摘要Despite continuous progress made on the taxonomy of the genus Tropidophorus,the Lao Water Skink,T.laotus,is only known from brief descriptions of its syntypes in historical literature.Here we designate a lectotype and paralectotype of the species,redescribe the species based on the type series and newly collected topotypes,provide the first colored photographs of taxonomically-verified individuals,and estimate its phylogenetic position using mitochondrial DNA data for the first time.Using these comparable data,we confirm that the previously identified"T.berdmorei"population from southern Yunnan Province,China,represents a distinct new species that is closely related and morphologically similar to T.laotus,but differs from true T.laotus by having considerable genetic divergence(4.7%-4.8%for 12S,3.2%-4.2%for 16S)and distinct morphological characters(e.g.,undivided frontonasal scales and a distinct color pattern of the throat).The southern Yunnan population is therefore described as a new species.With the above newly acquired data,we update the checklist and the provincial-level distribution of the genus Tropidophorus in China and compile an updated key to all recognized species of the genus from China and Indochina.