Four species of Pisionidae (Polychaeta) are reported from Coiba National Park (Pacific, Panamá), one is a well known species of the area Pisionidens indica, one is a new species of Pisione and there are two new reports: Pisione galapagoensis and Pisione cf. papuensis. Pisione longispinulata sp. nov. possesses buccal aciculae distally elongated with a conspicuous notch, three compound chaetae per parapodium, with dense and long spines on margins, and a single pair of copulatory organs, each with modified ventral cirrus, distal spherical enlargement and distal papillae. The closest species is Pisione garciavaldecasasi, also from the Coiba National Park, although it lives in freshwater streams in the northern part of Coiba Island.

The diet and feeding behaviour of the burrowing shrimp Alpheusmacellarius (Decapoda: Alpheidae) in sea grass beds in the Philippines were evaluated in the present study through field and laboratory activities. Sediment organic matter and sea grass appear to be important food sources for the shrimp based on the combined results of field surveys, gut content, stable isotope (δ13C) and sediment C content analyses. There was a significant positive correlation between organic matter content in the sediment and shrimp densities. In terms of behaviour, observations under controlled set-ups detected marked trends in duration and frequency of feeding. Feeding bouts became longer and more recurrent as the days progressed. Periodicity was exhibited with burrowing generally performed in the morning and feeding in the afternoon. A deposit-feeding mode was predominant in tank conditions as demonstrated by the shrimp's behaviour and burrow features.

The identification of most soft-bodied hexacorals requires morphological and histological examinations of preserved specimens and experience for correct interpretation of the observed features. Poorly preserved or damaged material resulting from improper sampling complicates identification. In many cases the characteristics of the preserved specimens alone do not lead to satisfying results. Living specimens, however, exhibit numerous characteristics which would often allow identification, even in the field. However, most of these characteristics get lost during preservation. Modern techniques and advances in sampling methods allow the acquisition and preservation of a lot of information on the living animal and its habitat.

Using Chilean sea anemone species, it is demonstrated how the work with specimens in situ and in vivo can help with identification and reveal important morphological–taxonomical, biological, and ecological information. Whenever possible, this information should be part of species descriptions and should be used to create detailed, reliable, tabular identification keys for the laboratory and field. The examples illustrate the urgent need for modern, comparable re-descriptions. In most parts the protocol also applies to other soft-bodied hexacorals.

There are few reports of non-cryogenic preservation methods for marine invertebrates, so potable alcohol and acetone-based nail varnish remover (NVR) are for the first time evaluated against absolute ethanol as short-term preservatives of whole barnacles. Performance of ethanol and NVR-preserved material was comparable, but potable alcohol was significantly worse. These results are of practical importance for fieldwork in remote areas where laboratory chemicals are unattainable but potable alcohol or NVR are locally available. Of these, acetone-based NVR would be the solvent of preference.

Munida subrugosa is the most abundant galatheid crab species in the Beagle Channel (55°S 68°W) off Tierra del Fuego, Argentina. Samples of crabs and the epibenthic community were taken on a monthly basis at two different depth strata (<40 m and >70 m), by means of epibenthic trawling from 1998 to 1999. Stomach contents from 1582 crabs were analysed, out of which only 2% had empty stomachs. The quantity of food in the stomach contents was clearly seasonal and similar at both depths. The organic matter varied throughout the year and between both depths, being significantly higher in summer/spring than in autumn/winter. Munida subrugosa shows two different and simultaneous feeding habits: (1) as a predator M. subrugosa feeds on crustaceans, algae, and polychaetes; and (2) as a deposit feeder M. subrugosa consumes particulate organic matter and organisms associated with the superficial layer of the sediment. The composition of the diet of Munida subrugosa was similar for both years, and independent of depth, sex or season. Munida subrugosa selected crustaceans only in autumn and winter, whereas most food items were found according to their availability in the habitat.

Fourteen rare or poorly known sponge species have been found in the Aegean Sea. The species Pachastrissa pathologica, Calthropella stelligera, Weberella verrucosa, Aaptos papillatus, Timea geministellata, Spiroxya heteroclita, Clathria translata, Hymedesmia simillima, Mycale serrulata, Myrmekioderma spelaea, Callyspongia septimaniensis and Ircinia pipetta are new records for the eastern Mediterranean while the species Geodia barretti and Petrosia vansoesti are reported for the first time from the Mediterranean Sea. Information on their morphology, geographical and bathymetrical distribution is given and discussed.

The discovery of the association between the sponge Desmapsamma anchorata (Demospongiae: Poecilosclerida: Desmacididae) and the octocoral Carijoa riisei (Cnidaria: Alcyonacea: Clavularidae) on an Indonesian reef enlarges the widespread dispersion of these Atlantic species in the Indo-Pacific area. The species involved and their morphological adaptations resulting from the association are described. When covered by the sponge, C. riisei develops an irregular branching pattern and a dense nematocyst layer where the ectoderm comes in contact with the sponge tissue. The finding of fertile colonies suggests that the Indonesian population of C. riisei is self-sustaining.

Males of the hermit crab Pagurus filholi show pre-copulatory mate guarding behaviour to keep a receptive female from other rival males during the breeding season. Guarding males are often replaced by other males via contest competition. Shell size fit and shell species of males effects were investigated to see if their ability to defend females against rivals depends on their shell. Shell size fit and shell species of guarding males were experimentally manipulated and then, the males were allowed to guard a female and interact with rival males of various sizes. Contest outcomes depended on neither the shell size fit nor shell species of the guarding males, and depended on body size ratio between guarding and rival males. When the body size of guarding and rival males was similar, however, guarding males in large fitting shells defended their female mate significantly more often than those in small fitting shells. For Chlorostoma lischkei shells, small males preferred larger shells during the breeding season than after the breeding season. The plasticity in the shell size preference of small males suggests that they compensate for body size disadvantage in mating versus larger rivals and for higher defence ability of female mates versus similar sized rivals.

The predatory effects of Pachygrapsus marmoratus on populations of the intertidal limpet Patella depressa were analysed on rocky shores located on the central coast of Portugal. Nocturnal observations on crab feeding behaviour were conducted and experimental exclusion cages were set in the substratum to assess density effects on limpets. The results indicated that although crabs feed on adult limpets the predatory level was minimal. Crabs used consistent tactics to detach limpets from the substratum but the majority of the attacks were unsuccessful, possibly due to morphological and behavioural adaptations of limpets. An alternative recruitment hypothesis is advanced to explain non-significant differences between experimental treatments and a possible predatory role on shaping levels of recruitment on lower levels of the shore is considered.

Three colonies of warm-water coral Astroides calycularis were found at the eastern part of the middle Adriatic Sea during the 1990–2001 period. For each specimen, depth distribution and habitat were recorded. Previous and recent knowledge of this species in the Adriatic Sea and in the Mediterranean Sea was discussed in relation to climatic changes. Occurrence of A. calycularis in the Adriatic Sea was related to the increased temperatures of the surface marine layer. Variable temperature conditions were connected to the climatic changes on the hemispheric scale through the North Atlantic Oscillation index. The prevailing sea current system together with the coastal configuration and bottom type favours the presence of the studied warm-water coral on the eastern Adriatic coast.

Lumbricalus is redefined and revised. Its diagnostic features are chaetae of four types: composite spinigers, composite multidentate hooded hooks, simple multidentate hooded hooks, and limbate chaetae; the maxillary apparatus is labidognath with five pairs of maxillae, maxillae II are shorter than maxillae I with a wide connecting plate along the base of maxillae II. Lumbricalus, as redefined herein, includes L. januarii (type species), L. adriatica, L. composita, L. aotearoae, L. foresti stat. nov., L. harrisae sp. nov., L. vivianneae sp. nov., and L. vossae sp. nov. A key to all species is included.

Feeding dynamics of Cancer polyodon was studied, by comparing the diets of three size-classes of the crab to environmental abundance of prey species in three habitats in Tongoy Bay, Chile (30°S). In the sea grass and sand–gravel habitats cannibalism was observed, the small C. polydon being actively selected as the main prey in spite of their lower abundance compared with other crustaceans. In the mud habitat the scallop Argopecten purpuratus was the most important prey, being actively selected although occurring at low relative abundance. Cancer polyodon showed plasticity in feeding habits, adapting to differential prey availability, but always selecting certain species independently of their abundance in each habitat. Accessibility, more than the abundance of the prey, seem to be the main factors influencing prey selection.

The populations of three sympatric hermit crabs, Pagurus excavatus, Anapagurus alboranensis and Anapagurus petiti were studied in a shallow (15–25 m) sandy area in the north-western Mediterranean. Seasonal abundance, seasonal size frequency, sex ratio and reproductive periods were examined. Pagurus excavatus was the largest and most abundant species in the zone. Pagarus excavatus and Anapagarus alboranensis are sexually dimorphic in relation to size, with males reaching larger sizes than females. However, the males and females of Anapagurus petiti reach similar large sizes. Anapagurus petiti has a sex ratio that is female biased, whereas A. alboranensis and P. excavatus are 1:1. Anapagurus petiti showed a higher reproductive activity during warmer seasons, while in A. alboranensis the proportion of ovigerous females was high throughout the year, with a minimum in autumn. The activity and clutch size of P. excavatus decreased during summer.

The hypothesis investigated in this paper is that the interstitial polychaete Saccocirrus sonomacus is excluded from beaches impacted by tailing disposal as a result of the blocking of the interstitial space and not by a response to the toxicity of elevated copper concentrations. Field evidence suggested that abundances of S. sonomacus on beaches where they would be expected to occur under natural conditions are lower when a beach has received a significant amount of tailings. In choice experiments, S. sonomacus always preferred an open coarse sand matrix to one where the interstitial spaces had been blocked by fine sand (a tailings substitute). Using invitro bioassays, we found that the LC50 for S. sonomacus with copper was 44 μg Cu l−1, this being higher than the values of interstitial labile copper measured on the beaches investigated in this study. We therefore accept the hypothesis of a physically mediated exclusion rather than a toxically mediated one.

Four new species belonging to the families Eunicidae and Onuphidae are described on the basis of specimens collected from El Salvador, Central America. Additionally ten species belonging to Onuphidae are mentioned, nine of these are newly reported from El Salvador. Eunice chicasi sp. nov., belong to the group of species with acicula distally hammer head, peristomial cirri smooth only reaching middle peristomium, branchiae from chaetiger 5 to the end of body, with up to six filaments, falcigers with lateral tooth triangular, well developed. Eunice salvadorensis sp. nov. has moniliform and cylindrical articles in the antennae, peristomial cirri with 17 small moniliform articles. Kinbergonuphis kristiani sp. nov. presents up to ten branchial filaments, ventral cirri digitiform on the first seven chaetigers, pseudocompound hooks tridentate appear on chaetigers 1–5, large tridentate hooks on chaetigers 5–7, and subacicular hooks from chaetiger 19. Paradiopatra barrazai sp. nov. belongs to the group of species with inner lateral antennae longer than the median antennae, ceratophores with four rings, ventral cirri of chaetigers 1–2 cirriform, postchaetal lobe digitate visible to the end of the body, tridentate pseudocompound hooks on chaetigers 1–4, large tridentate hook on chaetigers 5–28, subacicular hooks from chaetiger 30.

The function of intersex individuals in three intertidal hermit crab species (Clibanarius antillensis, C. sclopetarius, and C. vittatus) was investigated and a description of the morphology of the gonopores of laboratory-reared intersex individuals before and after moulting provided. Observations on the reproductive behaviour revealed that intersex individuals of these hermit crab species copulated successfully as males with normal females. Intersex individuals showed morphological alterations indicating closure of the female gonopores after moulting. These findings associated to information on behaviour and population biology of hermit crabs may suggest that hermit crab intersexuality may be part of a true hermaphroditism mechanism.

In a field experiment, the accumulation of trematode (Echinostomatidae) metacercariae by the New Zealand cockle Austrovenus stutchburyi was compared among treatments with different seabed hydrodynamics and sedimentation rates. There was no significant difference among the treatments in the rate at which cockles accumulated metacercariae, suggesting that infection rates are not influenced by water flow conditions within the normal range experienced in natural habitats. There was, however, substantial spatial variation in infection rates among the experimental plots. This result indicates that metacercarial accumulation varies horizontally as well as vertically within the intertidal zone.

Distichopora robusta, the first shallow-water stylasterid coral from the tropical eastern Pacific, is described from the west coast of Panama. The new species is distinguished from all species of Distichopora described thus far by having robust branches and poorly defined pore rows.

Multiple locus allozyme heterozygosity has been shown to be weakly, but significantly correlated with certain fitness parameters in bivalves. Immune function of individual Mytilus edulis from the Menai Strait, Wales, UK was assessed monthly over one year (1997–1998) by measuring total blood cell (haemocyte) counts, differential haemocyte counts (% basophils and eosinophils), phagocytic capability (by zymozan uptake) and intracellular superoxide generation. Sampled mussels were also scored at 9 allozyme loci. Mussels were then grouped into multiple locus heterozygosity (MLH) classes and plotted separately against the different measures of immunocompetence. No significant association was present between MLH and total haemocyte count, phagocytic capability or intracellular superoxide generation. However, there was a significant association between MLH and the character (basophilic or eosinophilic) of circulating haemocytes (r2=0·057, P=0·002). Highly heterozygous individuals tended to have significantly more eosinophilic haemocytes circulating in the blood than highly homozygous individuals. Eosinophilic haemocytes are known to have a high capacity for phagocytosis of invading organisms and these results may therefore be interpreted as increased health (=fitness) in more highly heterozygous individuals.

The epibiotic iron-encrusted biofilms occurring on the shell of the bivalve Montacuta ferruginosa were examined over an annual cycle in order to determine possible variation of the iron-encrustation. Among the 379 examined specimens, well-coated bivalves always predominate. However, it was found that about 50% of the small-sized bivalves were uncoated or weakly coated during the summer months. This result can be explained by the life history of the bivalve and by the physico-chemical conditions in the sediments.