Abstract
Tachysurus wuyueensis, new species, is described from the Qiantang-Jiang Basin, situated in Suichang County, Zhejiang Province and Xiuning County, Anhui Province, southeast China. The coastal basin drains into the East China Sea. The new species belongs to the T. pratti-T. truncatus group within the genus Tachysurus defined by having a smooth anterior margin of the pectoral-fin spine, short maxillary barbels not extending beyond the base of the pectoral-fin spine, short dorsal spine not exceeding two thirds of head length and an emarginated caudal fin. This new species is distinct from all other species of this group, Tachysurus pratti (Gunther, 1892), T. truncatus (Regan 1913), T. gracilis (Li, Chen & Chan, 2005) and T. brachyrhabdion (Cheng, Ishihara & Zhang, 2008), in having a shorter prepelvic body (length 40.0–46.4% of SL vs. 45.8–54.8%). It further differs from T. pratti, T. truncatus and T. gracilis in having more vertebrae (45–47 vs. 37–44) and more anal fin rays (21–25 vs. 14–20), from T. brachyrhabdion in having a more slender body (depth 10.1–13.5% of HL vs. 13.1–17.6%). Molecular phylogeny, based on the mitochondrial cytochrome b (cyt. b) gene confirms the validity of T. wuyueensis and the T. pratti-T. truncatus group. Furthermore, this study addresses the diagnostic traits distinguishing the T. pratti-T. truncatus group from the T. tenuis-T. crassilabris group which have historically been treated as a single species group due to morphological similarities.