alleni, Tetragonopterus Eigenmann [C. H.] & McAtee [W. L.] in Eigenmann, McAtee & Ward 1907:126, Pl. 40 (fig. 2) [Annals of the Carnegie Museum v. 4 (no. 2) (art. 7); ref. 1261] Corumba, río Otuquis, Ascunción, Paraguay. Holotype: CAS 57616 [ex IU 10158]. Paratypes: CAS 57617 [ex IU 10159] (1), 57619 [ex IU 10161] (2), 57618 [ex IU 10160] (1); FMNH 52634 [ex IU] (1); ZMB 17010-11 and 13 (2, 1, 1), 23604 (2). •Valid as Ctenobrycon alleni (Eigenmann & McAtee 1907) -- (Britski et al. 1999:36 [ref. 24147], Benine & Cassati in Reis et al. 2003:126 [ref. 27061], López et al. 2003:25 [ref. 27366], Menni 2004:77 [ref. 28131], Benine et al. 2010:59 [ref. 31067], Sarmiento et al. 2014:184 [ref. 35004], Bertaco et al. 2016:413 [ref. 34561] as cf. alleni). •Valid as Astyanax alleni (Eigenmann & McAtee 1907) -- (Azpelicueta et al. 2002:1052 [ref. 26511], Azpelicueta et al. 2002:258 [ref. 26608], Almirón et al. 2002:8 [ref. 26720], Casciotta et al. 2003:332 [ref. 27401], Mirande et al. 2004:220 [ref. 27659], Mirande & Koerber 2015:23 [ref. 35117], Koerber et al. 2017:36 [ref. 35267]). •Valid as Psalidodon -- (Melo et al. 2024:30 [ref. 41541] in Acestrorhamphinae). Current status: Valid as Psalidodon alleni (Eigenmann & McAtee 1907). Acestrorhamphidae: Acestrorhamphinae. Distribution: South America: Paraguay River basin, Argentina, Brazil, Bolivia and Paraguay. Habitat: freshwater.