What is "exostoma"

Exostoma is a genus of sisorid catfishes native to Asia. These species are distributed in the Brahmaputra drainage of northeast India, and east and south to the Salween drainages in Burma. E. berdmorei is found in the Sittang and Salween drainages in Burma. E. labiatum is known from the Brahmaputra drainage in northeast India, but has also been recorded in the Salween drainage in Burma, the Ayeyarwady drainage in China, and the Brahmaputra drainage in Tibet and Burma. E. stuarti is from the Ayeyarwady River of Burma and India; however, it has not been collected since its original discovery. E. labiatum is found in mountain rapids.

In a 2007 checklist of sisorid and erethistid catfishes, Thomson lists E. stuarti and E. vinciguerrae as valid species. In a 2007 checklist of catfishes, Ferraris lists these two species as species inquerendae, noting that these species are either treated as valid or as synonyms of E. labiatum.