frenatus, Rivulus Eigenmann [C. H.] 1912:453, 455 [Memoirs of the Carnegie Museum v. 5 (no. 1); ref. 1227] Essequibo River at Gluck Island, Guyana. Holotype (unique): FMNH 53538 [ex CM 1085]. Type catalog: Henn 1928:86 [ref. 12305], Ibarra & Stewart 1987:76 [ref. 12367]. Available from key on p. 453. Name used previously in Eigenmann 1909:51 [ref. 1222] and Eigenmann 1910 [ref. 1224] with reference to type and locality, but without diagnostic characters and therefore not available from either of those publications (Art. 12.1 of the Code). Combined with a neuter genus, the adjective should be frenatum. •Valid as Rivulus frenatus Eigenmann 1912 -- (Huber 1992:202 [ref. 20639], Lazara 2001:274 [ref. 25711], Costa in Reis et al. 2003:536 [ref. 27061], Suijker & Collier 2006:10 [ref. 28729], Costa 2006:153 [ref. 28875] in subgenus Laimosemion). •Valid as Laimosemion frenatum (Eigenmann 1912) -- (Costa 2011:239 [ref. 31655] as frenatus, Vermeulen et al. 2012:188 [ref. 32253] as frenatus, Taphorn et al. 2022:36 [ref. 41297]). Current status: Valid as Laimosemion frenatum (Eigenmann 1912). Rivulidae: Rivulinae. Distribution: South America: Essequibo River basin (Guyana and Suriname) endemic. Habitat: freshwater.