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Benthic samples collected along the Brazilian central continental margin from Espírito Santo State to Rio de Janeiro State (19° S to 24° S) during the last 20 years and at depths of 50–2200 m yielded the description of six new species of Typhlotanais in the deep-sea (> 200 m): Typhlotanais andradeorum sp. nov., T. bolarticulus sp. nov., T. ischnochela sp. nov., T. longiseta sp. nov., T. priscilae sp. nov. and T. spinibasis sp. nov. Within these species, we found members of four Typhlotanais morpho-groups as ‘cornutus’ group, ‘greenwichensis’ group, ‘spinicauda’ and ‘trispinosus’ group. Typhlotanais ischnochela sp. nov. exhibited the greatest bathymetric range, occurring from the continental shelf until the lower slope (46–1898.7 m depth). The bathymetric distribution of the other five species of Typhlotanais herein described were restricted to the slope. Tables of diagnostic characters of the Typhlotanais morpho-groups and an identification key to the species of Typhlotanaidae found in Brazil are provided. This work brings the total number of Tanaidacea known for Brazilian coast to 64 species, and the family Typhlotanaidae from Brazil is now represented by 11 species in five known genera.
Climate change is influencing some environmental variables in the Southern Ocean (SO) and this will have an effect on the marine biodiversity. Peracarid crustaceans are one of the dominant and most species-rich groups of the SO benthos. To date, our knowledge on the influence of environmental variables in shaping abundance and species composition in the SO’s peracarid assemblages is limited, and with regard to ice coverage it is unknown. The aim of our study was to assess the influence of sea ice coverage, chlorophyll-a, and phytoplankton concentrations on abundance, distribution and assemblage structure of peracarids. In addition, the influence of other physical parameters on peracarid abundance was assessed, including depth, temperature, salinity, sediment type, current velocity, oxygen, iron, nitrate, silicate and phosphate. Peracarids were sampled with an epibenthic sledge (EBS) in different areas of the Atlantic sector of the SO and in the Weddell Sea. Sampling areas were characterized by different regimes of ice coverage (the ice free South Orkney Islands, the seasonally ice-covered Filchner Trough and the Eastern Antarctic Peninsula including the Prince Gustav Channel which was formerly covered by a perennial ice shelf). In total 64766 individuals of peracarids were collected and identified to order level including five orders: Amphipoda, Cumacea, Isopoda, Mysidacea, and Tanaidacea. Amphipoda was the most abundant taxon, representing 32% of the overall abundances, followed by Cumacea (31%), Isopoda (29%), Mysidacea (4%), and Tanaidacea (4%). The Filchner Trough had the highest abundance of peracarids, while the South Orkney Islands showed the lowest abundance compared to other areas. Ice coverage was the main environmental driver shaping the abundance pattern and assemblage structure of peracarids and the latter were positively correlated with ice coverage and chlorophyll-a concentration. We propose that the positive correlation between sea ice and peracarid abundances is likely due to phytoplankton blooms triggered by seasonal sea ice melting, which might increase the food availability for benthos. Variations in ice coverage extent and seasonality due to climate change would strongly influence the abundance and assemblage structure of benthic peracarids.
This paper describes a novel species of the genus Heterophoxus Shoemaker, 1925 from Brazil. The material examined was collected during the Mini Biological Trawl Project, off southeast and southern Brazil's coast off the states of Rio de Janeiro, Santa Catarina, and Rio Grande do Sul, ranging in depth from 25 to 128 meters. The new species, H. shoemakeri sp. nov., is similar to H. videns K.H. Barnard, 1930; however, the former species can be distinguished by: pereopod 7 basis posterior margin serrate with acute teeth, merus posterior margin not produced; epimeral plate 3 posteroventral corner with a longer acute projection, posterior margin almost straight; uropod 3 outer ramus article 2 clearly notable in both sexes. For Brazilian waters, this is the second record of the genus and the first species described with type material from the country. Besides that, we provide an identification key for the world species of Heterophoxus and a distribution map for the new species.
During a recent investigation of the benthic macrofauna from coastal lagoons of southern Benin (Ahémé, Nokoué and Porto-Novo lagoons), a new species of the amphipod genus Quadrivisio Stebbing, 1907, Q. laleyei sp. nov. was collected by means of different quantitative and non-quantitative methods (plastic baskets, wooden artificial substrates, uprooted plants and Surber net) in their intertidal macrophyte zone. The new species can be easily distinguished from most of the other species of the genus by the setation of the mandibular palp and telson and a reduced number of articles (4–6) on the accessory flagellum of the first antenna. The new species closely resembles to Q. lutzi (Shoemaker, 1933) but clearly differ by a reduced armature of the urosomites 1 and 2 and by the geographical distribution (Q. lutzi being known only in Central and South America). Ecological data and an updated key to a species in the genus Quadrivisio are provided.