opisthodon, Grammonus Smith [J. L. B.] 1934:92, Pl. 6 (fig. B) [Transactions of the Royal Society of South Africa v. 22 (pt 1); ref. 4064] Port Alfred, South Africa, southwestern Indian Ocean. Holotype (unique): SAIAB [formerly RUSI] 297. •Valid as Grammonoides opisthodon (Smith 1934) -- (Cohen & Nielsen 1978:48 [ref. 881], Cohen 1986:356 [ref. 5646]). •Not treated in Grammonus -- (Nielsen & Prokofiev 2010 [ref. 30790]). •Valid as Grammonus opisthodon Smith 1934 -- (Nielsen & Cohen in Nielsen et al. 1999:104 [ref. 24448], Møller et al. 2016:Appendix A [ref. 34432] in Bythitidae, Anderson & Cohen 2022:264 [ref. 39707]). Current status: Valid as Grammonus opisthodon Smith 1934. Bythitidae. Distribution: Southeastern Atlantic, southwestern Indian Ocean: Camps Bay south to Cape of Good Hope (South Africa), then east to Port Alfred (Eastern Cape, South Africa). Habitat: marine.