gymnogaster, Sicydium Ogilvie-Grant [W. R.] 1884:158, Pl. 11 (fig. 2), Pl. 12 (fig. 6) [Proceedings of the Zoological Society of London 1884 (pt 2) (art. 1) (for 4 Mar. 1884); ref. 18151] Misantla, Veracruz, Mexico. Syntypes: BMNH 1873.6.5.2-4 (3) Vera Cruz, BMNH 1880.4.7.18-20 (3) s. Mexico. •Valid as Sicydium gymnogaster Ogilvie-Grant 1884 -- (Espinosa Pérez et al. 1993:75 [ref. 22290], Hoese in Fischer et al. 1995:1135 [ref. 22829], Bussing 1996:823 [ref. 22890], Castro-Aguirre et al. 1999:426 [ref. 24550], Murdy & Hoese 2003:1795 [ref. 27111], Kullander in Reis et al. 2003:662 [ref. 27061], Nelson et al. 2004:173 [ref. 27807], McEachran & Fechhelm 2005:728 [ref. 28815], Miller 2006:400 [ref. 28615], Scharpf 2009:14 [ref. 30400], Matamoros et al. 2009:25 [ref. 31241], Van Tassell 2011:145 [ref. 31732], de Lucena et al.2013:142 [ref. 32517], Page et al. 2013:179 [ref. 32708], Parenti 2021:415 [ref. 38603], Page et al. 2023:124 [ref. 40505]). Current status: Valid as Sicydium gymnogaster Ogilvie-Grant 1884. Oxudercidae: Sicydiinae. Distribution: Western Atlantic: Atlantic slope rivers of Mexico and Honduras [amphidromous]. Habitat: freshwater, brackish, marine.