Eight new freshwater mussels (Unionidae) from tropical Asia.

Freshwater mussels are sensitive to habitat and water quality, revealing the fastest rates of human-mediated global extinction among aquatic animals. These animals are especially diverse in tropical Asia, the faunas of which are characterized by high levels of endemism. Here we describe four new species and four new subspecies of freshwater mussels from Myanmar. Leoparreysia whitteni sp. nov., the smallest representative of this genus, was discovered from the Ayeyarwady and Chindwin rivers. Radiatula myitthanensis sp. nov. and R. chindwinensis sp. nov. were recorded from the Chindwin Basin, and R. mouhoti haungthayawensis ssp. nov. has been discovered from the Haungthayaw River. Indochinella pugio has been revised with a description of three subspecies: I. pugio viridissima ssp. nov. from the Sittaung, Bilin and Bago rivers, I. pugio daweiensis ssp. nov. from the Dawei River, and I. pugio paradoxa ssp. nov. from the Haungthayaw River. Yaukthwa elongatula sp. nov., a peculiar species, conchologically resembling representatives of the genus Solenaia (Gonideinae) with ultra-elongated shell was found in the Chindwin Basin. Our records highlight that tropical Asia harbors numerous, but still overlooked local endemic lineages of freshwater bivalves, which may be on the brink of extinction due to the high anthropogenic and climate change impacts.