A habitat specific survey of the epifauna and fish fauna of sandbanks off the Welsh coastline was undertaken in 2001. Of these, three sandbanks were considered to represent extensions of shallow nearshore soft-sediment communities, while a further six sandbanks were considered to be distinct sandbanks; seabed features clearly defined in comparison with surrounding sediments. Multivariate community analyses revealed that the distinct sandbanks had both fish and epifaunal assemblages that were distinct from those sandbanks considered to be extensions of nearshore sediments. The distinct sandbanks were typified by low species diversity and shared indicator species such as the weever fish Echiichthys vipera, the shrimp Philocheras trispinosus and the hermit crab Pagurus bernhardus. Differences occurred in species composition among the distinct sandbanks, in particular, southern sandbanks were typified by sand sole Solea lascaris and small-eyed ray Raja microocellata. The sandbanks considered as extensions of nearshore sediments shared many similarities with the Pleuronectes platessa-Limanda limanda assemblage, identified by Ellis et al. (Estuar. Coastal Shelf Sci. 51 (2000) 299), which is widespread in the Irish Sea. Sandbanks, as a habitat definition under the EU habitats directive, are likely to incorporate a number of physically and biologically distinct habitats of which two have been described in the present study.

Soft sedimentary biotopes are extensive in the shallow Western Indian Ocean, especially on the Seychelles Plateau and Mascarene Ridge, yet pro rata compared with coral reefs the research effort devoted to them has been minimal. In this study we examine the benthic mollusc and polychaete worm assemblages of the shallow waters (11-62 m) around Mahe, in the Seychelles, and make direct comparisons with the temperate Irish Sea area and subtropical waters of Hong Kong, China (using identical methodology). Two assemblages were recognized, characterized by depth and sediment type. Of these, assemblage A (in shallow carbonate sands) was the most diverse, with diversity and richness measures exceeding those from the Irish Sea or Hong Kong. Hong Kong generally had the poorest fauna. Considering the Bivalvia alone, estimates of taxonomic distinctness showed this to be least for Seychelles assemblage A. The degree of conformity of the results to the concept of the latitudinal gradient in species richness and the possible underlying causes are discussed. Comparisons with other data suggest that the Seychelles support a benthic fauna at least as diverse as any other described from the tropics. A tentative examination of total bivalve species richness suggests a total of 400-500 for the Seychelles. This is in keeping with other Indian Ocean localities, but higher than known figures for continental east Africa. The findings of this paper support the case for widespread ecological and taxonomic studies of the Western Indian Ocean benthic invertebrates.

A neotype of Amphitrite Müller (1771) is established and re-described, using material collected in 2001 from near the type locality on the southwest coast of Iceland. We examined material from Iceland, Nova Scotia and Newfoundland, identified as Pseudopotamilla reniformis, showing scissiparity and commonly found in aggregations within kelp holdfasts or amongst encrusting fauna. By contrast, scissiparity has not been seen in a population recorded as P. reniformis from Wales (broadcast spawning is presumed, Chughtai & Knight-Jones 1988), which bores into limestone and that the present analysis shows to belong to a different species from P. reniformis. Sabella oculata Krøyer (1856, Norway) is a junior synonym of P. reniformis. Sabella aspersa Krøyer (1856, Greenland) and Sabella saxicava (Quatrefages, 1866, France) are re-instated and re-described in Pseudopotamilla. Pseudopotamilla saxicava (= Potamilla ehlersi Gravier, 1906) has a widespread distribution from Britain to the Arabian Gulf, Pseudopotamilla aspersa is found in Greenland and the distribution of P. reniformis is reduced to Iceland, northern Norway, Nova Scotia and Newfoundland. The genera Eudistylia Bush and Schizobranchia Bush are discussed in relation to Pseudopotamilla.

A new species of Uncispio Green, 1982 is described from a boulder clay habitat in the southern Irish Sea. Uncispio reesi n. sp. can be separated from Uncispio hartmanae Green, 1982 by the size and shape of the occipital antenna, the arrangement of the posterior parapodial lobes, the number of anal lobes and the position and shape of thickened anterior neuropodial chaetae. The other two species of Uncispionidae, Uncispio hartmanae and Uncopherusa bifida, are reexamined and their descriptions expanded. The family status of Uncispionidae is discussed with respect to the other families in Spionida.

Two new species of Diplocirrus Haase, 1915 are described from the southern Irish Sea and South Africa. Diplocirrus stopbowitzi sp. nov., identified from several surveys around the Irish Sea in recent years, favors coarser sediments than D. glaucus (Malmgren, 1867), the only other species of Diplocirrus identified from the area. It is morphologically closest to D. capensis Day, 1961 from South Africa, due to a combination of characters (multiarticulated, hooked neurochaetae, cephalic cage absent) that have previously been considered unique to D. capensis within the genus. The other new species, D. incognitus, is described from material identified by Day as D. capensis and deposited in the Natural History Museum, London. In appearance, it approaches D. glaucus but differs most noticeably in the relative size of adherent sediment particles and in the length of papillae clustered around the notochaetae. The two new species exhibit characters that bridge the gap between D. capensis, previously considered anomalous, and the other members of the genus. The significance of hooked neurochaetae is discussed following the discovery of such chaetae on specimens of D. glaucus and D. hirsutus. Diplocirrus glaucus, D. capensis, and the two new species each possess the same two branchial forms: stout, cuneiform with longitudinal ciliated ridges and cirriform with transverse ciliated rings. Comparisons are also made with the morphologically similar genera Bradiella Rullier, 1965 and Diversibranchius Buzhinskaja, 1994.

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The new speciesAbarenicola wellsin. sp. from the Falkland Islands is described along with a re-description ofAbarenicola breviorn. stat. with which it had previously been confused. The two species are distinguished using both morphological and molecular techniques, new characters are described and previously recognized characters are clarified, all of which support the assignment of species status as opposed to subspecies. Both species are part of theAbarenicola assimilis‘group’ within which all taxa were originally described as subspecies. The group as a whole is re-evaluated and all members are elevated from subspecies to species status based mainly on the new characters of shape, distribution and pigmentation of the proboscidial papillae. The group now consists of six species:Abarenicola assimilisn. stat.,A. breviorn. stat.,Abarenicola devian. stat.,Abarenicola haswellin. stat.,Abarenicola insularumn. stat. andA. wellsin. sp.

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