Exostoma kottelati, a new species of catfish (Teleostei: Sisoridae) from Arunachal Pradesh, India.

Exostoma kottelati, new species, is described from the Ranga River, Brahmaputra basin, in Arunachal Pradesh state, northeastern India. It differs from congeners in the Brahmaputra River basin in having a longer adipose-fin base (33.4-36.0 % SL vs. 23.4-32.9), a greater (except E. mangdechhuensis) pre-pelvic length (45.6-47.3 % SL vs. 39.3-44.6) and a greater pre-anal length (73.9-76.5 % SL vs. 62.2-70.1). It further differs from all known congeners by the following unique combination characters: the adipose fin is distinctly separated from the dorsal procurrent caudal-fin rays, pre-dorsal length 38.9-41.7% SL, adipose-fin base length 33.4-36 % SL, caudal peduncle length 18.7-21.1 % SL, caudal peduncle depth 8.8-9.5 % SL, and body depth at anus 12.5-13.5 % SL. This is the fifth species of Exostoma known from the Brahmaputra River basin.