gracilis, Cottus Heckel [J. J.] 1837:148 [Annalen des Wiener Museums der Naturgeschichte v. 2 (no. 1) (for 1840); ref. 2079] New York, U.S.A. Holotype (unique): NMW 6422. •Synonym of Cottus cognatus Richardson 1836 -- (Smith 1986:358 [ref. 22186], Scott & Crossman 1998:835 [ref. 24570], Scharpf 2008:9 [ref. 30399]). •Synonym of Cottus cognatus Richardson 1837, but a valid subspecies -- (Chereshnev 1996:606 [ref. 24659], Reshetnikov et al. 1997:758 [ref. 24702], Sideleva 1998:151 [ref. 23595]). Current status: Synonym of Cottus cognatus Richardson 1836. Cottidae. Habitat: freshwater, brackish.