Hyphessobrycon platyodus (Teleostei: Characiformes), a new species from the Rio Madeira basin, Brazil, with comments on how multicuspid teeth relate to feeding habits in Characidae.

A new species of Hyphessobrycon is described from the Rio Juma, a tributary of the lower Rio Aripuanã-Rio Madeira basin, Amazonas, Brazil. Hyphessobrycon platyodus can be distinguished from its congeners by the: presence of an elongated dorsal fin in adult males, 25-28 branched anal-fin rays and absence of dark blotches from the dorsal fin and caudal peduncle. The presence of multicuspid teeth in species of Characidae and its relation with feeding habits are briefly commented on.