tridens, Hemigrammus Eigenmann [C. H.] in Eigenmann & Ogle 1907:15 [Proceedings of the United States National Museum v. 33 (no. 1556); ref. 1266] Arroyo Pypucu, Río Paraguay basin, Paraguay. Holotype: CAS 58609 [ex IU 11262]. Paratypes: CAS 61474 [ex IU 11262a] (1) Arroyo Pypucu (= Arroyo Piry-Pucu). •Valid as Hyphessobrycon tridens (Eigenmann 1907) -- (Zarske & Géry 2002:26 [ref. 26553]). •Valid as Hemigrammus tridens Eigenmann 1907 -- (Britski et al. 1999:40 [ref. 24147], Lima & Oyakawa in Reis et al. 2003:133 [ref. 27061], Bertaco & Carvalho 2005:147 [ref. 28675], Marinho et al. 2008:59 [ref. 29547], Carvalho et al. 2010:253 [ref. 30862], Sarmiento et al. 2014:184 [ref. 35004], Azpelicueta & Koerber 2017:67 [ref. 35220], Koerber et al. 2017:40 [ref. 35267], Koerber et al. 2017:4 [ref. 35632], DoNascimiento et al. 2017:[8] [ref. 35679], Koerber et al. 2019:5 [ref. 36736], Albornoz-Garzón et al. 2019:938 [ref. 36872], Mirande & Koerber 2020:2 [ref. 37594], Careaga et al. 2020:75 [ref. 37774]). Current status: Valid as Hemigrammus tridens Eigenmann 1907. Characidae: Stethaprioninae. Distribution: South America: Paraguay-Paraná River basins (Brazil, Paraguay, Argentina and Bolivia). Habitat: freshwater.