A review of the Cis-Andean species of Hemibrycon Gunther (Teleostei: Characiformes: Characidae: Stevardiinae), with description of two new species

The species of Hemibrycon occurring in the east of the Andean Cordilleras are reviewed based on their type series and additional specimens. Nine species are redescribed: H. beni from rio Beni basin, Bolivia; H. helleri from the upper rio Ucayali, Peru; H. huambonicus from the rios Huallaga and Maranon basins, Peru; H. jeslkii from the upper portions of rios Maranon, Ucayali and Madeira basins, Bolivia, Brazil, and Peru; H. metae from rio Orinoco basin, Colombia and Venezuela, and Caribbean coastal basins of Venezuela; H. polyodon (type species) from rio Pastaza basin, Ecuador; H. surinamensis from coastal basins of French Guiana and Suriname, and from lower rios Tapajos, Tocantins and Xingu basins, Brazil; H. taeniurus from river basins from Trinidad Island, Trinidad and Tobago, and H. tridens from upper rio Ucayali basin, Peru. Two new species are described: H. inambari from the upper rio Madre de Dios basin, Peru and H. mikrostiktos from rio Ucayali basin, Peru. These species are distinguished among themselves mainly by the color pattern, and meristic characters. The distribution area of the genus is enlarged reaching the lower Tapajos, Tocantins and Xingu river basins, Brazil, with the first record of the occurrence of H. surinamensis in this country. A new description and diagnosis is provided for the type species of the genus, regardless its recent redescription. The type series of H. helleri that was previously considered dubious is found and described. Hemibrycon coxeyi and H. pautensis are considered junior synonyms of H. polyodon. Tetragonopterus (Hemibrycon) trinitatis, previously considered species inquirenda in Characidae, and Hemibrycon guppyi are junior synonyms of H. taeniurus. Hemibrycon orcesi is transferred to Boehlkea. A taxonomic key for the species of the genus to the east of the Andean Cordilleras is presented.