Chinese scientitsts have described a new species of balitorid loach from southern China.
The new loach, named Metahomaloptera longicauda, is described in a recent issue of the journal Zootaxa by Jian Yang, Xiaoyong Chen and Junxing Yang.
The new species is only known from the Jinsha Jiang drainage in southern China (the Jinsha Jiang is a southern tributary of the Yangtze River drainage in central China).
Prior to this study, only a single species of Metahomaloptera with two subsepcies were known: M. omeihensis omeihensis and M. omeihensis hangshuiensis. Metahomaloptera longicauda can be distinguished from from M. omeiensis omeiensis in a more anteriorly positioned dorsal fin insertion (anterior to middle of body vs. at middle of body), a longer pectoral fin (reaching beyond dorsal-fin origin vs. not reaching), anal fin not reaching (vs. reaching) caudal-fin base, pelvic fin reaching to or beyond (vs. not reaching) anus (vs. pelvic fin far from anus), narrower head (19.4"22.6% SL vs. 22.7"30.2), shorter preanal length (69.0"74.3% SL vs. 80.7"87.4), longer (17.1"20.7% SL vs. 8.4"11.9) and more slender (caudal-peduncle depth 33.7"43.1% caudal-peduncle length vs. 62.7"87.6) caudal peduncle, smaller eye (diameter 14.6"16.6% HL vs. 16.7"23.9), and wider mouth (width 63.2"75.5% body width at pectoral-fin origin vs. 30.3"42.3).
Metahomaloptera longicauda can be distinguished from M. omeiensis hangshuiensis in having fewer dark blotches along the median dorsal line from occipital region to base of caudal fin (8"9 vs. 10"15), a longer pectoral fin (reaching beyond dorsal-fin origin vs. not reaching), more lateral-line scales (66"78 vs. 59"63), fewer branched pectoral rays (11"15 vs. 16"18), fewer branched pelvic rays (10"12 vs. 13"15), and a longer (17.1"20.7% SL vs. 7.1"10) and more slender (caudal peduncle depth 33.7"43.1% caudal peduncle length vs. 76.9"111.1) caudal peduncle.
For more information, see the paper: Yang, J, X-Y Chen and J-X Yang (2007) A new species of Metahomaloptera (Teleostei: Balitoridae) from China. Zootaxa 1526, 63"68.