pachycephalus, Opsariichthys Günther [A.] 1868:296 [Catalogue of the fishes in the British Museum v. 7; ref. 1990] Taiwan. Syntypes: (at least 6) BMNH 1865.5.2.31-34 (4), 1865.5.2.60 (1). Type catalog: Ho & Shao 2011:29 [ref. 31432]. •Synonym of Zacco temmincki (Temminck & Schlegel 1846). •Valid as Zacco pachycephalus (Günther 1868) -- (Bănărescu 1968:306 [ref. 20605], Zhu 1995:26 [ref. 25213], Wang et al. 1997:170 [ref. 25517], Chen & Chu in Chen et al. 1998:45 [ref. 23878], Sado & Kimura 2002:353 [ref. 26498], Ma et al. 2006:343 [ref. 28735], Chen et al. 2009 [ref. 30298]). •Valid as Opsariichthys pachycephalus Günther 1868 -- (Chen et al. 2009:170 [ref. 30298], Ho & Shao 2011:29 [ref. 31432], Huynh & Chen 2014:143 [ref. 33158], Zhang et al. 2016:50 [ref. 34477] [not China], Wang et al. 2019:[6] [ref. 36521], Peng et al. 2024:28 [ref. 41610]). Current status: Valid as Opsariichthys pachycephalus Günther 1868. Xenocyprididae. Distribution: East Asia: Taiwan. Habitat: freshwater.