This study analysed and compared the shell shape, morphometrics and relative growth of four sympatric limpet species (Patella depressa, Patella ulyssiponensis, Patella vulgata and Siphonaria pectinata) collected at Praia da Luz in Lagos (Algarve coast – southern Portugal). Morphometric relationships were established through regression analysis between linear (shell length, width and height), ponderal (total weight), area (shell base and surface areas) and volume variables (shell internal and total volumes). Relative growth (isometry vs allometry) was analysed to assess variation in the growth rate of morphometric variables throughout the species ontogeny. In addition, morphometric indices (ellipticity, conicity, density, surface area and volumetry) were calculated to further characterize shell shape. Overall, 1482 individuals with broad size and weight ranges were analysed (P. depressa = 354; P. ulyssiponensis = 306; P. vulgata = 408; S. pectinata = 414). All regressions were highly significant (P < 0.001) and the morphometric variables were strongly correlated (r = 0.761 to 0.994). Among 28 morphometric relationships, there were 14 isometries, 13 positive allometries and only one negative allometry. The morphometric indices revealed clear morphological differences between species and were mostly size-dependent, reflecting gradual changes in shell shape during growth. The main results are compared with a compilation of analogous data reported for these limpet species throughout their distributional range. Overall, the general trends in relative growth are discussed in terms of the species life habits, main traits and functional morphology.

The intertidal coastline of Ceredigion, Wales, comprises a patchwork of unstable sand and cobble beaches, and stable bedrock areas and boulder-fields. The last two shoreline types support rock-pools with growths of the red alga Corallina officinalis, the thalli of which are a popular substrate for calcareous epiphytes. Replicate samples of C. officinalis (four per site) were taken from (a) three bedrock sites (Ceinewydd, Aberystwyth Victoria Rocks and Castle Rocks) and (b) three boulder-fields (Llanon, Aberaeron lower shore (Aberaeron LS), Llanina) on the lower shore. The middle shore boulder field at Aberaeron (Aberaeron MS) was also sampled. These replicates were examined for calcareous meiofauna (63–2000 μm) not previously examined as a community: spirorbids, foraminifera, gastropods, bryozoans, ostracods and ophiuroids. These were assigned to sessile and vagile modes of life. The sessile association overwhelmingly dominated bedrock coastlines and the Aberaeron MS, while the vagile association was at its most abundant on the Corallina from lower shore, stable boulder-fields. Gastropods were almost entirely limited to Corallina on boulder-fields. We hypothesize that the boulders induce low-energy turbulence among breaking waves, allowing the less firmly attached vagile meiofauna to dominate on C. officinalis in rock-pools in lower shore boulder-fields. The small attachment area of sessile organisms allows them to settle bedrock sites in greater densities than do vagile organisms at boulder-field sites, which are presumed to require larger foraging areas.

Molluscan shells showing phenotypic variations are ideal models for studying evolution and plasticity. In north-eastern Asia, genetic and morphological diversity of the gastropod, Monodonta labio, were assumed to be influenced by both palaeoclimatic changes and current ecological factors. In this study, we examined spatial variations in shell shape of M. labio using general measurement and geometric morphometric analysis. We also investigated whether shell shape variation is best explained by environmental gradients or by genetic structuring, based on our prior molecular phylogeographic study. Two common morphological forms were observed among Chinese populations and in the adjacent Asian areas. Both the analyses revealed separation patterns in morphological variations of shell shape among the clades and populations. Environmental modelling analysis showed a significant correlation between shape variations and local maximum temperatures of the warmest month, indicating the role of natural selection in the evolution of this species. Data obtained in this study, combined with the cytochrome oxidase subunit I (COI) molecular phylogenetic data from the prior study, showed that morphological variations in M. labio were constrained by both local adaptation and phenotypic plasticity. We hypothesized that geographic separation by the Dongshan Landbridge was the first step towards its diversification, and that the temperature gradient between the East China Sea and South China Sea probably was the selective force driving the divergence of its morphological variations.

A taxonomic revision of the Nystiellidae from Brazil, including samples from the Rio Grande Rise, South Atlantic, was performed based on shell morphology. Five genera and 17 species were recognized. For the richest genus, Eccliseogyra, the three species previously recorded from Brazil were revised: E. brasiliensis and E. maracatu, previously known only from their respective type series, were re-examined. Newly available material of E. maracatu expanded the known geographic range of this species to off south-east Brazil. Eccliseogyra nitida is now recorded from north-eastern to south-eastern Brazil, as well as from the Rio Grande Rise. Three species of Eccliseogyra are newly recorded from the South Atlantic: E. monnioti, previously known from the north-eastern Atlantic, occurs off eastern Brazil and on the Rio Grande Rise; its protoconch is described for the first time, confirming its family allocation. Eccliseogyra pyrrhias occurs off eastern Brazil and on the Rio Grande Rise, and E. folini off eastern Brazil. The genus Iphitus is newly recorded from the South Atlantic. Iphitus robertsi was found off northern Brazil, although the shells show some differences from the type material, with less-pronounced spiral keels. Additional new finds showed that Iphitus cancellatus ranges from eastern Brazil to the Rio Grande Rise, and Iphitus notios sp. nov. is restricted to the Rio Grande Rise. Narrimania, previously recorded from Brazil based on dubious records, is confirmed, including the only two living species described for the genus: N. azelotes, previously only known from the type locality in Florida, and N. concinna, previously known from the Mediterranean. A third species, Narrimania raquelae sp. nov. is described from eastern Brazil, diagnosed by its numerous and thinner cancellate sculpture. To the three species of Opaliopsis previously known from Brazil, a fourth species, O. arnaldoi sp. nov., is added from eastern Brazil, and diagnosed by its very thin spiral sculpture, absence of a varix, and thinner microscopic parallel axial striae. Papuliscala nordestina, originally described from north-east Brazil, is recorded off eastern Brazil and synonymized with P. elongata, a species previously known only from the North Atlantic.

The present study reports morphometric relationships and discusses the relative growth in the banded murex (Hexaplex trunculus) and the purple dye murex (Bolinus brandaris) from the Ria Formosa lagoon (southern Portugal). A total of 11 morphometric parameters (eight linear variables: shell length, shell width, total aperture length, aperture length, aperture width, spire length, spire width and siphonal canal length; three ponderal variables: total weight, soft parts weight and shell weight) were analysed in both species. The analyses comprised numerous individuals of both sexes and with broad size ranges (H. trunculus: 10.7–82.8 mm shell length; B. brandaris: 14.6–107.7 mm shell length), fairly representative of the populations from the Ria Formosa lagoon. In general, B. brandaris exhibited greater morphological plasticity and higher variability in shell shape compared with H. trunculus. In both species, the vast majority of morphometric relationships displayed positive allometries, distantly followed by negative allometries and by isometries. Although H. trunculus and B. brandaris are known to lack external sexual dimorphism, several morphometric relationships revealed significant differences in the type of growth between sexes, which should be further confirmed using more powerful techniques, such as geometric morphometric analyses of shell shape.

A gastropod fauna has been studied from upper Pliensbachian – upper Toarcian deposits of two sections of the Causses Basin (southern France) in order to investigate the mode of recovery after the early Toarcian anoxic event. The fauna consists of 15 species, one of which is new (Bathrotomaria kronzwilmesorum sp. nov.). Their stratigraphical distribution shows two peaks of diversity – in the Bifrons Zone (Bifrons Subzone) and in the Aalensis Zone (Mactra Subzone) – which reflect brief times during which the oxygen content and bottom consistency favoured the settlement of a relatively diversified fauna. In the Variabilis–Pseudoradiosa zones, gastropods are only represented by two species. This probably indicates more severe and unstable environmental conditions, only allowing the survival of gastropod taxa with wide adaptive capacities. The very low species diversity and the discontinuous and slow faunal recovery were probably determined by physiographic factors. The Causses area was a small basin confined by exposed lands and open towards the central part of western Tethys. Gastropods described here occur exclusively in the Toarcian – early Aalenian communities of the European epicontinental seas, whereas species from the central region of western Tethys are absent. Geographic isolation and marginal location of the Causses Basin restricted faunal exchange with the western European epicontinental seas, preventing fast recovery after the anoxic event. Gastropods of the central region of the western Tethys were probably unable to settle and colonize that area due to the strongly different environment.

The marine gastropod Anachis aliceae (Pallary, 1900) is reported with certainty for the first time from the Algarve, south coast of Portugal from species-rich rocky priority biotope. Several live specimens of this species belonging to the Columbellidae family were collected and identified from by-catch samples, recovered from octopus traps set at depths between 50 and 70 m off Ponta da Piedade. Taxonomic validation of the newly recorded species is based on the comparison to other related species within the genus.

Crabs are thought to play a vital role in structuring gastropod populations. Studies quantifying the frequencies with which crabs attack gastropods in natural settings are, however, scarce. Although a wide variety of techniques exist with which predator–prey interactions can be investigated (e.g. laboratory experiments, exclusion caging, tethering and population surveys), there is a need for methods that can provide large amounts of quantitative data, particularly documenting the frequency with which crabs attack gastropods. This study examines the utility of using wax replicas of gastropods to determine crab attack frequencies. Replicas of Chlorostoma funebralis, Nucella ostrina and Nucella lamellosa were bolted to mesh screens and deployed in the rocky intertidal. Crabs attacked wax replicas of gastropods, leaving characteristic marks in the wax. In most cases, the appendage used in the attack could be identified from the marks (i.e. chelae vs walking legs). The effectiveness of this technique was verified using surveys of repair scar frequencies of the gastropod populations; patterns in attack frequency, determined from the number of marked wax replicas, were consistent with those of repair frequency, in that both were greater at the wave protected, quiet water locality. This study confirms the value of wax replicas in investigations of crab predation to determine the frequency and type of attack, and illustrates the potential of this method for quantifying predation intensity. The development of techniques that quantify the magnitude and exact nature of the effects of crab predation on intertidal communities is pivotal, given the intensity of commercial fishing of some species of crabs.

Some shells of Ophieulima minima are reported from the Tuscan archipelago. This is the first record of the genus Ophieulima from the Mediterranean Sea. Hypotheses about its host are considered.

Three specimens of the genus Corambe were found in the intertidal zone of Santos, São Paulo (Brazil); two of them were identified as C. evelinae and one as C. carambola. Both species are reported for the first time since more than about 40 years ago.

Molluscs from the Insect Limestone of the Bembridge Marls Member are described. The gastropods Lymnaea (Galba) longiscata (Brongniart 1810), Planorbarius discus (Edwards 1852), Gyraulus similis Férussac, 1814, Hippeutis headonensis Jodot, 1942, Viviparus lentus (Solander 1766) and Viviparus angulosus (J. Sowerby 1817) indicate freshwater alkaline conditions. The cerithioid gastropod Tarebia acuta (J. Sowerby 1822) probably represent more brackish conditions. Polymesoda (Pseudocyrena) obovata (J. Sowerby 1817) is the only bivalve present. All were potentially washed into the depocentre. Despite a wide outcrop of the Insect Limestone on the Isle of Wight's northwest and northeast coasts, there are no records of molluscs other than from the Gurnard/Thorness Bay area on the northwest coast of the island.

Buccinidae—like other canivorous and predatory molluscs—are generally considered to be occasional visitors or rare colonizers in deep-sea biogenic habitats. However, casual observations during tropical deep-sea cruises suggest that associations between buccinids and sunken wood, in particular, are not fortuitous. Enigmatocolus monnieri has been found to co-occur in Madagascar with bathymodiolines, vesicomyids and solemyids, indicating the presence of seeps, and species of Thermosipho gen. nov. have been sampled by submersibles and remotely operated vehicles, exclusively from hydrothermal vents. A molecular phylogeny (based on CO1, 12S and 28S genes) reveals that buccinid genera potentially associated with sunken wood (Eosipho, Gaillea gen. nov., Calagrassor gen. nov., and Manaria) are closely related to taxa from vents (Thermosipho gen. nov.) and seeps (Enigmaticolus). The anatomy of several dissected species did not reveal any special trait that could be interpreted as a special adaptation to biogenic substrates. Buccinids from sunken wood are most diverse in the Indo-Pacific centre of marine biodiversity, the ‘Coral Triangle’, at depths between 100 and 1000 m, with numerous species still undescribed.

The ultrastructure of spermatogenesis, the euspermatozoa and paraspermatozoa, is investigated in Trophon geversianus. Spermatogenesis follows the general developmental pattern of caenogastropods. Paraspermatid development is characterized by elongation of the cell, concurrent with the appearance of a cytoplasmic elongation at the apex of the cell and the breakdown of the nucleus into small round fragments (caryomerites). Euspermatozoa consist of: a tall, conical acrosomal vesicle (with a invagination); a rod-shaped, highly electron-dense nucleus with an internal axoneme; an elongate midpiece consisting of the axoneme sheathed by helical mitochondrial elements; an elongate glycogen piece; and a short free-tail region. Paraspermatozoa of T. geversianus are vermiform. They contain approximately 12–16 axonemes arranged peripherally, numerous oblong dense vesicles, numerous less dense (round) vesicles, and scattered mitochondria. Most of the euspermatozoal features of T. geversianus are also observed in many neogastropods. However, the presence of the axoneme continuously located inside of the nucleus has not been reported before, and may prove to be a diagnostic feature of the Muricidae.

The nudibranch Thordisa villosa is recorded for the first time from the west coast of India. It is the third known record of this species from India, observed after a long gap of 60 years. The last known record of this species from India was by Satyamurti (1952), from the Gulf of Mannar on the south-east coast. Specimens were collected in the intertidal rocky shores of Maharashtra and Gujarat. The occurrence of the species at three study sites confirms its range in this part of the Indian coastline.

This study was conceived to evaluate seasonal changes in the lipid reserves of the digestive gland of the carnivorous intertidal caenogastropod Nucella lapillus, using a stereological approach. Volume density of lipid droplets in the digestive gland, digestive gland weight and volume were assessed in animals collected in March, June, September and December on the Portuguese coast. Gonad development was evaluated to detect any relationship between lipid content in the digestive gland and the reproductive cycle. The quantitative light microscopic analysis demonstrates that lipid droplets are a major component of the digestive gland. In males, the digestive gland and its lipid reserves were quite stable without significant variations throughout the year. In females, the percentage of digestive gland volume occupied by lipid droplets was higher in June and December, coinciding with the highest values of digestive gland volume. Due to the conjugation of these two factors, in June and December the total amount of lipids in the digestive gland was substantially increased in females. In both males and females a relationship between the development status of the gonad and the lipid reserves of the digestive gland was not evident. However, significant differences in the digestive gland lipid reserves were detected between males and females in June and December, pointing to a sex related effect on lipid reserves. To evaluate the use of lipid reserves as energy source in N. lapillus, the consumption of digestive gland lipids was followed during a starvation experiment.

Molluscs from the Middle and Upper Ordovician succession of Girvan, SW Scotland are common and diverse in some localities. The mollusc fauna consists mainly of gastropods, bivalves and various univalved molluscs (mimospirids and tergomyans), along with scarcer polyplacophorans, rostroconchs and cephalopods. The present study gives an overview of the distribution and palaeoecology of bivalves, gastropods and univalved molluscs and compares them with mollusc faunas worldwide. Gastropods, mimospirids and tergomyans are present from the Darriwilian (mid Llanvirn) onwards in both siliciclastic and carbonate facies, and increase in diversity through the Sandbian (Caradoc) and into the Katian (Ashgill). Bivalves first appeared in Girvan in the late Darriwilian (early Caradoc) in deep water siliciclastic facies; where they continued to be more abundant and diverse than in equivalent carbonate facies. Molluscs are initially Laurentian in aspect, though peri-Gondwanan faunal elements occur, particularly during the Sandbian. The pattern of bivalve and gastropod diversity found in the Ordovician of Girvan generally follows that of the known global diversity for these groups.

Iheyaspira bathycodon sp. nov. is described from the Von Damm Vent Field on the world's deepest spreading centre, the Mid-Cayman Spreading Centre (MCSC), Caribbean, at 2300 m depth. The new species is defined and illustrated from 11 specimens, with brief notes on habitat and known distribution. Molecular phylogenetic data from partial COI mDNA, 16S rDNA and nuclear 18S rDNA regions are used to analyse the species’ phylogenetic position and its morphology is compared with previously described skeneid and vent taxa. The new species is distinguished from the most closely allied vent species, Iheyaspira lequios Okutani, Sasaki & Tsuchida, 2000 by morphological differences in radula diagnosis and appendage structure of the head-foot. Iheyaspira bathycodon sp. nov. is the tenth turbinid to be described from a hydrothermal-vent environment and the second species to be named from recently discovered hydrothermal vents on the MCSC. Determining the faunal composition of assemblages at the vent fields of the MCSC will help to elucidate the vent biogeography of the region.

Qeshm Island is the largest island of the Persian Gulf. It is located in the north-eastern part, near the Strait of Hormuz, which connects the Persian Gulf with the Gulf of Oman. Between 2007 and 2010 by support of the Persian Gulf Biotechnology Research Center a collection of the two most dominant macrobenthic fauna groups (Gastropoda and Crustacea) was gathered around the island. A total of 28 intertidal stations were investigated, including four basic habitat types (rocky, sandy, mud flats and mangrove forests), which resulted in a large diversity of species encountered. The present report provides a summary of the collected taxa. A total of 123 taxa belonging to Crustacea and Gastropoda are recorded in the present study. Identification of the species up to the lowest possible level was attempted; about 88% were identified up to species level. In total, 109 species have been identified. Rocky sites were the most diverse intertidal habitats in the island.

The carnivorous gastropod Xandarovula patula is a species being known to mainly occur west and south-west of the UK, down to the Atlantic coast of Spain. It also was recently reported from the central parts and the periphery of the North Sea, up to Trondheim (Norway). Now, it was also recorded during a survey of the epibenthic faunal composition from the Dogger Bank in winter 2011. The collecting stations are located on a routine station on the western Dogger Bank at a depth average of 25 m, as well as off the south-western edge of the Dogger Bank at a mean depth of 65 m. The bottom of both stations is covered with sparse boulders and rubble with a dense cover of Alcyonium digitatum, the preferred food of Xandarovula patula. This is another example for the spreading of oceanic ‘warm water’ species towards the central North Sea along the main, northern currents. The present work summarizes all records of X. patula from the North Sea available in the literature up-to-date and verifies rising water temperatures at the main area of recent records at the Dogger Bank, possibly promoting the species' spreading.