An extinct species of Tchangmargarya (Gastropoda: Viviparidae) from quaternary lacustrine deposits of a group of vanished lakes in Yunnan, China

ABSTRACT An extinct freshwater molluscan fauna has been discovered from Quaternary lacustrine deposits of a recently vanished group of lakes and surrounding lacustrine deposits in the Luliang Basin, Yunnan Province, China. Three species of Tchangmargarya He, 2013 are dominant and distributed sympatrically here. One of them is new to science. Here we describe the three Tchangmargarya species from the Luliang Basin, including the new species, Tchangmargarya cuan n. sp., and compare the species composition of this fauna with the other extant lacustrine mollusc fauna of Yunnan. The vanished lakes group in Luliang is the first case of sympatric distribution within Tchangmargarya. It is considered to have once been a diversity hotspot of Tchangmargarya and represents a vanished Quaternary lacustrine habitat in Yunnan.