Balantiocheilos ambusticauda, a new and possibly extinct species of cyprinid fish from Indochina (Cypriniformes: Cyprinidae)

Abstract

Balantiocheilos ambusticauda sp. nov. is described from the Mekong and Chao Phraya river drainages in Indochina (mainland Southeast Asia). It can be distinguished from its only congener, B. melanopterus, in having a shorter snout (27.5–33.9% HL vs. 33.2–39.1), posteriorly directed grooves at rictus curved (vs. straight), and narrower black margins on the pelvic and anal fins (on distal third or less vs. on distal half or more). The possibility that B. ambusticauda is extinct is also discussed.