系统进化与生物地理学（杨君兴）知识库

A new species of Metahomaloptera, M. longicauda, is described from the lower Jinsha River, China. The new species is distinguished from other species of Metahomaloptera by the following combination of characters: pectoral fin with 11 15 branched rays, tip of pectoral fin extending beyond origin of dorsal fin, pelvic fin with 10 - 12 branched rays, pelvic-fin tip reaching or extending beyond anus, dorsal fin inserting before middle of body, tip of dorsal fin far from vertical line of caudal-fin base, head width 19.4 - 22.6% SL, pre-pectoral length 8.4 - 9.9% SL, pre-anal length 69.0 - 74.3% SL, caudal peduncle length 17.1 - 20.7% SL, eye diameter 14.6 - 16.6% HL, caudal peduncle depth 33.7 - 43.1% caudal peduncle length, mouth width 63.2 - 75.5% body width at pectoral-fin origin.