A new species of characid, Hyphessobrycon hamatus, is described from the upper rio Tocantins, Goiás, Brazil. The new species is distinguished from all other Hyphessobrycon species by the presence of bony hooks on dorsal, anal, pelvic, and pectoral fins of males, the two black humeral spots, the 4 or 5 teeth in the inner series of the premaxilla, a maxilla with 2-3 teeth, the iii-v, 16-18 anal-fin rays, and a lateral line with 10-32 perforated scales and 33-35 scales in a longitudinal series.
Neotropical; Hyphessobrycon balbus; taxonomy; systematics
