arnoldi, Myloplus Ahl [E.] 1936:25 [Zoologischer Anzeiger v. 114 (nos 1/2); ref. 13683] Amazon River. Syntypes: (2) ZMB 20812 (now 1). Types mentioned: Paepke 1995:92 [ref. 21847]. •Valid as Myleus arnoldi (Ahl 1936) -- (Jégu in Reis et al. 2003:185 [ref. 27061]). •Valid as Myloplus arnoldi Ahl 1936 -- (Jégu 2001:386 [ref. 25923], Jégu et al. 2003:850 [ref. 27668], Andrade et al. 2016:154 [ref. 34307], Andrade et al. 2016:579 [ref. 34960], Andrade et al. 2018:120 [ref. 35868], Andrade et al. 2019:[8] [ref. 37167], Ota et al. 2024:412 [ref. 40817]). Current status: Valid as Myloplus arnoldi Ahl 1936. Serrasalmidae: Myleinae. Distribution: Amazon, Xingu and Tocantins River basins, Brazil. Habitat: freshwater.