A New Species of the Gudgeon Genus Huigobio Fang, 1938 (cypriniformes: Cyprinidae) from the Yangtze River Basin, Southern China.

During revision of the genus Microphysogobio Mori, 1934, we discovered a new species of Huigobio from the Yangtze River Basin in China. The new species, named Huigobio heterocheilus sp. nov., can be distinguished from its congeners by a combination of the following characters: medial pad on lower lip not visible; ventral region scaleless before pelvic-fin insertion; lateral-line scales 39–40; caudal peduncle depth 49.2%–59.1% of length; barbel length 6.6%–10.7% of head length; black blotch between anterior margin of eye and upper lip. Using the K2P model and cytochrome b (cyt b) sequences, interspecific genetic distances between the new species and Huigobio exilicauda Jiang & Zhang, 2013 and Huigobio chenhsienensis Fang, 1938 were 13.2% and 15.1%, respectively. The new species is known from the upper reaches of the Xiangjiang River in the middle Yangtze River Basin. A diagnostic key for species of Huigobio Fang, 1938 is provided.