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The anatomy of Cossura pygodactylata Jones, 1956 (Annelida; Cossuridae) is presented, based on the study of specimens collected during the BIOICE project in Icelandic waters and additional material from the White Sea. General gross external and internal anatomy were investigated by means of micro-computed tomography (micro-CT) and compared with results obtained with light microscopy histological sectioning (LMHS). Micro-CT revealed a highly regionalised gut, posterior to the pharyngeal cavity and oesophagus, divided in an anterior stomach and a posterior intestine with different morphologies. The stomach is in the thoracic region, dorsally positioned and divided in a short and narrow anterior part and a longer posterior one, with an increasing diameter towards its posterior end. Both stomach regions bear a dorsal infolding of tissue, along its inner wall, that resembles to the typhlosole of the Clitellata. The heart is dorsally located and contains a heart body above the hind stomach. The intestine is wider than the stomach, without dorsal infolding inside the lumen and filling most part of the internal body cavity. A transitional cup-shaped gut element connecting the stomach and the intestine could be observed at the level of the last thoracic segment. In general, the resolution of micro-CT images reflects reasonably well the main elements of gross external and internal anatomy of cossurids, and that of gut architecture in particular.

Based on specimens collected during several sampling programmes mainly in the northern North Sea, Scotland, a new species of the genus Terebellides (Polychaeta; Trichobranchidae) was found and described herein as Terebellides shetlandica spec. nov. The new species is primarily characterised by the presence of a long pointed posterior filament in the ventral branchial lobes. The species is compared with other Terebellides species described or reported from North Atlantic waters, and an updated key to the Terebellides species of the North East Atlantic and Mediterranean Sea is provided. The presence of copepods of the genus Melinnacheres attached to the thorax of this species is reported. Morphology of T. shetlandica spec. nov. was also studied with SEM and micro-CT. Branchial characters used in the taxonomy of the genus are reviewed and four general branchial types are defined.

Based on material collected during the BIOICE project off Iceland, the taxonomy and distribution of eight species of polychaetous annelids belonging to the genus Ampharete (Polychaeta: Ampharetidae) are reviewed. Five of these species were previously reported in the area: Ampharete acutifrons, Ampharete borealis, Ampharete finmarchica, Ampharete octocirrata and Ampharete petersenae; two are new to Icelandic waters: Ampharete baltica and Ampharete lindstroemi; and one is new to science: Ampharete villenai sp. nov. A. petersenae was found for the first time after the original description and is redescribed. A. villenai sp. nov. is primarily characterized by the size, shape and disposition of the paleae, a special kind of chaetae located on the first body chaetiger. Several body characters of high taxonomic relevance in Ampharetidae are reviewed under the SEM. The distribution of each species off the coast of Iceland and a key to all species recorded in European Boreo-Arctic waters is provided.

The structure and spatial distribution of the macrofauna community of the Bellingshausen Sea in the western sector of Antarctica was studied during the ‘BENTART–06’ oceanographic expedition. This is one of the least explored Antarctic seas. A total of 20 box cores were sampled at 11 stations ranging from 157 to 3,304 m depth, using an USNEL-type box corer (BC) dredge. Representatives of 25 higher taxa of invertebrates were collected. Deeper sampling sites were less rich in taxa (4–7 taxa), whereas the figures were higher at shallower sites (up to 17 taxa). Faunal density on the sea bottom revealed a horizontal spatial gradient from the western sites with extremely low figures (90 indiv./m2) towards the eastern ones with the highest figures (1,360 indiv./m2) close to the Antarctic Peninsula. Several abiotic factors (depth, redox, organic matter, carbonates and particle size of surficial sediments) were measured simultaneously on the sea floor to characterise the substrate preferences of the fauna. Positive correlations were found between the faunal distribution and a combination of depth, redox values, and organic matter content of sediments. This indicates decreasing availability of food in the deeper bottoms of the Bellingshausen Sea with a prevalence of depauperated bottoms dominated almost exclusively by a foraminiferans community., Sí

The Spanish cruise “Bentart 94” was the first of two devoted to the study of the benthic marine fauna off Livingston and Deception Islands, South Shetland Islands, Antarctica. In this paper, the taxonomic results of the examination of the “errant” families of the polychaetes collected during that cruise are presented. A total of 834 specimens have been examined, belonging to 34 species of 31 genera and 11 families. A new species, Micronereis anaramosae, is described, and Eusyllis kerguelensis McIntosh is referred to the genus Pionosyllis. The specimens were found in 109 samples of muddy sand, mud, stones, rocks, gravel, and mixed sediments, by scuba diving, Van Veen grab, rock trawl and anchor dredge.