gracilis, Tetragonopterus Lütken [C. F.] (ex Reinhardt) 1875:133 [7] [Oversigt over det Kongelige Danske Videnskabernes Selskabs Forhandlinger og dets Medlemmers Arbeider (Kjøbenhavn) 1874 (no. 3); ref. 2856] Lagoa Santa, 19°38'S, 43°53'W, Brazil. Syntypes: MNHN 0000-9583 [ex ZMUC] (4); NMW 68066 (5); SMNS 2047 (4); ZMB 9201 (1); ZMUC 522-529 (8), 539 (1), 650 (1), 651 (1), 661 (1), 662 (1). Type catalog: Bertin 1948:23 [ref. 19577], Nielsen 1974:46 [ref. 9588], Fricke 1995:9 [ref. 28100], Fricke 2005:26 [ref. 29864] with author as Reinhardt. On p. 7 of separate. Also described in Lütken 1875:217 (and p. XIV of summary), Pl. 5 (fig. 16) [ref. 19674]. Authorship sometimes seen as Reinhardt in Lütken. •Valid as Hyphessobrycon gracilis (Lütken 1875) -- (Fernández & Butí 1996:252 [ref. 22775], Lima & Gerhard 2001:110 [ref. 25355], Britski 2001:21 [ref. 26046]). •Valid as Hemigrammus gracilis (Lütken 1875) -- (Lima & Oyakawa in Reis et al. 2003:131 [ref. 27061], Mendonça & Wosiacki 2011:214 [ref. 31415], DoNascimiento et al. 2017:48 [ref. 35633] [correct?], Silva et al. 2020:6 [ref. 37809], Taphorn et al. 2022:15 [ref. 41297] as cf. gracilis, Lima & Marinho 2024:175 [ref. 40817]). Current status: Valid as Hemigrammus gracilis (Lütken 1875). Acestrorhamphidae: Pristellinae. Distribution: South America: São Francisco River basin (Brazil). Habitat: freshwater.