https://doi.org/10.1643/i2023058
https://bioone.org/journals/ichthyology ... 3058.short
We report the first record of a species of Pareiorhaphis in the Manhuaçu River basin, an affluent to the right bank of the middle Doce River drainage in eastern Brazil. The description is based on a series of specimens recently collected and also on historical samples. All specimens were obtained from habitats with very strong water current running over flat bedrock. The new species is readily diagnosed from congeners by features related to the distinct morphology of lower lip papillae, unique pattern of plates covering the pectoral girdle between insertions of pectoral fins, and the lack of a maxillary barbel. In addition, the combination of longer snout, smaller orbital diameter, shape of the pectoral-fin spine, low number of dentary teeth, and lack of a dorsal-fin spinelet also distinguishes the new species from all species of Pareiorhaphis. The new species is further compared to Pareiorhaphis nasuta, P. scutula, P. proskynita, and P. vetula, congeners from the Doce River basin, and hypothesized to have traits that represent important adaptations for living in torrential habitats.
Apresentamos o primeiro registro de uma espe´cie de Pareiorhaphis na bacia do rio Manhuaçu, afluente da margem direita do me´dio Rio Doce, no leste do Brasil. A descric¸ a˜o baseia-se numa s ´rie de espe´cimes recentemente recolhidos e tambe´m em amostras antigas. Ambas as amostras foram obtidas de habitats com correntes de a´gua muito fortes correndo sobre leito rochoso plano e sem pedras soltas. A nova espe´cie e´ prontamente diagnosticada de seus congeˆneres por caracterı´sticas relacionadas a` morfologia distinta das papilas do la´bio inferior, padra˜o u´nico de placas cobrindo a cintura peitoral entre as inserc¸o˜es das nadadeiras peitorais e a auseˆncia de um barbilha˜o maxilar. Ale´m disso, a combinac¸a˜o de focinho mais longo, diaˆmetro orbital menor, forma do espinho da nadadeira peitoral, baixo nu´mero de dentes no denta´rio e auseˆncia de spinelet da nadadeira dorsal tambe´m distingue a nova espe´cie de todas as outras espe´cies de Pareiorhaphis. A nova espe´cie e´ ainda comparada com Pareiorhaphis nasuta, P. scutula, P. proskynita e P. vetula, congeˆneres da bacia do Rio Doce, e supostamente possui caracteres que representam adaptac¸a˜o importante para viver em habitats torrenciais.