ucayalensis, Ageneiosus Castelnau [F. L.] 1855:49, Pl. 17 (fig. 2) [Animaux nouveaux or rares v. 2; ref. 766] Lake near Río Ucayali, Peru. Holotype (unique): MNHN B-0611 (poor condition). Type catalog: Bertin & Estève 1950:16 [ref. 19575], Ferraris 2007:70 [ref. 29155]. •Valid as Ageneiosus ucayalensis Castelnau 1855 -- (Ortega & Vari 1986:14 [ref. 9708], Burgess 1989:286 [ref. 12860], Burgess & Finley 1996:167 [ref. 22901], Britski et al. 1999:94 [ref. 24147], Camargo & Isaac 2001:145 [ref. 27639], Ferraris in Reis et al. 2003:472 [ref. 27061], López et al. 2003:57 [ref. 27366], Schraml 2005:22 [ref. 28585], Ferraris 2007:70 [ref. 29155], Ribeiro & Rapp Py-Daniel 2010:103 [ref. 30759], Barriga Salazar 2014:115 [ref. 35745], Sarmiento et al. 2014:141, 189 [ref. 35004], Mirande & Koerber 2015:30 [ref. 35117], DoNascimiento et al. 2017:86 [ref. 35633], Ribeiro et al. 2017:5, 69 [ref. 35133], Urbano-Bonilla et al. 2018:81 [ref. 35773], Calegari et al. 2019:[99] [ref. 36961], Hashimoto et al. 2020:[3] 16 [ref. 37940], Reis et al. 2020:464 [ref. 38364], Silvano et al. 2020:208 [ref. 38135], Meza-Vargas et al. 2021:22 [ref. 39298], Koerber et al. 2022:57 [ref. 39235], Taphorn et al. 2022:43 [ref. 41297], Limeira-Filho et al. 2024:7 [ref. 41573]). Current status: Valid as Ageneiosus ucayalensis Castelnau 1855. Auchenipteridae: Auchenipterinae. Distribution: South America: Amazon River basin, and coastal rivers of northeastern Brazil (Brazil, Colombia, Guyana and Peru). Habitat: freshwater.