Benthic biogeographic patterns on the deep Brazilian margin.

The Brazilian continental margin (BCM) extends from the Tropical to the Subtropical Atlantic Ocean, with much of its seafloor within deep waters, supporting rich geomorphological features and under wide productivity gradients. Deep-sea biogeographic boundaries on the BCM have been limited to studies that used water mass and salinity properties of deep-water masses, partly as a result of historical under sampling and a lack of consolidation of available biological and ecological datasets. The aim of this study was to consolidate benthic assemblage datasets and test current oceanographic biogeographical deep-sea boundaries (200-5,000 m) using available faunal distributions. We retrieved over 4,000 benthic data records from open-access databases and used cluster analysis to examine assemblage distributions against the deep-sea biogeographical classification scheme from Watling et al. (2013). Starting from the assumption that vertical and horizontal distribution patterns can vary regionally, we test other schemes incorporating latitudinal and water masses stratification within the Brazilian margin. As expected, the classification scheme based on benthic biodiversity is in overall agreement with the general boundaries proposed by Watling et al. (2013). However, our analysis allowed much refinement in the former boundaries, and here we propose the use of two biogeographic realms, two provinces and seven bathyal ecoregions (200-3,500 m), and three abyssal provinces (>3,500 m) along the BCM. The main driver for these units seems to be latitudinal gradients as well as water mass characteristics such as temperature. Our study provides a significant improvement of benthic biogeographic ranges along the Brazilian continental margin allowing a more detailed recognition of its biodiversity and ecological value, and also supports the needed spatial management for industrial activities occurring in its deep waters.

A new deep-sea species of Barathronus Goode & Bean from Brazil, with notes on Barathronus bicolor Goode & Bean (Ophidiiformes: Aphyonidae)

A new species of Barathronus (Ophidiiformes: Aphyonidae) is described from a single, mature male specimen (101 mm SL) bottom trawled on the continental slope of Rio Grande do Norte, northeastern Brazil, between 1,964 and 2,045 m depth. The new species is diagnosed among congeners by the following combination of characters: peritoneum transparent, deep-set eyes not visible, eight fangs on vomer, anal fin rays 69, predorsal length 42.0% SL, preanal length 49.5% SL, penis long, slender, and lacking a pair of lobes at its base, and presence of a ventral flexure of the anterior 2-3 vertebrae. Additionally, morphological data of three specimens of Barathronus bicolor collected in Brazilian waters are presented and compared with those from 51 specimens from the western Central Atlantic.

Uma nova espécie de Barathronus (Ophidiiformes: Aphyonidae) é descrita a partir de um único exemplar macho (101 mm CP) coletado com arrasto de fundo no talude continental do Rio Grande do Norte, nordeste do Brasil, entre 1.964 e 2.045 m de profundidade. A espécie nova é diagnosticada entre as congêneres pela seguinte combinação de caracteres: peritônio transparente, olhos alojados profundamente e não distinguíveis, oito presas no vômer, nadadeira anal com 69 raios, comprimento pré-dorsal 42,0% CP, comprimento pré-anal 49,5% CP, pênis longo, afilado e sem um par de lobos em sua base, e presença de flexão ventral nas 2-3 vértebras anteriores. Adicionalmente, dados morfológicos dos três espécimes de Barathronus bicolor coletados em águas brasileiras são apresentados e comparados com aqueles de 51 espécimes do Atlântico Central ocidental.