A new species of freshwater snail Tchangmargarya (Gastropoda: Viviparidae) endemic to a vanished small lake in Yunnan, China.

Habitat loss poses a grave threat to endemic species with narrow distributions. Some species become extinct even before scientific identification due to habitat destruction. Here, a probable example is reported based on some recent and subfossil shells from an almost disappeared wetland lake in Yunnan Province, China. A new ornamented freshwater snail species,Tchangmargarya ziyin. sp., is recognised and described based on morphological comparison with the otherTchangmargaryaspecies. The subfossil specimens of the new species show a great similarity toTchangmargrya yangtsunghaiensis(Tchang & Tsi, 1949), indicating their potentially close relationship. The discovery of the new species demonstrates that the plateau lakes of Yunnan, even the small ones, have a high biodiversity and endemism. Furthermore, it enriches the knowledge of the distribution ofTchangmargaryaand provides further evidence that the Liangwang Mountains are a significant biogeographic barrier to three endemic viviparid genera (Margarya,Anularya andTchangmargarya) of Yunnan. Since the only known habitat of this species has been mostly landfilled due to the construction of a golf course and villas, this species possibly has already gone extinct. In order to implement conservation measures more efficiently, more comprehensive surveys should be conducted in all plateau lakes of Yunnan, including those that might seem insignificant. [ABSTRACT FROM PUBLISHER]