A new species of characid fish of the genus Nematobrycon from the Rio Calima of Colombia (Pisces, Characoidei, Characidae)

The systematic status of three nominal forms of the Colombian characid genus Nematobrycon is herein treated. All forms are illustrated and their interrelationships discussed. One species, Nematobrycon lacortei is described as new. Nematobrycon palmeri Eigenmann, a species from the northern headwaters of the Rio San Juan is compared with Nematobrycon amphiloxus Eigenmann & Wilson from the adjacent headwaters of the Rio Atrato. It is suggested that N. amphiloxus is probably a subspecies of N. palmeri. N. lacortei from the headwaters of the Rio Calima, a large southern tributary of the Rio San Juan, is considered specifically distinct from N. palmeri at the present time. Judgement on the systematic status of all forms of Nematobrycon must await collection of population samples from the headwaters of many uncollected tributaries of the Rio San Juan and Rio Atrato. Finally, forms of Nematobrycon being bred and/or imported by aquarists in the United States are identified.