robustulus, Hemigrammus Cope [E. D.] 1870:561 [Proceedings of the American Philosophical Society v. 11; ref. 914] Pebas, Peru. Lectotype: ANSP 8037. Paralectotypes: ANSP 8038-52 (15). Type catalog: Böhlke 1984:53 [ref. 13621] as holotype (8037) and paratypes. Lectotype selected by Fowler 1906:335 [ref. 1373]. •Valid as Hyphessobrycon robustulus (Cope 1870) -- (Ortega & Vari 1986:8 [ref. 9708], Zarske & Géry 1997:310 [ref. 23715], Lima & Malabarba in Reis et al. 2003:139 [ref. 27061], Barriga Salazar 2014:107 [ref. 35745], Meza-Vargas et al. 2021:18 [ref. 39298]). •Species inquirenda -- (Lima et al. 2024:205 [ref. 40817]). Nomen Dubium. Current status: Uncertain as Hyphessobrycon robustulus (Cope 1870). Acestrorhamphidae: Hyphessobryconinae. Distribution: South America: only known from the type series. Habitat: freshwater.