Sphaerodoridae (Annelida: Polychaeta) from the Bellingshausen Sea (Antarctica) with the description of two new species

The examination of polychaete collections obtained during the Spanish Bentart 2006expedition to the Bellingshausen Sea (Antarctica) revealed the presence of several sphaerodorid species. In this work, species belonging to the genera Sphaerodorum Örsted, 1843, Ephesiella Chamberlin, 1919, Clavodorum Hartman and Fauchald, 1971 and Sphaerephesia Fauchald, 1972 are reported including two new species belonging to Sphaerodorum and Sphaerephesia, respectively. A specimen identified as Ephesiella sp. might also represent a new species but, due to its poor state of preservation, a formal description is not possible yet. Furthermore, Sphaerodoropsis polypapillata Hartmann-Schröder and Rosenfeldt, 1988 is transferred to the genus Clavodorum Hartman and Fauchald, 1971 after examination of the type series and specimens obtained from the Bellingshausen Sea.Comisión Interministerial de Ciencia y Tecnología; REN 2001-1074/ANTComisión Interministerial de Ciencia y Tecnología; CGL2004-0185

Epibenthic diversity in the North Sea

In 1999 the epibenthic fauna of the North Sea was investigated using the 3rd quarter 'International Bottom Trawl Survey' of five European countries. Altogether 241 stations were sampled covering 143 ICES rectangles. The objectives of the projects were (i) to analyse epibenthic diversity patterns in the North Sea, (ii) to identify the spatial distribution of faunal communities and (iii) to relate environmental factors as well as fishing effort to species diversity. Epibenthic fauna was clearly divided between the southern North Sea and the central-northern North Sea, roughly along the 50 m depth line. The separation was based on an overall higher number of species in the central and northern North Sea and a change in the species composition from north to south. Sessile fauna including erect, branching species like bryozoans and hydrozoans were particularly diverse along a corridor in the central-northern North Sea between 56° and 58°N, coinciding with the area between the 50 m and 100 m depth line. Cluster analysis, based on the structure of the community, confirmed the north-south gradient found for species diversity. Separation of clusters was driven to a great extent by species occurring predominantly or exclusively north of the 50 m contour line. Few species were exclusive to the south, but a number of scavenging species were found here more frequently and in higher numbers. Depth was positively correlated with the diversity of free-living fauna, whereas the type of sediment showed no significant relationship with variations in numbers of species. Beam-trawling effort was negatively correlated with the diversity of sessile fauna