microstomus, Hemigrammus Durbin [M. L.] in Eigenmann 1918:165 [Memoirs of the Museum of Comparative Zoology v. 43 (pt 2); ref. 1240] Santarém, Pará, Brazil. Holotype: MCZ 20782 (1 of 9). Paratypes: CAS 42680 [ex IU 12650 & MCZ 20782-3] (2); MCZ 20782 (8 mixed with holotype), 20783 (orig. 10), 20840 (5); USNM 120267 [ex MCZ 20782] (3). Additional original material: CAS 42681 [ex IU 13274 & CM 2944] (2). Type catalog: Vari & Howe 1991:25 [ref. 19022]. Author is M. L. Durbin. First mentioned in Eigenmann 1910:436 [ref. 1224] without description. •Valid as Hemigrammus microstomus Durbin 1918 -- (Taphorn 1992:215 [ref. 23654], Lima & Oyakawa in Reis et al. 2003:132 [ref. 27061], Carvalho et al. 2010:253 [ref. 30862], DoNascimiento et al. 2017:48 [ref. 35633], Meza-Vargas et al. 2021:18 [ref. 39298], Taphorn et al. 2022:15 [ref. 41297]). Current status: Valid as Hemigrammus microstomus Durbin 1918. Acestrorhamphidae: Pristellinae. Distribution: South America: Amazon and Orinoco river basins (Brazil, Colombia, Guyana, Peru and Venezuela). Habitat: freshwater.