Gibbosula sinensis, a new species on the verge of extinction of the world’s most threatened freshwater mussel family Margaritiferidae Henderson, 1929 from China (Bivalvia, Palaeoheterodonta, Unionida)

A new species of freshwater mussel, Gibbosula sinensis Z.-G. Chen, Y.-T. Dai, H. Chen & X.-P. Wu, sp. nov. , is described from the lower Lancangjiang River Basin in Yunnan, China based on comparative morphology and molecular phylogeny. The new species can be distinguished from congeners by the oblong, slender, very curved, relatively thin, fragile, and rather smooth shell, the front end of the shell higher than the posterior end, and the special habitat selection. The new species is on the verge of extinction and urgently requires attention and protection.