altus, Acestrorhynchus Menezes [N. A.] 1969:52, 118, Fig. 38 [Arquivos de Zoologia (São Paulo) v. 18 (nos 1-2); ref. 7834] Rio Arari, at Cachoeira do Arari, Ilha de Marajó, Pará State, Brazil. Holotype: MCZ 45256. Paratypes: (57) BMNH (7); DZSASP 3527 (1), 4558-59 (2); FMNH 74360 (10); MCZ 832 (2), 20623 (2), 20625 (1), 45251 (1, c&s), 45252-55 (4), 45257-74 (18), 46003 (1), 46005-06 (2); MZUSP 2049 (1), USNM (2); ZMA 110399 (2). Type catalog: Nijssen et al. 1982:13 [ref. 19236], Menezes & Géry 1983:590 [ref. 8307], Ibarra & Stewart 1987:5 [ref. 12367], Oyakawa 1996:446 [ref. 23140]. •Synonym of Acestrorynchus pantaneiro Menezes 1990 -- (Casciotta et al. 2003:118 [ref. 28130], Menni 2004:74 [ref. 28131]). •Valid as Acestrorhynchus altus Menezes 1969 -- (Ortega & Vari 1986:7 [ref. 9708], Menezes 1992:47 [ref. 21389], Gómez & Chebez 1996:47 [ref. 23791], Britski et al. 1999:56 [ref. 24147], Lasso et al. 2001:95 [ref. 25928], Menezes in Reis et al. 2003:231 [ref. 27061], Toledo-Piza 2007:754 [ref. 29426], Sarmiento et al. 2014:183 [ref. 35004], Careaga et al. 2020:75 [ref. 37774], Meza-Vargas et al. 2021:15 [ref. 39298]). Current status: Valid as Acestrorhynchus altus Menezes 1969. Acestrorhynchidae: Acestrorhynchinae. Distribution: South America: Amazon River basin (Bolivia, Brazil and Peru). Habitat: freshwater.