-distance is 0.5%) from the sequences of the former record in Yunnan (Fig. 3). P. deloustali is currently recorded in the China-Vietnam border area only, and it is found in a narrow area with unknown population size and trends. We recommend further international collaboration between China and Vietnam to understand the distribution and conservation situation of this species better.