gracilior, Pygidium Eigenmann [C. H.] 1912:213 [Memoirs of the Carnegie Museum v. 5 (no. 1); ref. 1227] Erukin, Potaro River system, Guyana. Holotype (unique): FMNH 53264 [ex CM 1730]. Type catalog: Henn 1928:80 [ref. 12305], Ibarra & Stewart 1987:72 [ref. 12367], Ferraris 2007:407 [ref. 29155]. •Valid as Trichomycterus gracilior (Eigenmann 1912) -- (Burgess 1989:322 [ref. 12860], Lasso & Provenzano 2003:1146 [ref. 26951]). •Valid as Ituglanis gracilior (Eigenmann 1912) -- (Costa & Bockmann 1993:43 [ref. 21010], Burgess & Finley 1996:168 [ref. 22901], Fernández & Bichuette 2002:277 [ref. 26539], de Pinna & Wosiacki in Reis et al. 2003:274 [ref. 27061], de Pinna & Keith 2003:873 [ref. 27831], Datovo & Landim 2005:462 [ref. 28558], Sarmento-Soares et al. 2006:310 [ref. 28814], Ferraris 2007:407 [ref. 29155], Wosiacki et al. 2012:551 [ref. 32291], Lima et al. 2013:522 [ref. 32912], Ferrer et al. 2015:386 [ref. 33964], Datovo et al. 2016:440 [ref. 34783], Castro & Wosiacki 2017:216 [ref. 35201], Ferrer & Donin 2017:8 [ref. 35614], Taphorn et al. 2022:56 [ref. 41297]). Current status: Valid as Ituglanis gracilior (Eigenmann 1912). Trichomycteridae: Trichomycterinae. Distribution: South America: Guyana and Venezuela. Habitat: freshwater.