megacephalus, Chaetostomus Günther [A.] 1868:476 [Annals and Magazine of Natural History (Series 4) v. 1 (no. 6) (art. 56); ref. 1992] Probably Suriname. Holotype (unique): BMNH 1978.9.12.3. Type catalog: Ferraris 2007:244 [ref. 29155]. Original genus is correctly Chaetostoma. Also published in Günther (Sept.) 1868:232 [ref. 5756]. •Valid as Hemiancistrus megacephalus (Günther 1868) -- (Isbrücker 1980:51 [ref. 2303], Burgess 1989:434 [ref. 12860], Isbrücker 2001:26, 27 [ref. 25653], Isbrücker 2002:17 [ref. 27178], Cardoso & Lucinda 2003:74 [ref. 26858], Fisch-Muller in Reis et al. 2003:386 [ref. 27061], Ferraris 2007:244 [ref. 29155], DoNascimiento 2016:532 [ref. 34727]). •Valid as "Pseudancistrus" megacephalus (Günther 1868) -- (Armbruster et al. 2015:99 [ref. 33670]). Current status: Valid as Pseudancistrus megacephalus (Günther 1868). Loricariidae: Hypostominae. Distribution: Essequibo basin, Guyana and coastal drainages of Suriname: Guyana and Suriname. Habitat: freshwater.