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Marine molluscs are of enormous scientific interest due to their astonishing diversity in terms of their size, shape, habitat, behaviour, and ecological roles. The phylum Mollusca is the second most common animal phylum, with 100,000 to 200,000 species, and marine molluscs are among the most notable class of marine organisms. This work aimed to show the importance of marine molluscs as a potential source of nutraceuticals as well as natural medicinal drugs. In this review, the main classes of marine molluscs, their chemical ecology, and the different techniques used for the extraction of bioactive compounds have been presented. We pointed out their nutraceutical importance such as their proteins, peptides, polysaccharides, lipids, polyphenolic compounds pigments, marine enzymes, minerals, and vitamins. Their pharmacological activities include antimicrobial, anticancer, antioxidant, anti-inflammatory, and analgesic activities. Moreover, certain molluscs like abalones and mussels contain unique compounds with potential medicinal applications, ranging from wound healing to anti-cancer effects. Understanding the nutritional and therapeutic value of marine molluscs highlights their significance in both pharmaceutical and dietary realms, paving the way for further research and utilization in human health. [ABSTRACT FROM AUTHOR]

The Iberian Peninsula is the ideal setting for the study of the use of marine resources in the Mesolithic and Neolithic periods. Previous studies have focused on specific geographical areas and on a single chronological period. Instead, we offer here a synthesis of the peninsula covering a broad period of time, thus allowing a study of the role of marine resources in the Neolithisation process. Published data on the exploitation of marine molluscs from 59 archaeological levels, close to the coast and dated between 10,400 and 4650 cal BP, in the Iberian Peninsula are reviewed in order to examine the change that occurred in the consumption of marine resources following the introduction of domestic plants and animals. The analysis of the composition and diversity of assemblages collected at each site has allowed us to identify specialisation in the management strategy of marine molluscs during the Neolithic. Regional variability in the diversity of species collected, particularly in the Cantabrian region, where there is continuity in the management of molluscs between the Mesolithic and Neolithic periods, could be linked to the pace at which agriculture and animal husbandry were adopted. In short, together with environmental factors, the establishment of farming practices may have had a slight impact on the specialisation in the management of coastal environments. [ABSTRACT FROM AUTHOR]

Marine molluscs are of enormous scientific interest due to their astonishing diversity in terms of their size, shape, habitat, behaviour, and ecological roles. The phylum Mollusca is the second most common animal phylum, with 100,000 to 200,000 species, and marine molluscs are among the most notable class of marine organisms. This work aimed to show the importance of marine molluscs as a potential source of nutraceuticals as well as natural medicinal drugs. In this review, the main classes of marine molluscs, their chemical ecology, and the different techniques used for the extraction of bioactive compounds have been presented. We pointed out their nutraceutical importance such as their proteins, peptides, polysaccharides, lipids, polyphenolic compounds pigments, marine enzymes, minerals, and vitamins. Their pharmacological activities include antimicrobial, anticancer, antioxidant, anti-inflammatory, and analgesic activities. Moreover, certain molluscs like abalones and mussels contain unique compounds with potential medicinal applications, ranging from wound healing to anti-cancer effects. Understanding the nutritional and therapeutic value of marine molluscs highlights their significance in both pharmaceutical and dietary realms, paving the way for further research and utilization in human health.

The exploitation of marine molluscs during the Middle and Upper Palaeolithic is a topic that has been extensively investigated over the last few years, shedding light on human adaptation in coastal environments. However, such studies mainly focus on the role of marine molluscs in the subsistence practices of the hunter-fisher-gatherers of the Mediterranean Basin.Although small, non-dietary gastropods found in archaeological deposits have the potential to provide important clues regarding past human activities, their role is still little investigated. This research explores the question of whether taphonomy could be useful for the interpretation of these less conspicuous “incidental” shell remains found in archaeomalacological assemblages.In this paper we present the results of a taphonomic study carried out on a total of 314 Bittium shells recovered in the Mousterian and Protoaurignacian levels of Riparo Bombrini, a collapsed rockshelter in the Balzi Rossi Palaeolithic site complex (NW Italy). How did these small, non-dietary gastropods come to be deposited? Are they an unintentional by-product of certain harvesting techniques, or the result of a deliberate gathering? Or, could natural factors be responsible for their presence at the site? To answer these questions, different types of taphonomic processes were considered. Comparing the Bombrini archaeomalacological remains and modern shells accumulated on beaches leads us to propose that the most likely cause of their presence at the site is a correlation between Bittium shells and small sea pebbles, rather than the accidental transport of these shells with algae and seagrasses that could have been brought back to the site.

Chitons (Polyplacophora) are marine molluscs that mostly inhabit rocky intertidal shores. Their biological and phylogenetic studies are comparatively sparse in the western Indo-Pacific regions. In addition, chitons belonging to the subfamily Acanthopleurinae Dall, 1889, collected from the Andaman Sea of the northeastern Indian Ocean and the Jizan coast of Saudi Arabia were sequenced and analyzed to study the phylogenetic affinities. The analysis was carried out using a single locus dataset (cytochrome oxidase 1) generated during the present study and integrated with sequences retrieved from GenBank. Acanthopleura gemmata (Blainville, 1825) from India was linked to Acanthopleura vaillantii Rochebrune, 1882, from the Saudi Arabia coast. Squamopleura miles (Carpenter in Pilsbry, 1893) from the Indian coast forms a separate clade representing the genus. Furthermore, the results illustrate several significant instances of misplacement of several species under the wrong genus and the existence of cryptic species within the genera Acanthopleura and Squamopleura. An integrated approach is required to better understand these important intertidal groups' taxonomy, systematics, and biogeography. [ABSTRACT FROM AUTHOR]

Eight marine gastropod records were recorded from the north west of the Arabian Gulf, Iraqi coast during March 2020. The species are Turritella cochlea Reeve, 1849 (family Turritellidae), Rhinoclavis fasciata (Bruguière, 1792) (family Cerithiidae), Semiricinula tissoti (Petit de la Saussaye, 1852) (family Muricidae), Ancilla castanea (G. B. Sowerby I, 1830) (family Ancillariidae), Bulla ampulla Linnaeus, 1758 (family Bullidae), Oliva bulbosa (Röding, 1798) (family Olividae), Naria turdus (Lamarck, 1810) and Erronea caurica quinquefasciata (Röding, 1798) (family Cypraeidae). These records raise the number of marine gastropods from the Iraqi coast to 40 species. [ABSTRACT FROM AUTHOR]

Eight marine gastropod records were recorded from the north west of the Arabian Gulf, Iraqi coast during March 2020. Th e species are Turritella cochlea Reeve, 1849 (family Turritellidae), Rhinoclavis fasciata (Bruguière, 1792) (family Cerithiidae), Semiricinula tissoti (Petit de la Saussaye, 1852) (family Muricidae), Ancilla castanea (G. B. Sowerby I, 1830) (family Ancillariidae), Bulla ampulla Linnaeus, 1758 (family Bullidae), Oliva bulbosa (Röding, 1798) (family Olividae), Naria turdus (Lamarck, 1810) and Erronea caurica quinquefasciata (Röding, 1798) (family Cypraeidae). Th ese records raise the number of marine gastropods from the Iraqi coast to 40 species.

Defensive chemicals are used by plants and animals to reduce the risk of predation through different mechanisms, including toxins that cause injury and harm (weapons) and unpalatable or odiferous compounds that prevent attacks (deterrents). However, whether effective defences are both toxins and deterrents, or work in just one modality is often unclear.In this study, our primary aim was to determine whether defensive compounds stored by nudibranch molluscs acted as weapons (in terms of being toxic), deterrents (in terms of being distasteful) or both. Our secondary aim was to investigate the response of different taxa to these defensive compounds.To do this, we identified secondary metabolites in 30 species of nudibranch molluscs and investigated their deterrent properties using antifeedant assays with three taxa: rock pool shrimp, Palaemon serenus, and two fish species: triggerfish Rhinecanthus aculeatus and toadfish Tetractenos hamiltoni. We compared these results to toxicity assays using brine shrimp Artemia sp. and previously published toxicity data with a damselfish Chromis viridis.Overall, we found no clear relationship between palatability and toxicity, but instead classified defensive compounds into the following categories: Class I & II—highly unpalatable and highly toxic; Class I—weakly unpalatable and highly toxic; Class II—highly unpalatable but weakly toxic; WR (weak response)—weakly unpalatable and weakly toxic. We also found eight extracts from six species that did not display activity in any assays indicating they may have very limited chemical defensive mechanisms (NR, no response). We found that the different classes of secondary metabolites were similarly unpalatable to fish and shrimp, except extracts from Phyllidiidae nudibranchs (isonitriles) that were highly unpalatable to shrimp but weakly unpalatable to fish.Our results pave the way towards better understanding how animal chemical defences work against a variety of predators. We highlight the need to disentangle weapons and deterrents in future work on anti‐predator defences to better understand the foraging decisions faced by predators, the resultant selection pressures imposed on prey and the evolution of different anti‐predator strategies. [ABSTRACT FROM AUTHOR]

Aim: A large body of ecological theory predicts that non‐indigenous species (NIS) are successful invaders if their niches overlap little with native taxa. Native–non‐indigenous trait dissimilarity, however, may also be observed if NIS have outcompeted ecologically similar native species. Discriminating these scenarios is essential for assessing invasion impacts but requires baseline assemblage data that are frequently unavailable. We overcome this impediment by analysing death assemblages – identifiable organism remains in the seafloor – which are natural community archives. Focusing on molluscs from the heavily invaded Eastern Mediterranean, we gain insights into the contentious role of competitive displacement by NIS as the primary driver of the massive regional declines of native populations, and their potential to alter ecosystem functioning. Location: Israel/Eastern Mediterranean. Time period: Pre‐Lessepsian invasion (pre‐1869) to contemporary. Major taxa studied: Mollusca. Methods: We sampled molluscan living and death assemblages from various substrates on the Israeli shelf and compiled trait information on all constituent species. We then compared the abundance‐weighted trait composition and functional diversity of native and non‐indigenous assemblage components. Death assemblage time‐coverage was quantified radiometrically. Results: Native and non‐indigenous assemblage components consistently differed in trait composition, both in present‐day (i.e., living) and historical (i.e., death) assemblages, irrespective of habitat conditions. Furthermore, present‐day non‐indigenous assemblage components had a different trait composition than historical native assemblages. These findings suggest that the increasing NIS dominance has considerably altered the functional properties of shallow‐water molluscan assemblages. Main conclusions: By utilizing death assemblages, we show that native and non‐indigenous assemblage components have differed in trait composition since the onset of the invasion, suggesting that competition was unlikely the primary driver of the regional‐scale native biodiversity loss. Our findings, however, also imply that NIS cannot functionally compensate for native species disappearance. Instead, the transition towards increasingly NIS‐dominated assemblages has profoundly altered ecosystem functioning, with unknown consequences. [ABSTRACT FROM AUTHOR]

Chitons (Polyplacophora) are marine molluscs that mostly inhabit rocky intertidal shores. Their biological and phylogenetic studies are comparatively sparse in the western Indo-Pacific regions. In addition, chitons belonging to the subfamily Acanthopleurinae Dall, 1889, collected from the Andaman Sea of the northeastern Indian Ocean and the Jizan coast of Saudi Arabia were sequenced and analyzed to study the phylogenetic affinities. The analysis was carried out using a single locus dataset (cytochrome oxidase 1) generated during the present study and integrated with sequences retrieved from GenBank. Acanthopleura gemmata (Blainville, 1825) from India was linked to Acanthopleura vaillantii Rochebrune, 1882, from the Saudi Arabia coast. Squamopleura miles (Carpenter in Pilsbry, 1893) from the Indian coast forms a separate clade representing the genus. Furthermore, the results illustrate several significant instances of misplacement of several species under the wrong genus and the existence of cryptic species within the genera Acanthopleura and Squamopleura. An integrated approach is required to better understand these important intertidal groups’ taxonomy, systematics, and biogeography.

Biological fitness relies on processes acting at various levels of organization, all of which can be modified by environmental change. Application of synthesis frameworks, such as the Adverse Outcome Pathway (AOP), can enhance our understanding of the responses to stressors identified in studies at each level, as well as the links among them. However, the use of such frameworks is often limited by a lack of data. In order to identify contexts with sufficient understanding to apply the AOP framework, we conducted a meta-analysis of studies considering ocean acidification effects on calcifying mollusks. Our meta-analysis identified that most studies considered the adult life history stage, bivalve taxonomic group, individual-level changes, and growth- and metabolism-related responses. Given the characteristics of the published literature, we constructed an AOP for the effects of ocean acidification on calcification in an adult bivalve, specifically the Pacific oyster (Magallana gigas). By structuring results within the AOP framework, we identify that, at present, the supported pathways by which ocean acidification affects oyster calcification are via the downregulation of cavortin and arginine kinase transcription. Such changes at the molecular level can prompt changes in cellular and organ responses, including altered enzyme activities, lipid peroxidation, and regulation of acid–base status, which have impacts on organism level metabolic rate and, therefore, calcification. Altered calcification may then impact organism mortality and population sizes. We propose that when developed and incorporated in future studies, the AOP framework could be used to investigate sources of complexity including varying susceptibility within and among species, feedback mechanisms, exposure duration and magnitude, and species interactions. Such applications of the AOP framework will allow more effective reflections of the consequences of environmental change, such as ocean acidification, on all levels of biological organization.

Spatial subsidies are associated with pronounced ecosystem responses, as nutrients cross ecological boundaries and cascade through food webs. While the importance of subsidies is known, the role of shellfish, specifically molluscs, as a marine subsidy has not been formally described. Focusing primarily on the Pacific coast of North America, we identify vectors that transport shellfish‐derived nutrients into coastal terrestrial environments, including birds, mammals, and over 13 000 yr of marine resource use by people. Evidence from recipient ecosystems suggests shellfish drastically influence soil chemistry, forest productivity and the diversity of primary producers at the regional and landscape level. Responses in higher trophic levels have not yet been investigated, but given documented responses in lower trophic levels, this may be due to a lack of examination. To determine if the processes we describe within the northeast Pacific are pertinent to coastal environments worldwide, we also explore shellfish subsidies globally, with a specific focus on temperate and tropical islands. As shellfish are not as spatially or temporally constrained as other subsidies, our examination suggests our findings are applicable to many other geographical regions along the marine–terrestrial interface. [ABSTRACT FROM AUTHOR]

Analysis of over 4000 complete left oyster valves from late medieval and post-medieval Dudley Castle reveals the changing role of this perishable luxury over a 700-year period. Throughout the occupation, it seems that oysters were used as ingredients rather than served raw in the shell. A greater reliance on oyster consumption is apparent in the later fourteenth century, perhaps reflecting a more diverse diet amongst the aristocracy in the wake of the Black Death. An increased preference for mussels and whelks is also attested in the Tudor and early modern periods, reflecting changing perceptions of these foods. Overall, it is likely that natural beds were exploited throughout the time that oysters were being brought to Dudley Castle; however, the evidence demonstrates a shift from limited exploitation of natural inter-tidal sources in the eleventh century towards the dredging of sub-littoral beds in later periods, with some possible translocation of oyster stock. Changes in the shape, size and appearance of the oyster shells suggest the source locales from which the oysters derived changed through time. A notable shift occurred in the fourteenth century, which could reflect changes in supply brought about by altered tenancy at Dudley Castle and/or disruptions to trade brought about by the Black Death. Future biochemical analyses are recommended to provide greater clarity on the origin of those sources. [ABSTRACT FROM AUTHOR]

For over 120 years, the shell middens of western Scotland and the series of open-air sites on Oronsay have been the focus of debate in European Mesolithic studies. This paper challenges the significance of Oronsay in light of results from the geophysical survey and test-excavation of a new limpet and periwinkle shell midden dated to the late 5th or start of the 4th millennium cal bc at Port Lobh, Colonsay that offers fresh evidence to re-evaluate critically the role of Oronsay and coastal resources in island settlement models ahead of the Mesolithic–Neolithic transition. Test excavations recovered a marine molluscan assemblage dominated by limpet and periwinkle shells together with crab, sea urchin, a fishbone assemblage composed mainly of Gadidae, some identifiable bird and mammal bone, carbonised macroplant remains, and pumice as well as a bipolar lithic assemblage and coarse stone implements. Novel seasonality studies of saithe otolith thin-sections suggest wintertime tidal fishing practices. At least two activity events may be discerned, dating from the late 5th millennium cal bc. The midden could represent a small number of rapidly deposited assemblages or maybe the result of stocastic events within a more extended timeframe. We argue that alternative research questions are needed to advance long-standing debates about seasonal inter-island mobility versus island sedentism that look beyond Oronsay to better understand later Mesolithic occupation patterns and the formation and date of Oronsay middens. We propose alternative methodological strategies to aid identification of contemporaneous sites using geophysical techniques and lithic technological signatures. [ABSTRACT FROM AUTHOR]

Biomineralization refers to the dynamic physiological processes whereby living organisms elaborate mineralized tissues. The existence of extremely abundant molluscan species shows the diversity of mineralized tissues, since the majority of them (Conchifera) produce shells that vary in size and shape. Over the past decades, great progress has been made on the study of the cellular biology of shell biomineralization. The construction of the molluscan shell is the archetype of biologically controlled mineralization which requires specialized cellular machinery. It has been so far demonstrated that the cells involved in shell formation come from two different sources: outer mantle epithelial cells (OME) and circulating hemocytes. OMEs secrete the organic matrix, among which shell matrix proteins (SMPs) determine mineralogical and crystallographic properties of shell. Circulating hemocytes take part in the deposition of intracellular biominerals and deliver them to the mineralization sites. Many novel SMPs have been identified by using molecular biology techniques (i.e., gene cloning, in situ hybridization, immunohistochemistry) coupled with high-throughput sequencing data (genome, proteome, secretome and transcriptome), and their corresponding functions during the shell formation have also been confirmed. The cellular activity of OME and hemocytes during shell formation are significantly increased during shell regeneration process. A potential cellular basis model for molluscan shell formation is proposed. The shell matrix proteins, mostly secreted from OME, and a few secreted from hemocytes or other organs, are either directly delivered to the mineralization site via exosome or classical secretory pathway, or first transported to the hemolymph, and then engulfed by hemocytes (mainly granulocytes), which will disintegrate and release shell proteins and CaCO3 crystals at the mineralization front. OME and hemocytes may also be involved in the nucleation and remodeling process of CaCO3 mineral. These cells and cell products work co-operatively to produce an organo-mineral shell, which is composed of various biomineral ultra-structures and macromolecular organic components.

Marine molluscs are consumed as culinary delicacies and represent a relatively untapped source of natural functional food ingredients. The bioactive potential of ethyl acetate-methanol (C2H5OAc/CH3OH) extract of molluscs Uroteuthis duvaucelii, Amphioctopus marginatus, Crassostrea madrasensis, and Sepiella inermis were demonstrated using different in vitro systems. The C2H5OAc/CH3OH extract of A. marginatus displayed greater 2, 2-diphenyl-1-picryl-hydrazil (IC90 1.76 mg mL−1) radical quenching capacity along with potential hydroxymethylglutaryl coenzyme-A reductase (HMGCR)-inhibiting activity (IC90 1.21 mg mL−1) and angiotensin converting enzyme-I inhibitory property (ACE-I) (IC90 0.87 mg mL−1) compared to those displayed by other molluscs. The organic extract of S. inermis set forth significantly higher pro-inflammatory 5-lipoxygenase inhibitory property (IC90 1.96 mg mL−1) along with potential antidiabetic activity as determined by dipeptidyl peptidase-4 (DPP-4) antagonistic activities (IC90 2.62 mg mL−1, P <.05). Significant correlations were observed between bioactive properties and electronegative groups of organic extracts of a mollusc. The free radical quenching property of the extracts exhibited a positive correlation towards other bioactivities, implicating the role of antioxidant property of the compounds in the extract to inhibit lifestyle ailments. The present study indicated that S. inermis and A. marginatus could be utilized as functional food ingredients to combat hypertension, hyperlipidemia, and inflammation-related risks. [ABSTRACT FROM AUTHOR]

Abstract Polychlorinated biphenyls (PCBs) found in marine molluscs could be a serious threat to the health of consumers; however, studies on this subject are limited. To understand this threat, the indicator PCBs (PCB-28, PCB-52, PCB-101, PCB-118, PCB-138, PCB-153 and PCB-180) found in six different kinds of molluscs were determined, and the associated cancer risk for consumers that intake these indicator PCBs via molluscs was assessed. The total concentrations of PCBs in molluscs ranged from 17.51 to 47.43 ng/g (d.w.). The order of contamination levels for indicator PCBs in molluscs was Perna viridis > Ruditapes philippinarum > Crassostrea gigas > Mimachlamys nobilis > Glossaulax didyma > Anadara antiquata. Tri-, tetra- and penta-PCBs were the dominant congeners in molluscs from Haikou City. Tetra-PCBs are the most common PCB, accounting for 38.49% of total PCBs. Compared with previous global studies on PCBs in molluscs, the pollution level of indicator PCBs in the molluscs from Haikou City was lower than most of reports in Europe and China, but higher than those from France and Korea, suggesting a moderate pollution level. The 50% and 95% cancer risks of indicator PCBs in molluscs for adult consumers were 2.75 × 10−7 and 4.32 × 10−7, indicating that the cancer risk was at an acceptable level. Since the dioxin like-PCBs were not analyzed in this study, the cancer risk of PCBs to human health might be underestimated; therefore, more studies on PCB pollution in molluscs are required. Graphical abstract Unlabelled Image Highlights • Tri-, tetra- and penta-PCBs were the dominant congeners in molluscs. • Pollution level of indicator PCBs in studied molluscs was at a moderate level. • Cancer risk of indicator PCBs for consumers was at an acceptable level. [ABSTRACT FROM AUTHOR]

Previously unpublished oxygen isotope ratios have been obtained from the opercula of marine molluscs (Turbo sarmaticus) from Klasies River Cave deposits (excavated initially by Singer and Wymer, subsequently by Deacon, and most recently byWurz), on the southern coast of South Africa. The late Pleistocene samples are associated with anatomically modern human remains and Middle Stone Age (MSA) technologies: MSA I, II, Howieson’s Poort and MSA III. The oxygen isotope ratios presented in this study of more than 30 opercula supplement data obtained by Shackleton and by Loftus et al. In the context of available dates, MSA I samples relate to relatively warm conditions and high sea levels in parts of Marine Isotope Stage (MIS) 5. The Rockfall Member (RF) between MSA II and Howieson’s Poort deposits may correspond to MIS 4 when sea levels and global temperatures were relatively low. The Howieson’s Poort isotope data are not inconsistent with Shackleton’s view that the Howieson’s Poort deposits include at least part of MIS 3. This study suggests that part of the Howieson’s Poort relates to the warmest period of MIS 3. Younger MSA III samples in MIS 3 are associated with cooler conditions and lower sea levels. [ABSTRACT FROM AUTHOR]

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• New data for shell mineralogy and chemistry of 27 Arctic gastropod species. • Shell chemical composition of gastropods differed in species-related pattern. • Correlation between metals concentration and size observed in certain species. • Environmental factors can shape shell chemistry to a lesser degree than biology. Assessment of environmental controls and natural variability of shell chemistry is inevitable to understand the future of marine calcifiers functioning under the climate change and acidification scenarios. Here we document mineralogical and chemical composition (Al/Ca, Ba/Ca, Fe/Ca, Mg/Ca, Mn/Ca, Na/Ca, P/Ca, S/Ca, Sr/Ca and Zn/Ca ratios) of shells of 27 gastropod species collected in four Arctic and sub-Arctic coastal localities. Most examined gastropods had purely aragonitic shells, although three species were characterized by bimineralic mineralogy, with calcite forming the external shell layer. Positive relationship between shell size and proportion of calcite in bimineralic gastropods indicated that older specimens could possess a thicker outer shell layer of calcite than did younger individuals. Statistically significant differences in shell chemical composition were found among species irrespective of the sampling location, suggesting that organisms exerted a biological control on elements uptake and retention. Extrinsic factors (mostly seawater temperature, seawater and sediment metals concentrations) contributed to elements uptake to a lesser degree. Thus, the observed differences in shell elements' concentrations among gastropod species can be driven by both factors: species-specific selective incorporation of elements into shells and bioavailability of those elements in the ambient environment. [ABSTRACT FROM AUTHOR]

An exceptional species richness for Mollusca was found on Avempace bank (349-365 m), Djibouti group, Alboran Sea, where the most abundant species was the crinoid Leptometra phalangium. A sample of sediment sieved on a 0.5-mm mesh yielded 156 species of molluscs (83 live-taken, 1772 specimens) with a high Shannon-Wiener diversity index (H’(log2)=3.60). The dominant mollusc was Limopsis aurita and the six most common species accounted for 77% of the specimens. On the other hand, 42 species were represented by only one or two specimens. Two species are described as new, three more are first findings in the Mediterranean and two are first findings in Iberian waters. One-third of the species have not been reported from the neighbouring, well-explored Alboran Island platform. There is a considerable balance between the trophic groups, denoting a stable and structured community. Most of the species have an extensive Atlantic range, and most have a planktonic larval stage. Therefore, it can be hypothesized that the fauna benefits from a diverse influx of larvae carried in by the more superficial incoming Atlantic current. Because of its exceptional richness, this type of bathyal community with Leptometra and Limopsis should be considered a high priority for habitat conservation in the Mediterranean deep sea.

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. [ABSTRACT FROM AUTHOR]

Surveys conducted at Niau, a slightly raised atoll in the Tuamotu Archipelago, revealed a brackish community with only a few extant species of fishes, crustaceans and molluscs in the residual semi-enclosed lagoon. Dredging of superficial sediments near the Niau lagoon resulted in a rich shell mollusc assemblage with 120 species, dating from the Pleistocene Last Interglacial Maximum (120,000 years BP). The assemblage contains 3 previously described new species, collected nowhere else since, and 12 species locally extinct but extant in the Indo-Pacific. Results are compared with previous studies on Pleistocene reefs of the Indo-Pacific. [ABSTRACT FROM AUTHOR]

Bone metabolism is a physiological process that maintains the skeletal integrity and bone functions. Skeletal integrity is always balanced by two key cell types—bone resorbing osteoclasts and bone-forming osteoblasts. Imbalance between generation and function of osteoclasts and osteoblasts often leads to pathological conditions such as osteoporosis, osteopetrosis, Paget's disease. Osteoporosis is one of the most common age-related diseases characterized by decreased bone mineral density and microarchitectural deterioration. Current therapies are indeed effective in preventing bone loss but are also followed by side effects. Since many years, marine organisms have been considered as a good source of bioactive molecules or compounds with potential pharmaceutical properties. Marine Natural Products (MNPs) derived from various marine resources such as marine cyanobacteria, dinoflagellates, algae, sponges, soft corals, molluscs, fishes, and mangroves had shown profound effect on bone metabolism through inhibiting osteoclastogenesis and up-regulating osteoblastogenesis via modulating RANK/RANKL/OPG pathway. Amongst the pre-clinically investigated MNPs for management of osteoporosis, very few are under phase I clinical trials. This review discusses the currently available pharmacological drugs and there major health concern in osteoporosis treatment. It further gives an insight into various marine resources and marine-derived bioactive products, depicting their mechanism of action, functional role, and how these can be exploited for the treatment of osteoporosis.

Warning signal variation is ubiquitous but paradoxical: low variability should aid recognition and learning by predators. However, spatial variability in the direction and strength of selection for individual elements of the warning signal may allow phenotypic variation for some components, but not others. Variation in selection may occur if predators only learn particular colour pattern components rather than the entire signal. Here, we used a nudibranch mollusc, Goniobranchus splendidus, which exhibits a conspicuous red spot/ white body/yellow rim colour pattern, to test this hypothesis. We first demonstrated that secondary metabolites stored within the nudibranch were unpalatable to a marine organism. Using pattern analysis, we demonstrated that the yellow rim remained invariable within and between populations; however, red spots varied significantly in both colour and pattern. In behavioural experiments, a potential fish predator, Rhinecanthus aculeatus, used the presence of the yellow rims to recognize and avoid warning signals. Yellow rims remained stable in the presence of high genetic divergence among populations. We therefore suggest that how predators learn warning signals may cause stabilizing selection on individual colour pattern elements, and will thus have important implications on the evolution of warning signals. [ABSTRACT FROM AUTHOR]

Intertidal mussels, limpets and oysters have been utilized as food by the prehistoric inhabitants of South African coastal regions since at least the Last Interglacial (130 ka). There is, however, little current information on their macronutrient content and nutritional value. In this paper, I present new, quantitative information on the protein, fat and energy content of two limpet and one mussel species from the Atlantic west coast ( Cymbula granatina , Scutellastra granularis and Choromytilus meridionalis ) and one mussel, one oyster and one limpet species from the northern coast of KwaZulu-Natal ( Perna perna, Saccostrea culcullata and Patella concolor ). The results of nutrient analyses show that many of these shellfish contain relatively large amounts of protein, fat and energy. When discussed alongside patterns in the archaeological record, these findings have important implications for our understanding of coastal foraging during the Middle Stone Age. Nutritional information and archaeological evidence indicate that simple marine molluscs were a significant source of protein and, to a lesser extent, energy, for the prehistoric inhabitants of the Atlantic west coast. In contrast, despite the good macronutrient returns of some species, shellfish were not a significant source of protein or energy for the Middle Stone Age occupants of Sibudu Cave in KwaZulu-Natal. [ABSTRACT FROM AUTHOR]

The marine gastropod superfamily Triphoroidea is composed of three families: Triphoridae and Cerithiopsidae are usually associated with shallow waters, and Newtoniellidae is historically associated with the deep sea. We provide an extensive review of the literature and delineate the groups within the three families that are truly linked to the deep sea, with reference to their developmental mode. Two genera of Triphoridae,StrobiligeraandInella, are commonly found in deep waters, andMetaxiapresents some species with apparently wide depth ranges. Some deep-sea genera currently placed in Cerithiopsidae, such asEktonosandKrachia, are very similar to Newtoniellidae; a phylogeny of the superfamily is needed to clarify the distinction of the two families. The majority of Triphoroidea species from the deep sea undergo non-planktotrophic development, although planktotrophy is not uncommon. [ABSTRACT FROM AUTHOR]

This study provided new data on shell mineralogy in 23 Arctic bivalve species. The majority of examined species had purely aragonitic shells. Furthermore, we measured concentrations of Al, Ba, Ca, Fe, K, Mg, Mn, Na, P, S, Sr and Zn in 542 shells representing 25 Arctic bivalve species. Species-related differences in concentrations of specific elements were significant and occurred regardless of locations and water depths. This observation implies the dominance of biological processes regulating elemental uptake into the skeleton over factors related to the variability of abiotic environmental conditions. Analysis of the present study and literature data revealed that the highest concentrations of metals were observed in bivalves collected in the temperate zone, with intermediate levels in the tropics and the lowest levels in polar regions. This trend was ascribed mainly to the presence of higher anthropogenic pressure at temperate latitudes being a potential source of human-mediated metal pollution. • New data for shell mineralogy and chemical composition of 25 Arctic bivalve species • Species-specific differences in concentrations of elements in Arctic bivalve shells • Aragonite as a main shell CaCO 3 polymorph regardless geographical location • The highest shell concentrations of metals in temperate bivalve species • Anthropogenic pressure as a main source of metal pollution in temperate latitudes [ABSTRACT FROM AUTHOR]

This review focuses on defensins and cystein rich peptides, which are the most abundant natural antimicrobial peptides (AMPs) described in molluscs. These are compact peptides, 3-5 kDa in molecular mass, cationic and amphipatic; the presence of at least six cysteine residues forming three or four disulfide bridges is their prime structural characteristic. A 3-D structural characterization of these molecules has been included in recent investigations, using currently-available techniques. AMPs have been purified from hemocytes, epithelial tissue and plasma as well as cloned and chemically synthesized. Their antibacterial activity against Gram-positive and Gram-negative bacteria and fungi has been shown; only a synthetic mytilin fragment has displayed activity against viruses.

Gadila elongata comb. nov. was described in 1920 from the northern Gulf of Mexico. Until recently, it was only known from the type locality. Herein we present the first record of G. elongata from Brazil (Northeast coast, Ceará state, collected at 177 m) and a morphometrics analysis of the Brazilian species of Gadila. A multivariate Discriminant Function Analysis, based on nine shell morphometric variables (length, maximum diameter, length to maximum diameter ratio, distance of point of maximum diameter from anterior aperture, maximum curvature, anterior aperture height to anterior aperture width ratio, apical aperture height, apical aperture width and apical aperture height to apical aperture width ratio) enabled the distinction between all species studied. Comparisons of shell morphometrics show that length and length to maximum diameter ratio are the most important variables in the differentiation of Gadila species.

There is increasing evidence that humans have exploited intertidal and shallow-water species for much longer than has been previously considered, and certainly not restricted to Anatomically Modern Humans (AMH). One of the principal reasons for the lack of evidence up till recently has been a lack of consideration for the temporal and spatial backdrop to such activities throughout human evolution, in particular related to changes in sea-level during the Pleistocene (Bailey et al., 2008). This study reports on the marine molluscs excavated from Gorham's Cave between 1998 and 2005, focussing in particular between levels III and IV, corresponding to the Upper (AMH) and Middle Palaeolithic (Neanderthals), respectively. Given that Gorham's Cave was never more than approximately 2 km away from the coastline, it still preserves evidence of exploitation of marine molluscs for food by Neanderthals and in this article the data obtained are compared across the Middle–Upper Palaeolithic transition. The results obtained suggest a high degree of consistency in the mode of marine mollusc exploitation between levels, and comparisons with extant communities supports the contention that marine molluscs were exploited in direct proportion to their relative abundance and accessibility. Patterns in shell size distributions for some of the main species exploited are discussed, as are possible anthropic valve selection and the marine climatic signals that can be extracted from such data. The main difference that emerges between Upper and Middle Palaeolithic levels was a lack of evidence of collection for decoration in Middle Palaeolithic levels, but even here the relatively small size of the Level IV sample precluded totally excluding this possibility based only on absence of evidence. [ABSTRACT FROM AUTHOR]

The case study of Yves Bay (Pertuis Charentais, France) highlighted links between environmental gradients ( i.e. sediment characteristics and emersion time) and prey distribution and availability for the two most numerous shorebird species overwintering in Yves Bay: the red knot Calidris canutus and the dunlin Calidris alpina . Two hundred and fifty-two stations were sampled on a predetermined 250 m regular grid covering the intertidal mudflats of this major wintering site in France for east-Atlantic migratory shorebirds. The distribution of principal benthic species abundance and biomass was modelled along two environmental gradients: sediment structure (particularly pronounced north–south sand-mud gradient) and emersion time. The effect of emersion time combined with sedimentary structure strongly explained abundances and biomasses of the main prey for C. canutus and C. alpina in the bay ( Cerastoderma edule, Hydrobia ulvae , Macoma balthica , Scrobicularia plana , and Nephtys hombergii) . This study highlighted prey species-specific spatial segregation/overlapping as well as spatial interferences in the trophic niche of the two shorebirds. [ABSTRACT FROM AUTHOR]

Complete lectin mapping of molluscs with their diversified recognition pattern and possible role in lectin-carbohydrate interaction based immune response triggering need much attention. In this communication, Gal/GalNAc specific three lectins AGL-IA ( Anadara granosa lectin-IA), AGL-IB ( A . granosa lectin-IB) and AGL-IV ( A . granosa lectin-IV) and a lectin having hemolytic activity AGL-III ( A. granosa lectin-III) were purified from the plasma of A. granosa bivalve by a combination of gel filtration and affinity chromatography. AGL-IA and IB were oligomeric lectins whereas, AGL-III and IV were monomeric. The molecular weight of AGL-IA, IB, III and IV were 375, 260, 45 and 33 kDa respectively. AGL-IA and IV agglutinated both rabbit and pronase treated human erythrocytes, whereas AGL-IB agglutinated only rabbit erythrocytes. AGL-III was found to agglutinate rabbit erythrocytes, however, it caused hemolysis of pronase treated human erythrocytes. The activity of all four lectins was calcium dependent and maximum at a pH range 7–8. Apart from Gal/GalNAc specific, the four lectins showed substantial differences in their carbohydrate recognition pattern. Moreover, there was a difference in the carbohydrate specificity between AGL-III and other three lectins (AGL-IA, AGL-IB and AGL-IV) towards polyvalent glycotope. On the one hand, ‘cluster glycoside effect’ i.e ., an enhancement of the activity of a multivalent ligand, was observed for carbohydrate specificities of AGL-IA, AGL-IB, AGL-IV. On the other hand, the effect of multivalent ligands on the carbohydrate specificity of AGL-III was opposite of cluster glycoside effect. The affinity of AGL-IA, AGL-IB and AGL-IV for ligands can be ranked as follows: glycoproteins >> polysaccharide > oligosaccharides and monosaccharides. However, Gal related monosaccharides were the best inhibitors of AGL-III and the inhibitory activity decreased gradually in the following order: monosaccharide > disaccharide > polysaccharide. Thus, the diverse specificity of multiple lectins in A. granosa plasma possibly enables to recognize a wide range of microorganisms. [ABSTRACT FROM AUTHOR]

Pampean creeks were evaluated in the present study as potential land-based sources of PCB marine contamination. Different carbon and nitrogen sources from such creeks were analysed as boosters of PCB bioaccumulation by the filter feeder bivalve Brachidontes rodriguezii and grazer limpet Siphonaria lessoni . Carbon of different source than marine and anthropogenic nitrogen assimilated by organisms were estimated through their C and N isotopic composition. PCB concentration in surface sediments and mollusc samples ranged from 2.68 to 6.46 ng g −1 (wet weight) and from 1074 to 4583 ng g −1 lipid, respectively, reflecting a punctual source of PCB contamination related to a landfill area. Thus, despite the low flow of creeks, they should not be underestimated as contamination vectors to the marine environment. On the other hand, mussels PCB bioaccumulation was related with the carbon source uptake which highlights the importance to consider this factor when studying PCB distribution in organisms of coastal systems. [ABSTRACT FROM AUTHOR]

Neanderthal retouched tools made of marine shells have been reported in several sites in southern peninsular Europe. They are an adaptation to the coastal marine environment. Most important are the non-lithic tools that mark Mediterranean technical behaviour. Tool production is related to human needs, available resources, technical and social knowledge and innovation. The wide diffusion of shell tools makes them interesting items for investigating the variability of technology and contact among Neanderthal groups. Although these tools were first identified in the last 1950s, they still have not been considered in sufficient detail. In particular, this technology is handicapped by the lack of detailed description and references for technological analysis. This research proposes an original method aimed at reconstructing the process of production and use of these tools. It was conceived for future comparisons, both between shell tool assemblages and between lithic and shell tools, creating a common vocabulary and a set of analytical principles borrowed from lithic analysis, with which to think systematically beyond single cases. The analytical method is organised in five parts: taxonomy, morphometrical analysis, technical analysis of the retouched cutting edge, taphonomy and experimental archaeology. Thereafter, we present data on the shell tools of Grotta del Cavallo, coming from a recent excavation in layer L. It is the first detailed case study of Neanderthal non-lithic artefacts, applied to an assemblage with a significant number of well-preserved elements and with a certain stratigraphic context, and represents a constructive framework for the knowledge of the local adaptation to this raw material and of variability of Neanderthal technical behaviour. [ABSTRACT FROM AUTHOR]

The first description of the fauna of shell-bearing gastropod from chemosynthesis-based communities of the Bering Sea is given. The work includes materials collected during the cruises of the RV Akademik M.A. Lavrentyev in 2016 and 2018 in two types of the reducing biotopes: hydrothermal fields on the underwater Piip Volcano and the methane seeps on the Koryak slope of the Bering Sea. The Piip Volcano (∼ 368–495 m) is the northernmost (55°22' – 55°24' N) hydrothermal region in the Pacific. Methane seep fields of the Koryak slope found between 400 and 700 m depth are the northernmost chemosynthesis-based habitats known to date in the Pacific (60°49–61°10). In total, 27 recognizible taxonomic units (RTUs) of shell-bearing gastropods were identified from both areas, at least six of them presumably belong to species new to science. Also, five species are new to the fauna of the Bering Sea and adjacent areas of the Pacific Ocean. Only nine RTUs were found on the Piip Volcano, among which there was one species, Provanna sp. nov., belonging to the family known only from chemosynthesis-based communities and another species, Parvaplustrim wareni , was potentially obligate for chemosynthesis-based communities. Nineteen RTUs have been identified in the methane seeps of the Koryak slope, however no taxa specific for chemosynthesis-based communities had been recorded. Gastropods have less aggregated population structure on the Koryak slope than on the Piip Volcano, where four times as many specimens have been collected. In general, the pattern of distribution of taxonomic and functional groups in the area of methane seeps of the Koryak slope is presumably the same as in the background communities while in the hydrothermal zone of the Piip Volcano it is similar to other types of extreme communities. Majority of gastropods from both regions feed on detritus or invertebrates. Most RTUs have a lecitothropic protoconch, which corresponds to a short period or absence of pelagic stage in their development. This makes the species associations of gastropods vulnerable. • 26 gastropod species are known from the reducing habitats of the Bering Sea. • Only two species are most likely obligate inhabitants of reducing biotopes. • Hydrothermal vents poorer than methane seeps in species richness but not in density. [ABSTRACT FROM AUTHOR]

With about 800 Recent species, 'miters' are a widely distributed group of tropical and subtropical gastropods that are most diverse in the Indo- West Pacific. They include the two families Mitridae and Costellariidae, similar in shell morphology and traditionally treated as close relatives. Some genera of deep-water Ptychatractidae and Volutomitridae are close to miters in shell morphology, and the term 'mitriform gastropods' has been introduced to refer to Mitridae, Costellariidae, and this assortment of convergent forms. The present study aimed at the reconstruction of phylogenetic relationships of mitriform gastropods based on representative taxon sampling. Four genetic markers [cytochrome c oxidase subunit I ( COI ), 16S and 12S rRNA mitochondrial genes, and H3 (Histone 3) nuclear gene] were sequenced for over 90 species in 20 genera, and the molecular data set was supplemented by studies of radula morphology. Our analysis recovered Mitridae as a monophyletic group, whereas the genus Mitra was found to be polyphyletic. Of 42 mitrid species included in the analysis, 37 formed a well-supported 'core Mitridae' consisting of four major clades, three of them consistent with the subfamilies Cylindromitrinae, Imbricariinae, and Mitrinae, and Strigatella paupercula standing out by itself. Basal to the 'core Mitridae' are four minor lineages, with the genus Charitodoron recognized as sister group to all other Mitridae. The deep-water family Pyramimitridae shows a sister relationship to the Mitridae, with high support for a Pyramimitridae + Mitridae clade. Our results recover the monophyly of the Costellariidae, which form a well-supported clade that also includes Ptychatractidae, Columbariinae, and Volutomitridae, but not Mitridae. Most derived and diverse amongst Costellariidae are species of Vexillum, characterized by a bow-shaped, multicuspidate rachidian tooth. Several previously unrecognized deep-water costellariid lineages are revealed. Their members retain some plesiomorphies - in particular a tricuspidate rachidian tooth - that makes them morphologically intermediate between ptychatractids and Vexillum. The taxa of Ptychatractidae included in the analysis are not monophyletic, but form three well-supported, unrelated groupings, corresponding respectively to Ceratoxancus + Latiromitra, Exilia, and Exiliodea. None of them shows an affinity to Pseudolividae. © 2015 The Linnean Society of London [ABSTRACT FROM AUTHOR]

Résumé Cet article présente les résultats de l’analyse d’assemblages malacologiques issus de deux couches du site paléolithique de Mezhyrich (Ukraine, Pléistocène supérieur). Un total de quatorze taxons de mollusques continentaux a été identifié. Ils sont répartis principalement dans les sept genres terrestres ( Succinella , Pupilla , Vertigo , Truncatellina , Columella , Vallonia , Chondrula ) et dans les 4 genres aquatiques ( Unio , Cyclas , Planorbis , Anisus ). On note en outre la présence de trois taxons de mollusques marins néogènes et d’un taxon de foraminifères, tous redéposés. Une courte caractérisation systématique des taxons de mollusques terrestres est présentée et illustrée. La malacofaune, prélevée dans des unités sous-jacentes aux couches archéologiques dites toptalishche , est typique de dépôts loessiques stadiaires, alors que celle associée aux toptalishche est caractéristique de conditions locales plus sèches et douces. This paper presents the results of the analysis of molluscan assemblages from two layers of the Paleolithic site of Mezhyrich (Ukraine, Upper Pleistocene). Fourteen terrestrial mollusc taxa were identified. They mostly belong to seven terrestrial genus ( Succinella , Pupilla , Vertigo , Truncatellina , Columella , Vallonia , Chondrula) and four aquatic ones ( Unio , Cyclas , Planorbis , Anisus ). In addition, we note the presence of three Neogene marine taxa and one foraminifera taxa, all redeposited. A short systematic description of the terrestrial mollusc taxa is presented with illustrations. The molluscan fauna sampled in units below the archaeological layers called toptalishche , is typical from stadial loessic deposits, whereas that associated with the toptalishche is characteristic of drier and milder local conditions. [ABSTRACT FROM AUTHOR]

The New South Wales (NSW) north coast has a diverse marine bivalve and gastropod fauna of biogeographical interest. A field survey at Shelly Beach, on the NSW lower north coast over the period 2009-2015, complemented by a review of data from secondary sources, identified 142 species comprising 34 bivalves (24 families) and 108 gastropods (51 families). It is likely that further survey effort, particularly targeting micro-molluscs less than 5 mm in size, would identify additional species. The molluscan fauna of Shelly Beach reflects the location of the NSW north coast in an overlap zone between the tropical Indo-West Pacific region to the north and the temperate southern Australian region to the south. Temperate zone species comprised about 63% of the identified species diversity, sub-tropical species about 20%, overlap zone endemics about 12% and widespread species about 5%.q [ABSTRACT FROM AUTHOR]

The biological and molecular knowledge of the marine life is of enormous importance in discovering new classes of natural products and in improving management and sustainable utilization of these useful genetic resources. Nonetheless, in this frame, genomic and organelle DNA isolation has been reported to be a limiting step, since downstream applications of molecular biology, such as restriction enzyme digestion, polymerase chain reaction (PCR) and DNA sequencing are hampered by the presence of compounds that are concurrently extracted. In this work we compared different DNA extraction techniques in three marine organisms and tested the downstream applications. One of the species utilized in this work was the Nudibranch Doris verrucosa L., a species with a well-known pharmaceutical interest. The phylogeny of this mollusc has long been discussed on the basis of morphological characters. As a result, D. verrucosa has often been misidentified with other sister species. Mitochondrial 16S rDNA sequence was chosen to better solve this concern and to accurately settle D. verrucosa into the right position. A partial sequence of the mt 16S rDNA of the Nudibranch D. verrucosa was obtained for the first time. The results here presented will provide knowledge useful to a better management and use of marine genetic resources, as well as in resolving taxonomic and identification issues currently open in these marine invertebrates. [ABSTRACT FROM AUTHOR]