cylindricus, Hemigrammus Durbin [M. L.] 1909:62 [Annals of the Carnegie Museum v. 6 (no. 1); ref. 1166] Tumatumari, Guyana. Holotype: FMNH 53426 [ex CM 1461]. Paratypes: BMNH 1911.10.31.395 (1); CAS 44412-14 [ex IU 11915-17] (1, 4, 5); FMNH 7349 (1), 53037 (1), 53038-40 (3, 5, 1), 69538 (9); MCZ 29974 (1); CAS-SU 21916 (1); USNM 66191 [ex CM] (1); ZMA 100984 (1). Type catalog: Henn 1928:65 [ref. 12305], Böhlke 1953:24 [ref. 12291], Nijssen et al. 1982:18 [ref. 19236], Ibarra & Stewart 1987:44 [ref. 12367], Vari & Howe 1991:24 [ref. 19022]. •Valid as Hemigrammus cylindricus Durbin 1909 -- (Lima & Oyakawa in Reis et al. 2003:131 [ref. 27061], Barriga Salazar 2014:107 [ref. 35745], DoNascimiento et al. 2017:[7] [ref. 35679], Taphorn et al. 2022:15 [ref. 41297]). Current status: Valid as Hemigrammus cylindricus Durbin 1909. Acestrorhamphidae: Pristellinae. Distribution: South America: Essequibo River (Guyana) and ?Ecuador. Habitat: freshwater.