aculeatus, Chaetostomus Perugia [A.] 1891:637 [37] [Annali del Museo Civico di Storia Naturale di Genova (Serie 2) v. 10; ref. 3431] Río Paraguay, Asuncion, Paraguay. Holotype (unique): MSNG 8937. Type catalog: Tortonese 1963:311 [ref. 10351], Ferraris 2007:272 [ref. 29155]. On p. 37 of separate. Original genus is correctly Chaetostoma. •Valid as Megalancistrus aculeatus (Perugia 1891) -- (Isbrücker 1980:52 [ref. 2303], Burgess 1989:434 [ref. 12860], Gómez & Chebez 1996:65 [ref. 23791], Sverlij et al. 1998:71 [ref. 27632] as Perugia 1891, Britski et al. 1999:134 [ref. 24147], Isbrücker 2002:23 [ref. 27178]). •Synonym of Megalancistrus parananus (Peters 1881) -- (Isbrücker 2001:26 [ref. 25653], Isbrücker 2002:13 [ref. 27178], Fisch-Muller in Reis et al. 2003:390 [ref. 27061], Ferraris 2007:272 [ref. 29155], Litz & Koerber 2014:25 [ref. 33622], Mirande & Koerber 2015:42 [ref. 35117], Koerber et al. 2017:64 [ref. 35267]). Current status: Synonym of Megalancistrus parananus (Peters 1881). Loricariidae: Hypostominae. Habitat: freshwater.