Seven syntypes of Halichondria isodictyalis, type species of Lissodendoryx, were rediscovered and studied. By choosing a lectotype and studying it along with the paralectotypes, we find that L. isodictyalis, subgenus Lissodendoryx, is a Caribbean sponge characterized by smooth megascleres, ectosomal tylotes and choanosomal styles, and one size-class of microscleres comprising arcuate isochelae and sigmas. Having determined these characteristics, we re-erect Lissodendoryx (Lissodendoryx) carolinensis (previously synonymized with L. isodictyalis), with the same smooth megascleres but two distinct size categories of microscleres, isochelae and sigmas; and we add a new western Atlantic species, Lissodendoryx (L.) spinosa sp. nov., with coarse spines on the megasclere terminals and with two size-classes of isochelae and sigmas. Other species in the region are Lissodendoryx (L.) colombiensis, with smooth tylotes and robust strongyles, and two categories of microscleres (isochelae and sigmas) accompanied by conspicuous raphids arranged in trichodragmas; Lissodendoryx (L.) strongylata, with smooth tylotes and slim strongyles, one size-class each of isochelae and sigmas, rare and very thin raphids. Lissodendoryx sigmata is here assigned to the subgenus Anomodoryx, with smooth tylotes exclusively as megascleres, two size-classes of isochelae, and one or two sizes of sigmas; it may represent a species complex far more diverse than previously thought. To this subgenus we add another species, Lissodendoryx (A.) amphispinulata sp. nov., characterized by fine spines ornamenting both tyles of part of the tylotes. A third subgenus, Ectyodoryx, is represented by Lissodendoryx (E.) acanthostylota sp. nov., with smooth tylotes and finely spined acanthostyles in two size-classes, as well as two size-classes each of isochelae and sigmas as microscleres. All species studied alive occur in shallow lagoon habitats with mangroves and sea grass (Thalassia) but museum specimen records show that some may reach a depth of 60 m.

This paper presents baseline information on maternal behaviour and lactation in the Mediterranean monk seal, with particular focus on the age at which pups are weaned. The study was conducted in the western Saharan population, the only surviving colony of the species. The first moult finished at a mean pup age of 72.3±17 d (N=17) and, in contrast to other taxonomically-related phocids, this process was not associated with weaning. Lactation lasted a mean of 119.4 d (N=9; range: 103–149 d) in the pups that could be monitored until full weaning had taken place. This period almost doubles the maximum lactation length reported in other phocid species. During the first week after birth the mother–pup bond was well developed and mothers always remained with their pups. The time invested in nursing (17%, SD: ±36) and in mother–pup interactions (14%, SD: ±32) was higher during this period than afterwards (8%, SD: ±23 and 4%, SD: ±19, respectively). After the first week, nursing continued but mothers started to leave their pups in order to feed at sea. Weaning occurred gradually. Already since birth, pups were active and mobile, and swam frequently before moulting or weaning occurred. Fostering and milk stealing were common patterns of behaviour for both lactating females and pups. In 26.6% of the suckling episodes observed in mother–pup pairs of known identity, pups suckled from females other than their mothers. Some females nursed more than one pup, at least occasionally, and in some cases a pup was fostered long-term by an alien female. The Mediterranean monk seal exhibits maternal-care characteristics that are more like otarids than phocids. This observation contradicts previous proposals that a short lactation period is a phylogenetic characteristic of phocids. Several of the unusual maternal traits observed may be favoured by year-round access to abundant food supply, availability of breeding sites, and mild climatic conditions. This information should be taken into account when designing conservation strategies for the species and, very particularly, in the implementation of pup rehabilitation programmes.

The predatory caenogastropod Hexaplex trunculus employed different methods to access different species of bivalve prey characterized by different shell thicknesses. Hexaplex trunculus drilled Callista chione and Venus verrucosa at their shell margins but the latter species also laterally. It also attempted to drill two species of Tapes but successfully penetrated these only after chipping the shell margin. Chipping, whereby a labral spine is forcibly pushed between the prey's valves, especially posteriorly, to break them followed by proboscis insertion, was typically applied to access the thinner shelled prey Cerastoderma glaucum whereas Modiolus barbatus and Mytilus galloprovincialis were either chipped or drilled. The pattern of M. galloprovincialis shell penetration appears related to predator and prey size. Small (40 mm shell height) H. trunculus tended to drill rather than marginally chip M. galloprovincialis. Medium sized (55 mm shell height) H. trunculus either chipped or drilled M. galloprovincialis in approximately equal proportions but also at the valve margin. Larger (70 mm shell height) H. trunculus tended to laterally drill average sized (35 mm shell length) and the biggest (65 mm shell length) M. galloprovincialis. When larger M. galloprovincialis are attacked it thus becomes increasingly more difficult for H. trunculus to chip and drill the shell margin, possibly because the periostracum is thicker here in such individuals, and the predator resorts to lateral drilling. This is possible because as the mytilid ages its surface periostracum becomes progressively eroded and thus thinner and easier to access. Scanning electron microscopy (SEM) identified shell microstructure damage which shows that the chipping and drilling behaviours of H. trunculus result from labral spine damage and dissolutional etching, respectively, rather than mechanical radula rasping. These observations have implications for the use of such predation marks to identify the predator taxon implicated from holes in either empty Recent shells or fossil material.

Egg development time and hatching success were determined for the oncaeid copepod, Triconia canadensis, from the mesopelagic zone of the western subarctic Pacific. The egg development time was estimated to be 74.7–84.5 days at in situ temperature (3°C), which is much longer than those reported previously on the other oncaeid copepods even if the differences in experimental temperatures are taken into account. The egg hatching success varied between 50 and 100%, with a grand mean of 88%. The newly hatched nauplii of T. canadensis were elongate ellipsoid in shape, and had many large-sized lipid droplets in their body. Possible adaptive significance of apparent longer egg developmment time of T. canadensis is discussed in the light of their life cycle strategy.

Several types of relationships link organisms to each other, including competition, predation and various types of associations. This paper presents the first case of association/interaction between dugongs, Dugong dugon, the only strictly marine herbivorous mammal, and three species of tropical dolphins in and around the lagoon of Mayotte (45°10'E 12°50'S), in the western tropical Indian ocean. Data were collected opportunistically from 1999 to 2005 in the surrounding waters of Mayotte from boat (N=2 observations) and ULM (ultra-light motorized vessel, N=2). The dolphin species involved in associations with dugongs were Indo-Pacific bottlenose dolphin, Tursips aduncus, Indo-Pacific humpback dolphin, Sousa chinensis, and spinner dolphin, Stenella longirostris. In one case, dugongs were associated with both bottlenose and humpback dolphins. Associations were observed in the protected waters of the lagoon and outside, along the external slope of the barrier reef. Group size, activity and group structure of each species were recorded. Behavioural observations suggest that dugongs and dolphins were engaged in similar activities, such as travelling, on several occasions and were clearly associated when group formation was tight. If dolphins and dugongs may not associate for feeding purposes, then these interactions may occur: (1) for predation avoidance toward sharks; or (2) without any ecological reasons due to dolphin and dugong habitat overlap around the island.

The ultrastructure of sperm of an acochlidian opisthobranch is described for the first time in detail, in the tiny, gonochoristic Microhedyle remanei (Microhedylidae) from Bermuda. Transmission electron microscopy (TEM) shows the spermatozoa of M. remanei sharing many plesiomorphic features with opisthobranch gastropods, such as having an apical spiral nucleus with a basal invagination filled with a bell-shaped centriolar derivative; there is a single glycogen helix embedded into matrix and paracrystalline material. Sperm of M. remanei are characterized by possessing a strongly helically coiled nucleus with up to five keels terminating into one very prominent and intertwined keel. The sperm midpiece shows the glycogen helix which is very densely arranged. This clearly differs from Hedylopsis ballantinei, a member of the related acochlidian family Hedylopsidae, where three glycogen helices with different lengths and a probably much shorter nucleus are present. This variation among acochlidian sperm may be phylogenetically relevant and may be related to special acochlidian reproductive features such as sperm transfer via hypodermic injection or dermal fertilization via spermatophores.

Intertidal individuals of Mytilus galloprovincialis were exposed to anaerobiosis in laboratory at 22°C and a set of biochemical metabolites and survival potential determined. Differences in survival potential between individuals emersed or kept in oxygen-free seawater were residual according to ST50 values (survival time, P[asymp ]0.05) but emersed individuals survived significantly longer when considering ST90–100 values (P<0.05). Anaerobiosis was similarly activated under both emersion and incubation in anoxic seawater after 6 h according to a seven-fold increase in succinate. Longer exposure of individuals (up to 48 h) caused succinate (and propionate) to increase but in a higher magnitude under incubation with anoxic seawater. Propionate appeared in soft tissues after 24 h of incubation in anoxic seawater and after 48 h when individuals were emersed. Glycogen was not utilized after 6 h in any case, but was progressively used with longer exposure times and in a higher magnitude under incubation in anoxic seawater (48 h). Adenylate energy charge (AEC) was highly affected by both exposure time (P<0.001) and anaerobic treatment (P<0.01). Rapid breakdown of ATP and phospho-L-arginine (PLA) did occur during the first 24 h of anaerobiosis, the latter ATP drop was accompanied by slight increase of ADP but strong increase of AMP that accumulated in a higher magnitude under incubation in anoxic seawater. Biochemical results of the present study suggested a certain degree of aerobiosis for emersed M. galloprovincialis that in turn is linked to a slight but significant longer survival performance. Most significant biochemical changes occurred during the first 24 h of oxygen deprivation, but significant differences between treatments were observed after 24–48 h. These lag differences in biochemical metabolites together with more accurate survival analyses have to be considered when investigating the energy metabolism linked to the anaerobic performance of M. galloprovincialis.

Four new species of cheilostome Bryozoa from the hippothoid genus Antarctothoa (formerly subgenus Antarctothoa, Moyano 1987) are described. Antarctothoa bougainvillei (d'Orbigny) and Antarctothoa dictyota (Hayward) are re-described from material collected from Patagonia and South Georgia respectively.

An increasing number of cryptic species are being discovered within sponges with assumed wide geographical distribution. Pachymatisma johnstonia (Bowerbank in Johnston, 1842) (Astrophorida: Geodiidae) is one of the most common and known sponges throughout the north-east Atlantic coasts. Pachymatisma normani Sollas, 1888 is a northern species previously synonymized with P. johnstonia by Topsent. It is here redescribed on the basis of fresh material from the type locality, the Korsfjord in the Bergen area (Norway). Spicules are shown to be reliable characters to distinguish the species investigated. Pachymatisma normani is characterized by larger spicules, most markedly in the sterrasters. Our observations also suggest that habitat and gross morphology distinguish P. johnstonia from P. normani. Furthermore, using a partial sequence of the cytochrome c oxidase subunit I (COI) and an ITS1-5.8-ITS2 nuclear fragment, we show that consistent genetic differences exist between the two species. A brief overview of the genus and a key to the known species are also given.

Wedding shrimps, Spongicoloides koehleri, spend the adult phase of their life cycle within the cavity of a hexactinellid sponge. Although there is little light at the depths at which the sponges are found, the shrimps do not use the highly sensitive reflecting superposition optics commonly found in other shrimp-like decapods. Instead they have apposition eyes which are virtually free of shielding pigment. It is proposed that this is due to the paedomorphic retention of the larval optics through the process of neoteny.

A systematic survey of the sponge fauna of the Aegean Sea has been carried out. Twenty-eight stations located in the Aegean Sea were explored and 59 species of Demospongiae were collected from this particular area, which covers a broader geographical area of the Aegean and Cretan Seas. Some of the species found are poorly known for the Mediterranean fauna, like Cerbaris curvispiculifera and Spongosorites flavens, which are reported for the first time in the Aegean Sea and generally in the eastern Mediterranean. The species Axinyssa michaelis sp. nov. (Halichondriidae: Halichondrida) is new to science. In this paper, a description of the new species is presented along with the description of the first recorded species in the Aegean Sea. In addition to the taxonomic description of the species, some ecological data and a distribution pattern are also presented.

Many warm-water (Lusitanian) species reach their limits in the central English Channel, failing to penetrate to the North Sea. We re-surveyed the eastern limits of the Lusitanian intertidal barnacles Chthamalus montagui and C. stellatus, from 1994 to 2004, a decade of exceptionally high sea temperatures, and found range extensions on both sides of the Channel compared to the 1950s and 1970s. Annual recruitment of Chthamalus on the English coast was monitored. There was a consistent gradient of low recruitment to the east of Portland Bill, with significant reductions coinciding with prominent headlands. Highest recruitment occurred during the warmest years. Cluster analysis showed a high degree of similarity of annual recruitment within coastal cells suggesting that local processes are also important. In 1999 we compared recruitment in the other common intertidal barnacles, the boreal Semibalanus balanoides and the non-native Elminius modestus, with Chthamalus spp. All species showed low recruitment between Selsey Bill and Portland Bill, suggesting habitat limitations and/or hydrographic mechanisms. Annual recruitment of Chthamalus at existing limits on the Isle of Wight was positively correlated with the number of days of westerly and south-westerly winds during the summer, coinciding with the pelagic larval phase. A ‘pulse’ of high Chthamalus recruitment on the Isle of Wight, measured during the summer of 2000, reversed population decline. Only a higher frequency of such pulses will maintain populations at existing limits and increase the rate of range extension towards the North Sea. Such extension will be limited by lack of hard substrata, but proliferation of coastal defence schemes in recent years is increasing suitable habitat for barnacles.

Between 1993 and 2005, 68 sightings of southern right whales were recorded along 400 km of coastline between Paraty Bay (23°13'S 44°42'W) and Macaé (22°22'S 41°47'W), Rio de Janeiro State, south-eastern Brazilian coast. Mother/calf pairs represented 66.1% of sightings. Only solitary individuals showed a distinct pattern of occurrence. Females with calf did not show a distinct pattern of occurrence suggesting their widespread distribution in the area. Analysis of the records and detailed accounts of the sightings of southern right whales reveal that there exist conflicts between the animals and human activities such as harassment and collision with boats during attempted rescues, accidental entanglement in fishing nets and intentional mortality, which may have a bearing in the conservation of the species in Brazilian waters.

The increasing occurrence of imposex in marine gastropods has been related to their exposure to the tri-substituted organotin compounds tributyltin (TBT) and triphenyltin (TPhT), which have been widely used as antifouling agents, and has been documented for more than 200 gastropod species. Odontocymbiola magellanica, a large benthic neogastropod, showed 85–100% imposex near harbours with high marine traffic in Patagonia. We evaluated if, as predicted by the energy allocation hypothesis, females with imposex (FWI) were on average larger and/or heavier than normal individuals, and if there were differences in shell morphometry associated with imposex, using both univariate and multivariate approaches. We detected differences in two morphometric variables, but no overall effect in shell shape, and ~10% of reduction in body weight in FWI. In addition, the multivariate index of size suggested a positive effect on FWI, in contrast to univariate analyses showing no differences in shell length. The present results demonstrate that responses to TBT vary among gastropod species and that the energy allocation hypothesis may be useful only under certain conditions.

The mating pattern of Littoraria flava, a typical grazer snail of the supralittoral zone and sometimes the midlittoral zone of boulder shores in tropical and sub-tropical regions, was examined to determine the occurrence of size-assortative mating and sexual selection on size. We also evaluated its reproductive behavioural mechanisms, as well as their implications for the evolution of the species. The population was investigated from May 2001 through April 2002, on an artificial rocky shore composed of a boulder wall at Flexeira Beach, Itacuruçá Island, Rio de Janeiro, Brazil (22°56′S 43°53′W). The current study showed that: (1) copulating pairs were observed only from November through March, indicating seasonal reproduction of the population; (2) linear correlation between sizes of copulating mates were weak but significant, characterizing assortative mating by size; (3) there was sexual selection for female size, i.e. large females were favoured as mating partners over small ones; however, sexual selection on size was not observed among males; (4) there were significant positive correlations between male and female shell sizes and the copulation time; (5) there were significant differences in copulation time among different types of copulating pairs; and (6) mating females were significantly larger than non-mating females, while there were no differences between the sizes of mating and non-mating males, indicating differential sexual selection between sexes. These findings may contribute to the evolution of sexual dimorphism in this species. Male choice behaviour plausibly explains the assortative mating and sexual selection on female size of Littoraria flava. As males chose larger mates because they benefit reproductively therefore large females have increased chances of mating and fertilization (sexual selection for size). Further evidence suggests that large females are more successful than small females in carrying out mating, because large females remain in copulation for a longer time than do small females.

The ecology and biogeography of meiofauna at deep-sea hydrothermal vents have historically received less attention than those of mega- and macrofauna. This study examines the composition of major meiofaunal taxa in beds of the mussel Bathymodiolus thermophilus at hydrothermal vents on the northern and southern East Pacific Rise (EPR) and presents the first comparison of species assemblages of the dominant taxon, the nematodes, among sites spanning 27 degrees of latitude. Meiofaunal samples were collected by submersible from three mussel beds at 9°N on the EPR and four mussel beds between 17 and 18°S in 1999. Estimated ages of the mussel beds at the time of sampling range from 4 to >20 years, enabling investigation of the influence of mussel bed age on meiofaunal assemblages. Overall, the meiofauna of the mussel beds was dominated by nematodes, with copepods constituting the second most abundant meiofaunal group. There was variation in the ratio of nematodes to copepods between sites, however, with copepods more abundant than nematodes in the youngest mussel beds. Apart from polychaete larvae, other meiofaunal groups were generally present at very low abundance (<1%) in the samples and restricted in diversity to gastropod larvae, acari, foraminifera, ostracoda and turbellaria. Seventeen nematode species from 14 genera and 11 families were found in the samples, with no evidence of endemicity to hydrothermal vents at the generic level. Four genera present were not previously recorded at hydrothermal vents. Nematode species richness, species:genus ratios and abundances were low compared with other deep-sea habitats, though the ecological relevance of comparisons with soft-sediment benthos is discussed. Nematode assemblages exhibited high dominance by a few species, with one species of Thalassomonhystera most abundant at five of the seven vent sites. Multivariate analysis of nematode assemblages reveals similarities among sites that do not match geographical proximity. The youngest mussel beds were most similar to each other and exhibited lower species richness than other sites, consistent with colonization of mussel bed habitat by nematodes over time. Similarity in the composition of nematode assemblages among sites separated by ~3000 km indicates that they lie within a single biogeographic province, consistent with that proposed for mussel bed macrofauna. At a generic level, samples exhibited some overlap with nematode assemblages at vents elsewhere on the EPR, on the Mid Atlantic Ridge and in the North Fiji Basin.

Five new species of sponges are described from the coast of Lebanon in the eastern Mediterranean, Levantine Basin. Euryspongia raouchensis (Dysideidae), Liosina blastifera (Dictyonellidae) and Niphates toxifera (Niphatidae) belong to genera that are new for the Mediterranean but widely distributed in the tropics. Cinachyrella levantinensis (Tetillidae) and Ciocalypta carballoi (Halichondriidae) are described in genera with a restricted distribution in the Mediterranean, which have affinities with species from the Atlantic West African coast. These species do not appear to be lessepsian migrants, but are interpreted as remnants of an ancient thermophilous fauna that survived in the easternmost part of the Mediterranean.

Egg capsules and intracapsular embryos of Rapana venosa were studied to determine the reproductive pattern of this invader species in the south-eastern Black Sea. Egg deposition of R. venosa in the laboratory at 25°C was described. Egg laying began in mid-June, reached a peak in July and ended in late August in 1996. The total number of the egg capsules per whelk ranged between 197 and 999 (mean 575 ±41). The mean length of the egg capsules was 13.26 mm. Each capsule contained between 124 and 1090 embryos with a mean of 555 ±10. Mean larval production per rapa whelk was about 392,931 ±42,731. The mean size of eggs produced was 213.8 μm. Five different stages of intracapsular development were observed. Embryos developed without nurse eggs. Veliger larvae completed their intracapsular development and hatched in 22 days at 25°C.

Hawaiian spinner dolphins (Stenella longirostris) feed offshore at night on mesopelagic prey and move to protected shallow waters in early morning to rest. We hypothesized that this behaviour would make them particularly sensitive to anthropogenic factors in these rest areas and would affect their overall behaviour and their population frequency. To test our hypothesis we collected data in a known rest area along the north-west coast of the island of Oahu during August of 2001, 2002 and 2003. Using land- and water-based surveys, we evaluated dolphin group size, counted boats, kayaks and swimmers in the vicinity of the dolphins (<40 m) and reported any changes in dolphin behaviour. Our results demonstrated a stable dolphin habitat frequency over the three summers, which emphasizes the critical value of this rest area for this spinner dolphin population. The results also showed an increase in dolphin-oriented activities, but we could not draw any definitive conclusion on their real impacts on spinner dolphin ecology and ethology.

This article is a review of the genus Richtersia (Nematoda: Selachinematidae) with a key to species, genus diagnosis and lists of valid species. Two new Richtersia species from the Golfo San José and Golfo San Matías, Chubut province of Argentina are described: Richtersia bicornis sp. nov. is characterized by having two thorn structures after cuticular collar, and in total 32–40 longitudinal rows of spines arranged in eight groups in cervical region and precloacal spines similar in shape. Richtersia argentinae sp. nov. is characterized by the number of longitudinal rows of spines, amphid size and the precloacal spines configuration.