angustifrons, Tetragonopterus Regan [C. T.] 1908:172, Pl. 26 (fig. 5) [Biologia Centrali-Americana; ref. 18482] Mexico [probably southern Gulf of Mexico versant]. Lectotype: BMNH 1857.7.31.9. Paralectotypes: BMNH 2016.9.13.1-2 (2). Lectotype selected by Schmitter-Soto 2017:1360 [ref. 35414]? •Valid as Astyanax angustifrons (Regan 1908) -- (Buckup in Reis et al. 2003:107 [ref. 27061], Marinho & Birindelli 2013:46 [ref. 32569], Marinho & Ohara 2013:476 [ref. 32713], Schmitter-Soto 2017:1358 [ref. 35414], Page et al. 2023:76 [ref. 40505]). Current status: Valid as Astyanax angustifrons (Regan 1908). Characidae: Stethaprioninae. Distribution: Southern North America, Middle America: Campeche and Tabasco (Mexico) south to northern Petén (Guatemala). Habitat: freshwater.