new species:
Hyphessobrycon auca Almirón, Casciotta, Bechara & Ruiz Diaz, 2004

published in:
Almirón, A.E., J.R. Casciotta, J.A. Bechara. & F.J. Ruiz Diaz (2004):
A new species of Hyphessobrycon (Characiformes, Characidae) from the Esteros del Iberá wetlands, Argentina.
Revue Suisse de Zoologie 673-682

abstract (from publication):
Hyphessobrycon auca sp.n. is described from the Esteros del Iberá wetlands. Hyphessobrycon auca differs from the remaining species of the genus by the presence of one maxillary tooth with 5 cusps; dentary low with teeth decreasing in size anteroposteriorly; males with hooks in all fins; mature females with hooks on pelvic-fin rays; one humeral spot vertically elongated, bounded by a light area; a second lateral spot may be faint or well developed; a wide lateral band ending in a conspicuous caudal spot.