alga, Chaetostomus Cope [E. D.] 1872:287, Pl. 15 (fig. 3) [Proceedings of the Academy of Natural Sciences of Philadelphia v. 23; ref. 921] Río Ambyiacu, Peru. Syntypes: ANSP 16461-62 (2). Type catalog: Böhlke 1984:121 [ref. 13621], Ferraris 2007:221 [ref. 29155]. Original genus is correctly Chaetostoma. •Synonym of Ancistrus hoplogenys (Günther 1864) -- (Fisch-Muller in Reis et al. 2003:376 [ref. 27061], Ferraris 2007:221 [ref. 29155], Koerber et al. 2017:60 [ref. 35267]). •Valid as Ancistrus alga (Cope 1872) -- (Isbrücker 1980:66 [ref. 2303], Ortega & Vari 1986:16 [ref. 9708], Burgess 1989:436 [ref. 12860], Isbrücker 2001:25, 26 [ref. 25653], Isbrücker 2002:11 [ref. 27178], Provenzano & Barriga-Salazar 2018:217 [ref. 36344], Meza-Vargas et al. 2021:25 [ref. 39298]). Current status: Valid as Ancistrus alga (Cope 1872). Loricariidae: Hypostominae. Distribution: South America: lower Napo River basin, upper Amazon basin (Ecuador and Peru). Habitat: freshwater.