A review of the Cis-Andean species of Hemibrycon Günther (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. As especies de Hemibrycon que ocorrem a leste das Cordilheiras dos Andes sao revisadas com base na analise do material tipo e exemplares adicionais. Nove especies sao redescritas: H. beni da bacia do rio Beni, Bolivia; H. helleri do alto rio Ucayali, Peru; H. huambonicus para as bacias dos rios Huallaga e Maranon, Peru; H. jeslkii para as porcoes superiores das bacias dos rios Maranon, Ucayali e Madeira, Bolivia, Brasil e Peru; H. metae para a bacia do rio Orinoco, Colombia e Venezuela, e bacias costeiras do Caribe na Venezuela; H. polyodon (especie-tipo) para a bacia do rio Pastaza, Equador; H. surinamensis para as bacia costeiras da Guiana Francesa e Suriname, e porcao inferior das bacias dos rios Tapajos, Tocantins e Xingu, Brasil; H. taeniurus para os rios da ilha de Trinidad, Trinidad and Tobago; H. tridens para a bacia do alto rio Ucayali, Peru. Duas especies novas sao descritas: H. inambari para a bacia do alto rio Madre de Dios, Peru e H. mikrostiktos para a bacia do rio Ucayali, Peru. Estas especies distinguem-se principalmente pelo padrao de colorido e caracteres meristicos. A area de distribuicao do genero e ampliada para as porcoes inferiores das bacias do Tapajos, Tocantins e Xingu, Brasil, com o primeiro registro de H. surinamensis para este pais. Uma nova diagnose e descricao sao fornecidas para a especie-tipo do genero, apesar de ter sido recentemente redescrita. A serie-tipo de H. helleri previamente considerada questionavel e encontrada e descrita. Hemibrycon coxeyi e H. pautensis sao considerados sinonimos juniores de H. polyodon. Tetragonopterus (Hemibrycon) trinitatis, anteriormente considerada como species inquirenda em Characidae, e Hemibrycon guppyi sao sinonimos juniores de H. taeniurus. Hemibrycon orcesi e transferida para Boehlkea. E apresentada uma chave taxonomica para as especies do genero a leste das Cordilheiras dos Andes.