Limnocythere curvispinosa sp. nov. (Crustacea, Ostracoda) from two ancient lakes in the Xiaojiang Fault zone, Yunnan Province, southwestern China

Ancient lakes often harbor endemic species that are invaluable for studying adaptive radiation and speciation. In Yunnan Province, southwestern China, a number of ancient lakes emerged as a result of Cenozoic tectonic activities. Within these lakes, ostracods constitute a crucial component of the ecosystems, yet they remain poorly studied. Here, we describe Limnocythere curvispinosa sp. nov. (Limnocytheridae Sars, 1925) from Fuxian and Yangzong Lakes in east-central Yunnan. This new species belongs to the L. stationis group based on its posteriorly inclined dorsal valve margin and the reduced seventh limb. It can be distinguished from other species in this group by the three long, curved dorsal spines on the right valve, the small antero-dorsal spine on the left valve, and the unique morphology of the hemipenis. Our data indicate that Limnocythere curvispinosa sp. nov. colonized Yangzong Lake by the Early Holocene at the latest, but it is uncertain if it still occurs there today. Some females and a few males of this species still live in Fuxian Lake. Together, Limnocythere curvispinosa sp. nov. , Limnocythere xinanensis Zhao, 1987, and another undescribed but closely related species represent a small evolutionary lineage within the L. stationis group that has inhabited southwestern China since the Early Pleistocene.