The structure and distribution of the sponge community in five sites and four habitats in Cagarras Archipelago, Rio de Janeiro, Brazil, are described. The archipelago has three major islands (Cagarra, Palmas, and Comprida), and four islets. Qualitative samples were taken by SCUBA diving in the three islands and in two islets, and quantitative samples were taken in Palmas Island only. Cluster analysis using Jaccard's coefficient on qualitative data grouped the two islets (Cagarra Bank and Cagarra Islet), which are more exposed to wave action, and the three islands formed a group of relatively sheltered sites. Cluster analysis using Bray–Curtis coefficient on quantitative data from different habitats in Palmas Island allowed distinction of three groups of samples: overhangs, shallow horizontal surfaces (6 m depth), and vertical walls plus deeper horizontal surfaces (17 m depth). Sponge abundance was greater in overhangs (61·2 ind m−2), which were dominated by Protosuberites sp. and Clathrina conifera. Abundance was reduced in vertical walls (31·1 ind m−2) and deep horizontal surfaces (16·8 ind m−2). Pachychalina sp. dominated the deep horizontal surfaces and Clathrina conifera was dominant in overhangs. Values of Shannon's diversity in overhangs, vertical walls (both with H′=2·1 bits ind−1) and deep horizontal surfaces (H′=1·7 bits ind−1) were moderate and similar, whereas in shallow horizontal surfaces the sponges were both less diverse (H′=0·37) and less abundant (8·5 ind m−2). Shallow horizontal surfaces were dominated by Hymeniacidon heliophila. The reduced species richness of the sponge community in Cagarras Archipelago when compared with other sites in Brazil and elsewhere is probably due in part to the pollution from the city of Rio de Janeiro. Wave action appears to reduce the number of sponge species at a local scale, whereas substrate inclination affects more strongly the species composition and abundance than the diversity of sponges.

The ultrastructure of carpospore differentiation for the red alga Cryptopleura ruprechtiana is described. Carposporogenesis proceeds through three developmental stages. After cleaving from multinucleate gonimoblast initials the terminal gonimoblast cells differentiate to produce carpospores. These young carpospores possess a large nucleus and numerous proplastids with a peripheral thylakoid. During the later stages of young carpospores starch begins to polymerize. Mucilage is formed within dilating concentric membrane bodies, thus forming mucilage sacs. The latter, subsequently, release their contents initiating carpospore wall formation. Intermediate-aged carpospores have more plastids which develop their internal thylakoid system. The endoplasmic reticulum produces granular cored vesicles. Mature carpospores have numerous fully developed plastids, large floridean starch granules and fibrous vacuoles. Curved dictyosomes produce cored vesicles and adhesive vesicles. The nuclear envelope is crenulated and a two-layered wall surrounds the mature carpospore.

In Mar del Plata the octocoral Tripalea clavaria is highly abundant on the different quartzitic rocky outcrops 18–20 m deep. Reproductive aspects of T. clavaria including its distribution and population structure have been described. Monthly sampling and observations were carried out by SCUBA diving from November 2000 to October 2001 at Banco del Medio (38°10′S 57°28′W). Tripalea clavaria occurs in patches; most colonies were 3·0–8·9 cm in height. The species appears to be a gonochoric brooder. Female colonies were significantly more abundant than males, which could be identified only from February to June, when spermaries were present. Oocytes were found even in very small colonies (from 3·5 cm height), being 40 to 200 μm in diameter, the predominant size-group around the year. Development of the oocytes required several months, beginning in May and ending with the production of larvae from March to May. Young, stalked oocytes were found at the base of the polyps attached to the mesenteries in May–June. During the following six months they grew in size; maximal oocyte diameter was 700 μm, observed in April/May. Asexual reproduction was negligible, indicating that population maintenance is based on sexual reproduction.

A new genus and species of sabellid polychaete from an organically enriched beach in São Sebastião, State of São Paulo, is described. Kirkia heterobranchiata is unique among sabellids for brooding the embryos on the dorsalmost pair of radioles, which exhibits several modifications for this purpose, rather than on ventral radioles. Morphologically, K. heterobranchiata is most closely related to Perkinsiana riwo, here referred to as the new genus, as suggested by phylogenetic analysis. The new genus is characterized by the shape of the lips (dorsal lips roughly triangular, broader than long; ventral lips lower, ventrally fused and distally rounded), by the absence of both radiolar and pinnular appendages, by having uncini with very short handles in both the thorax and abdomen, and by the ability to brood embryos in cocoons attached to the branchial crown.

Male Chondracanthus lophii was studied using light and electron microscopy. Observations on external morphology and internal anatomy are presented. Males possess a full set of functional mouth parts, the digestive system is active and the dominant cell type in the midgut is identified as the vacuolar type B-cell, but the gut is a blind ending sac with no anus. The gut contents were a homogenous, amorphous mass. The combination of active feeding and digestion with a blind ending gut supports the inference that males feed on special secretions produced by glands in the nuptial organs of the female. It is speculated that dependence on such secretion reduces or eliminates the production of faecal matter. Observations on the reproductive system confirmed the typical chondracanthid pattern.

Structural adaptations of the mouthparts and digestive tract of four talitrid amphipods were examined in relation to diet, habitat and phylogeny. The species differed in their habitat relative to the shoreline and also in their diet: a 5-dentate ‘sandrunner’, Talorchestia species II (a mid to low shore intertidal diatom feeder), a 5-dentate sandhopper, Talorchestia marmorata (a strandline kelp feeder); a 4-dentate sandhopper, Talorchestia species I (extreme high shore, feeding on spinifex grasses), and a 4-dentate landhopper, Keratroides vulgaris (forest leaf litter, litter feeding). Gross structural characteristics of the mouthparts were similar among all three Talorchestia species reflecting their phylogenetic relatedness. Increased setation and minor structural differences among the Talorchestia species could be attributed to dietary differences, reflecting the zones across the shoreline that they inhabit. Mouthparts of K. vulgaris were elongate, with markedly different setation to the Talorchestia species, reflecting its more distant phylogenetic position and its diet of decaying leaf litter. Digestive tract structure was more conserved among all species due to their phylogenetic relatedness. The gross digestive structure conformed to the general plan exhibited by most gammaridean amphipods. However, an additional pair of lateral pyloric caeca was evident in all species, the function of which is uncertain.

The swimming behaviour and photoresponses of the iridescent epipelagic copepods, Sapphirina gastrica and S. opalina were investigated in the laboratory. In continuous dark conditions, both species showed no significant diel variation in their swimming activities. When stimulated with light, they exhibited spiral-swimming in which the males showed a significantly higher speed and frequency of turning than the females. Both sexes of S. gastrica and S. opalina showed positive phototaxis at intensities higher than 0·05×1014 quanta  cm−2 s−1 for light sources of 430 nm and 580 nm. Sapphirina gastrica showed increased locomotion over a broad range of wavelengths from 430 nm to 580 nm, while S. opalina showed a gradual increase of activity with decreasing wavelength, with the highest value at 430 nm. The photoresponses of these two species suggest that light conditions play an important role in their daytime ascent and in determining the depth distributions that were observed in our previous study. It is suggested that the iridescence and fast spiral-swimming of males, and the species-specific photoresponses of both sexes constitute a putative mate recognition system in the open ocean.

The allometric growth of Uca leptodactyla from two distinct subtropical estuaries on the Brazilian coast was evaluated concerning its growth pattern and size at onset of sexual maturity. Females attained maturity at similar sizes in both sites (4·1 mm of carapace length in Indaiá and 4·2 mm in Ubatumirim), while males differed slightly. They reached the size at sexual maturity of 5·3 mm of carapace length in Indaiá and 4·6 mm in Ubatumirim. Growth pattern is usually similar among crabs from distinct sites while size at sexual maturity is frequently different. However, in the case of U. leptodactyla it did not occur, probably due to the strong habitat similarity and intrinsic features of this species.

Heterosaccus lunatus parasitizes the portunid crab, Charybdis callianassa, in Moreton Bay, Queensland, Australia. Larval broods, released during July and August (males only), were allowed to develop through to cyprids (lecithotrophic development). Speeds of all the developmental stages—nauplius I to nauplius IV and the cyprids were measured by timing continuously swimming larvae over 5 mm distances under a microscope. The absolute speeds of the naupliar stages were similar (3–4 mm s−1), but the cyprids were significantly faster at ≈10 mm s−1. These speeds were compared with published speeds of cirripede and copepod nauplii and other cirripede cyprids. Relative speeds (body lengths s−1) showed surprising parity, which for the cyprids probably reflects the similar efficiency of the fusiform shape and thoracopod propulsion for all sizes of this highly specialized larval form. The lecithotrophic H. lunatus nauplii have rather minimalistic appendages (compared with planktotrophic nauplii) which were examined at the light microscope and scanning electron microscope levels. The natatory setae were found to be plumo-denticulate.

Larvae of the hydrothermal vent barnacle Neoverruca sp. were reared under laboratory conditions and larval development was observed. Under these conditions, the larvae were released from adults as first-stage nauplii, although the larvae of other deep-sea barnacles have generally been considered to be released at a later larval stage such as the cyprid stage. The larvae of Neoverruca sp. were lecithotrophic through six naupliar stages and the subsequent cyprid stage. The larval period of Neoverruca sp. was more than 96 days under the present rearing conditions, which is the longest yet reported for barnacles. Most cyprid larvae, however, exhibited abnormal morphology and no larvae settled successfully on the substrate. These observations suggest that such a long larval period might enable neoverrucid barnacles to disperse between vent fields.

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.

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 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.

The pattern of planktonic abundance of juvenile Hydrobia ulvae was investigated in the Ria de Aveiro, Portugal, with the use of floating artificial collectors made of ‘hoghair’ filter, which were deployed for 2-day consecutive periods during 3·5 months. Abundance in the collectors followed a remarkably regular semilunar pattern, being higher during spring tides around full and new moons. Cross-correlation analysis between tidal range and captures in the collectors indicated a period of oscillation of the captures of 15 d, with maximum captures tending to occur on the day of the highest amplitude tides. The physical and behavioural mechanisms responsible for the pattern remain largely unknown. However, results from a simple model assuming that migration from the sediment to the water is dependent on current velocity suggest there is a minimum threshold in average current velocity integrated along the tidal cycle (and, therefore, in tidal amplitude) above which juvenile H. ulvae exhibit the floating behaviour. Artificial collectors may provide an effective and relatively easy and inexpensive technique for the study of dispersal of post-metamorphic molluscs.

The diet and functional biology of the digestive system of the cephalaspidean gastropod Haminoea orbygniana was investigated by gut content analysis of animals collected in the Ria Formosa, a coastal lagoon in southern Portugal. The results show that this species is herbivorous, stenophagic and probably non-selective, feeding mainly on diatoms (67·61%) and occasionally on vegetal detritus (4·16%) and Foraminifera (0·04%), but also including sand grains as an important part of the gut contents (28·34%). The role of the gizzard plates in the fragmentation of diatom frustules was demonstrated and is discussed. Data reveal that this process, although possibly important for the digestion and assimilation of food, seems not to be crucial. The role of sand as an additional food source and as an accessory tool complementary to the gizzard plates is discussed. A general review of the diet within the family Haminoeidae is presented, with all recent work indicating that they feed on diatoms and green algae.

DNA was extracted from mucus secreted by snails that had been allowed to crawl over glass microscope slides. The mucus contained many epithelial cells and a few blood cells. Microsatellite DNA regions were amplified using template DNA from the mucus and clear bands obtained showing the same positions as when using template DNA from the foot. Pedal mucus is therefore a reliable source of DNA, which can be extracted by a simple methodology that is readily applied in the field. The technique has considerable potential for conservation- and behavioural ecology.

Argopecten purpuratus was exposed to two different diets which reflected short term variations in quantity and quality of the natural food supply typical in bays of southern Chile. No significant differences of clearance rate were observed over different time periods at either of two food concentrations. The scallop reduced its clearance rate significantly when it was exposed to the higher food concentration. Pseudofaeces production occurred only at this high diet and the time factor had no significant effect on this process. The organic content of pseudofaeces was significantly lower than the organic content of the food, suggesting a pre-ingestive selection mechanism. Based on this capacity for particle selection, A. purpuratus was able to compensate for the differences in food quality of the experimental diets and ingesting particulate material containing 38% organic matter as a result of the selection process when fed at the higher food concentration. Absorption efficiency was lower following exposure to the high food concentration, suggesting that the experimental time of 72 h was not sufficient to acclimate the digestive response to a food supply significantly different from that of its habitat of origin. Phytoplankton form the principal nutritional source for this epibenthic species, and resuspended detritus, although occurring in large quantities, may only be of importance once digestive processes become acclimated to processing them.

A total of 39 Sepiola intermedia, Sepiola robusta and Sepiola steenstrupiana samples (11 female, 28 male), from the eastern Mediterranean and the Aegean Sea have been examined. The potential fecundity, relative fecundity and index of potential reproductive investment were calculated.

Males of the onychoteuthid squid Moroteuthis ingens implant spermatophores directly into a variety of internal and external tissues of the female, based on the examination of 14 individuals collected south of Tasmania, Australia. Furthermore, the capture of a pair of mating individuals suggests that ‘jaw locking’ reminiscent of cichlid fish may be a behaviour associated with courtship and mating.

The diet of the seven star flying squid, Martialia hyadesi, from the South Georgia sector of the Scotia Sea was described from stomach contents collected in winter (June) 2001. Diet was dominated by the hyperiid amphipod, Themisto gaudichaudii, fish (nine species, mainly myctophids) and cephalopods (mainly cannibalism). The absence of krill, Euphausia superba, and the presence of larger myctophids in the diet are discussed in terms of seasonal and annual prey availability.