Two new species of the ornamental loricariid genus Baryancistrus (Siluriformes: Hypostominae) from rio Trombetas basin, Pará, Brazil

Abstract

Two new species of Baryancistrus are described from the rio Trombetas basin. These new species were collected in the late 1980’s and were analyzed morphologically and compared to the eight currently assigned species of Baryancistrus. Both new species are distinguished from their congeners by a set of non-unique characters, such as coloration, extension of dorsal-fin membrane, abdominal covering, number of mandibular teeth and size of fins. These new species are only registered for strong-energy and clear waters, powerful cataracts, with rocky substrates, being sometimes, syntopic. The patterns of distribution and morphological features among all Baryancistrus species are discussed, and an identification key is presented. Despite of occurring in a protected area, previous studies on hydroelectric plants for the rio Trombetas, as the Hydropower Plant of Cachoeira Porteira, are being re-examined by current authorities, raising deep concerns on the future conservation of the unique biodiversity of the rio Trombetas basin.