retrospina, Brachychalcinus Boulenger [G. A.] 1892:12, Pl. 2 (fig. 2) [Annals and Magazine of Natural History (Series 6) v. 10 (no. 55) (art. 2); ref. 533] Santa Cruz, Mato Grosso, Brazil. Lectotype: BMNH 1892.4.20.36. Paralectotypes: BMNH 1892.4.20.37-38 (2) [according to Reis 1989 these belong to Poptella paraguayensis]. Lectotype selected by Eigenmann & Myers 1929:508 [ref. 1263]. •Valid as Brachychalcinus retrospina Boulenger 1892 -- (Reis 1989:70 [ref. 14219], Britski et al. 1999:56 [ref. 24147], Reis in Reis et al. 2003:209 [ref. 27061], Koerber et al. 2017:32 [ref. 35267], Garcia-Ayala et al. 2017:571 [ref. 35695], Garcia-Ayala et al. 2024:9 [ref. 40855]). Current status: Valid as Brachychalcinus retrospina Boulenger 1892. Acestrorhamphidae: Stethaprioninae. Distribution: South America: Paraguay River basin, Brazil and Paraguay. Habitat: freshwater.