ALBERT

Description: It is well known that land snails can be dispersed by birds, both by attachment to the body (ectozoochory) and by passing intact and alive through the bird's digestive tract (endozoochory). Endozoochory has, however, only been recorded for very small species. We examined the possibility that larger species (up to c . 17 mm in maximum shell dimension) could survive passage through a bird's digestive system. Live Alinda biplicata , Cochlodina laminata (both Clausiliidae) and Discus rotundatus (Discidae) were fed to 10 bird species (Corvidae, Turdidae, Sturnidae and Columbidae) in 14 experimental trials. Of 720 snails offered, 14 passed intact through the birds, of which nine were alive (eight clausiliids and one D. rotundatus ); thus more than 1% of all snails offered survived ingestion. In an additional experiment, some A. biplicata and C. laminata remained attached to birds' legs by pedal adhesion in simulated flight trials where the birds' legs oscillated at the maximum rate achieved during flight.

Description: Cephalopods show excellent camouflaged body patterning, but they also use body patterning for communication. It is not known whether body patterning responses can be shaped by learning. Here, we tested the hypothesis that cuttlefish ( Sepia officinalis ) can be conditioned to change their body pattern for a food reward. Cuttlefish were placed in a tank (all black or all white) and allowed to acclimate and settle into camouflaged body patterning (matching the tank colour). In each trial, a contrasting probe (white or black) was inserted into the tank. Experimental cuttlefish received a food reward if they broke camouflage (e.g. displayed light body patterning in the black tank or displayed dark body patterning in the white tank) within 15 s of the insertion of the probe; control cuttlefish received food rewards at random intervals. Experimental cuttlefish changed their body patterning more quickly and more consistently in response to the probe than did control cuttlefish, but only when they were trained in the black tank. We conclude that cuttlefish body patterning is not entirely innate, can be shaped by individual experience and appears to be more flexible than previous research has suggested.

Description: Snail shells represent an abundant source of information about the organisms that build them, which is particularly vital and relevant for species that are locally or globally extinct. Access to genetic information from snail shells can be valuable, yet previous protocols for extraction of DNA from empty shells have met with extremely low success rates, particularly from shells weathered from long-term exposure to environmental conditions. Here we present two simple protocols for the extraction and amplification of DNA from empty land snail shells from specimens of Galápagos endemic snails, including presumably extinct species. We processed 35 shells of the genus Naesiotus (Bulimulidae) from the Galápagos islands, some from species that have not been observed alive in the past 50 years. We amplified and sequenced short fragments (≤244 bp) of mitochondrial DNA (mtDNA) from 18 specimens. Our results indicate that the implementation of an ancient DNA extraction protocol and careful primer design to target short DNA fragments can result in successful recovery of mtDNA data from such specimens.

Description: The present study focuses on two apparent species: the giant thyasirid Conchocele bisecta (Conrad, 1849), which is the dominant species of the benthic community in a gas hydrate area with cold-water methane-rich vents at a depth of about 800 m on the slope off Paramushir Island (Kuril Islands, Sea of Okhotsk) and small unidentified thyasirid bivalves from this same community. An examination of the shell morphology of these thyasirids showed that the small bivalves were in fact young specimens of C. bisecta , characterized by a high individual and age variability. A transmission electron microscopic study of C. bisecta revealed gills with ‘Type 3’ filaments, which were extended abfrontally and had a distinct bacteriocyte zone with extracellular symbionts. The symbiotic bacteria found were spherical, similar to thiotrophic symbionts of other thyasirids. The isotopic 13 C values of C. bisecta soft tissues (from –39.6 to –33.8) were much heavier than those of methane in the Paramushir gas-hydrate area and matched the range characteristic of symbiotrophic bivalves harbouring sulphur-oxidizing chemoautotrophic bacteria. The variations in 13 C and 15 N recorded for large and small C. bisecta can be related to ontogenetic differences in life habit: small individuals are totally buried in the sediment, while large ones are half-buried. Data from fatty acid (FA) analysis indicate that sulphur-oxidizing symbionts constitute almost the entire nutrition of C. bisecta , with no significant contribution of symbiotic or free-living methanotrophs . Furthermore, neither FA nor isotopic compositions provided evidence for photosynthetic sources as food items for C. bisecta through filter feeding.

Description: The genus Liocarenus (Acteonidae) was originally described from Eocene fossil material and has subsequently come to include three subgenera ( Liocarenus s. s ., Bulimactaeon and Nucleopsis ) and nine species, including a Recent one ( L. globulinus ). Together, these have been accorded status as a subfamily, Liocareninae. We here present a taxonomic revision of all the species and subgenera historically ascribed to Liocarenus . We show that the genus name Liocarenus is an objective synonym of Hemiauricula . All three taxa ( Bulimactaeon , Hemiauricula and Nucleopsis ) are accepted at genus level and a new genus, Rapturella , is erected for the Recent species. Rapturella is diagnosed by a thick shell with rounded whorls, slightly stepped spire, two closely spaced subsutural spiral grooves, a weak columellar fold and a tooth-like palatal thickening. Three of the formerly included species of Liocarenus are here excluded from the Acteonidae. The revised classification is as follows: B. bernayi (Cossmann, 1892), H. edentula (Férussac, 1821), H. hilarionis (Bayan, 1870) n. comb., N. subvaricatus (Conrad, 1860), R. globulina (Forbes, 1844) n. comb. and R. ryani n. sp. (Acteonidae); Hamlinia eliai (Shalem, 1928) n. comb. and Globiconcha formosa (Cragin, 1893) n. comb. (Cylindrobullinidae); Ringicula lata (Conrad, 1865) n. comb. (Ringiculidae). Acteon costellatus Conrad, 1833 is considered a species inquirenda .

Description: Muricanthus fulvescens , one of the largest muricid gastropods in the world, was once thought to be a behavioural specialist, using its shell to grind feeding holes in bivalve prey. New experimental observations, however, reveal that this predator employs up to four modes of predation, including selective use of shell grinding and edge drilling in interactions with the large, thick-shelled venerid clam Mercenaria campechiensis . Shell-grinding attacks were found to be slightly faster than edge-drilling attacks, but had a lower success rate. Choice of predatory mode was more strongly correlated with the prey's anterior–posterior shell length than predator size. Smaller clams were attacked more frequently by shell grinding, while larger, thicker prey tended to be attacked by edge drilling. Several larger predators edge-drilled their prey successfully after first failing with the faster grinding behaviour; trial-and-error initiation of attacks with the more rapid grinding behaviour, however, was rare and expressed only by the largest predators. We also report an anecdotal observation of wall drilling and morphological evidence consistent with two modes of edge-drilling attacks, including drilling of larger holes for proboscis insertion and feeding and smaller, barely detectable (〈1 mm) holes for toxin injection. Toxin use is further supported by a lack of correlation between predator size and inner drill-hole dimensions. The occurrence of previously undetected diversity in predatory modes of M. fulvescens , a common, easily accessible species, demonstrates how much we have to learn about ecological versatility in muricids and its role in muricid evolution.

Description: The microanatomy of Ventsia tricarinata Warén & Bouchet, 1993 , a small coiled ‘skeneimorph’ gastropod from Pacific hydrothermal vents, is described based on computer-aided reconstructions of semithin section series and visualized by interactive 3D-modelling. This is the most complete account of the anatomy and histology of a seguenzioid vetigastropod presented to date, although details of the male genital system could not be detected. This species was placed originally in the Skeneidae (Trochoidea), but molecular data subsequently suggested a basal seguenzioidean position. The latter hypothesis is supported herein by morphological data, in particular by the conditions of the right neck (with two tentacles), the epipodium (with separated epipodial sense organs) and the bipartite seminal receptacle with concentric arrangement of sperm in its posterior part on the left side of the mantle roof.

Description: High levels of biodiversity and phylogeographic structure in marine species in Southeast Asia are strongly linked to Quaternary sea-level fluctuations and complex oceanographic conditions. Cellana toreuma is a common limpet on intertidal rocky shores and is widely distributed in the Western Pacific. Analyses of partial mitochondrial COI gene sequences from Southeast Asia, combined with previously published sequences from East Asia and Indonesia, revealed the existence of five well-supported clades with high genetic divergences (between 1.4 and 7.6%), namely the East Asia clade, the eastern Southeast Asia clade, the western Southeast Asia clade, the Pelabuan Ratu (Java) clade and the Ogasawara clade. The geographical distribution of the five clades is likely related to the history of glaciations and rapid postglacial population expansions. Analyses of pairwise ST and hierarchical analysis of molecular variance shows significant population structure among collections in East and Southeast Asia. These results suggest that historical events have had strong effects on the phylogeographic structure of C. toreuma . In addition, present environmental factors, such as unsuitable habitats and ocean currents, have also affected the genetic footprints of past environments.

Description: Information on the genetic population structure of endangered giant clams is important for conservation programmes and the understanding of ecological and evolutionary processes. In this study, the genetic population structures of three codistributed and ecologically similar giant clam species ( Tridacna crocea , T. maxima and T. squamosa ) are compared. A fragment of the cytochrome c oxidase I gene was sequenced as a genetic marker in three giant clam species sampled throughout the Indo-West Pacific, from the Western Indian Ocean (WIO) and Red Sea (RS) to the Eastern Indian Ocean (EIO), across the centre of marine biodiversity in the Indo-Malay Archipelago (IMA) to the Western Pacific (WP) and the Society Islands in the Central Pacific (CP). All three species showed limited gene flow and a highly significant genetic population structure. The st -values ( P 〈 0.001) are 0.46, 0.81 and 0.68 for T. crocea , T. maxima and T. squamosa , respectively. Based on a hierarchical AMOVA they could be divided into three to six groups from West to East: (1) WIO ( T. maxima and T. squamosa ), (2) RS ( T. maxima and T. squamosa ), (3) EIO (including Java Sea in T. maxima ), (4) central IMA, (5) WP and (6) CP ( T. maxima ). The distribution of the haplotype clades in the populations and the pairwise st -values between populations indicated a high level of gene flow in the central IMA for the three species. The concordant patterns suggest that geological history, sea-level changes during glacial periods of the Pliocene and Pleistocene, and oceanography are important factors shaping the genetic population structure of giant clams. The observed deep evolutionary lineages in the peripheral areas of the IMA might include cryptic species.

Description: Attaching objects to bivalve shells is an increasing requirement for conservation projects, mark-recapture studies and behavioural analysis. We investigated the suitability of eight different glues to attach a metallic object to a mussel shell and confirmed the utility of the best glue in a filtration behaviour experiment using Anodonta anatina . We used removal forces up to 1.35 kg cm –2 7 d after submerging in water and found an epoxy resin and a cyanoacrylate adhesive to perform best. Not all epoxy resins or cyanoacrylate adhesives performed equally. The best performing cyanoacrylate adhesive was used to glue magnets and rubber-coated Hall sensors to 26 mussels for a filtration-behaviour experiment. Nine months after attachment, all magnets and rubber-coated Hall sensors remained attached and withstood 1.35 kg cm –2 . The epoxy resin was not chosen, because it contained Bisphenol A and required a more complex application procedure. Mussel filtration behaviours were monitored for 96 h in the presence of algae. The results showed that the presence of algae stimulated the filtration rate of A. anatina in the first 24 h. Over the experimental period, the mussels' mean filtration duration was 20 ± 12 h, while the resting duration was 16 ± 7 h. We identified a pronounced circadian rhythm, despite the long filtration duration and variation in behaviour patterns. However, at any one time some mussels were observed to be filtering. The mussels were more likely to open their shells and become active at around 20:00. Thus the majority of mussels were active at midnight and a minority at noon. We interpret the strong response to increased algal concentration and the pronounced circadian rhythm as evidence that neither the glue nor the attached sensors disturbed the mussels even in a short-term experiment. Hence, we recommend the selected cyanoacrylate adhesive for use in tagging projects and behavioural studies of freshwater mussels.

Description: Reproductive mode, life cycle and fecundity are relevant to understand and predict the spread and impacts of invasive freshwater molluscs. Ampullariids or apple snails have been intensively studied in recent decades due to the fast global expansion and severe impacts of two species of Pomacea , a genus with a peculiar reproductive mode (aerial egg masses). We investigated the life cycle and fecundity of Asolene platae , an apple snail with a different reproductive mode (aquatic egg masses) from the Río de la Plata basin by following three cohorts from hatching to death under laboratory conditions. Growth of A. platae remained continuous during the 4-year lifespan and the snails reached 80% of their asymptotic size at an age of 1 year. In terms of the von Bertalanffy model, females attain higher asymptotic sizes (26.02–25.72 mm) than males (23.01–24.89 mm), but males grow to their asymptotic sizes at slightly higher rates than females (0.047–0.054 vs 0.050–0.057 week –1 ). Males matured at a smaller size (21.16 vs 24.53 mm) and much earlier (55.02 vs 84.88 weeks) than females. The survivorship curves showed 63% mortality during the first 2–8 weeks, almost no mortality for the following 2 years and finally a steady decline in the number of survivors, with at least 7% of the snails still alive after 3 years. The lifespan fecundity of females included 20.61 egg masses and 1429.9 eggs. The tertiary sex ratio of the three cohorts was balanced, but varied from 0.25 to 0.76 among egg masses. Our laboratory data indicated that, in temperate environments, A. platae males would mature in their second summer and females during their second or third summer, and that the survivors would reproduce again during the three following summers. Several attributes of the life cycle of A. platae (slow growth, high posthatching mortality, late maturation and relatively low fecundity) indicate lower invasive potential and population resilience than those of invasive apple snails.

Description: Four species of Pandora have been reported from southern South America: P. cistula Gould, 1850, P. braziliensis G. B. Sowerby II, 1874, P. diffissa Mabille & Rochebrune, 1889 and P. patagonica (Dall, 1915). The group has received little taxonomic attention in this area, resulting in arbitrary and wrong usage of these names, for which several contradictory synonymies have been proposed. This study provides the first revision of Pandora species living in southern South America, including photographs of the type material and descriptions of shells, gross anatomy and living animals. Out of the four species previously mentioned, P. braziliensis is here regarded as valid, including P. patagonica and P. diffissa as synonyms. The fourth species, P. cistula , remains known only from its type specimen. In addition, a new species, P. brevirostris , is described from the shallow waters of Argentina.

Description: Freshwater gastropods often contribute significantly to freshwater ecosystem biomass and are a vital component of many consumers' diets. They can also serve as a nutrient resource for terrestrial predators, representing an important example of nutrient transfer across a habitat boundary. This study uses bankside middens to provide evidence of predation by the brown rat Rattus norvegicus on the native freshwater gastropod Viviparus viviparus in a closed, lentic system in Ely, southeastern England. Conchological analysis of shell remains in middens compared with live snails in adjacent water sites suggested this predation could be size-selective for larger snails, and analysis of soft tissue dry weights and the mechanical force required to break shells suggested that this was driven predominantly by maximizing nutrient gain, rather than by optimizing handling effort. Aquatic gastropods represent a potentially important nutrient resource for brown rat populations; this resource may be used continuously through time or exhibit ‘resource pulse’ dynamics. Predation of this nature might also have important impacts on gastropod population structure, which may in turn impair ecosystem functioning.

Description: In this paper we attempt to clarify the identity of two purportedly new species of amnicolid snails in Pacific Northwest lakes that were vaguely described in grey literature and recently petitioned for federal listing. As currently understood the western American amnicolid fauna consists of the endemic genus Colligyrus (three species) and Amnicola limosa , which is distributed in a single site in western Montana (and also throughout much of eastern North America). The ‘Washington duskysnail’ was proposed for the Montana population of A. limosa and two recently discovered populations in northern Washington. The ‘masked duskysnail’ is a small amnicolid of uncertain generic status from two lakes in northern Washington. Our assessment of these putative species was based on genetic and morphological study of specimens from previously reported sites and recently discovered localities in Montana (both snails) and Washington (the first only). Molecular analyses (based on the mtCOI gene) resolved the western American populations of Amnicola as a weakly supported subunit of a clade that also contained eastern A. limosa and A. dalli ; the western Amnicola differed from eastern A. limosa and A. dalli by 2.1% mean sequence divergence. We also found that western Amnicola and eastern A. limosa do not differ in body pigmentation as previously postulated and that these snails are closely similar in all other morphological details. We conclude that the Washington duskysnail is not a distinct species and that all of the western populations of Amnicola are A. limosa . This finding extends the range of A. limosa westward almost to the Pacific margin. Our molecular phylogenetic analyses and study of the female reproductive anatomy of the masked duskysnail congruently indicated that this snail, which was previously compared with other western amnicolids, belongs to the genus Lyogyrus , which is otherwise restricted to eastern North America. We were unable to resolve the taxonomic status of the masked duskysnail further, owing to the paucity of pertinent data for the poorly known eastern Lyogyrus fauna. We recommend that the masked duskysnail be treated as ‘ Lyogyrus sp.’ pending further study of this genus.

Description: We document extensive incongruence between molecular phylogeny and the current taxonomy of the freshwater gastropod family Viviparidae in Japan. A phylogeny based on the mitochondrial cytochrome oxidase subunit I and 16S rRNA genes for East Asian viviparids comprises three major clades, the two largest of which are composed primarily of paraphyletic or highly polyphyletic taxonomic species. Sinotaia quadrata histrica includes several lineages whose geographical distribution and shell morphology are largely incongruent with their phylogenetic relationships. Several individuals identified as Heterogen longispira are nested within a clade of Cipangopaludina japonica . In contrast, Cipangopaludina chinensis laeta and C. c. chinensis from China are both monophyletic, but the two are not supported as sister taxa. The observed incongruence between phylogeny and taxonomy may be due to incomplete lineage sorting, introgressive hybridization and/or phenotypic plasticity. Further molecular phylogenetic analyses are needed to clarify the significance of the observed patterns and to verify the systematic relationships.

Description: Bellamya purificata is a widely distributed Chinese freshwater snail. It plays a significant role in ecosystem services. However, its natural habitats are under severe threat due to fragmentation and loss. In order to estimate the genetic diversity and population structure of B. purificata , 182 individuals from eight locations throughout its distribution across China were sampled. Seven microsatellite loci and the mitochondrial COI gene were genotyped. Our results showed that (1) the genetic diversity of B. purificata was high in all studied populations; (2) a low level of genetic differentiation existed among the eight populations with little restriction to gene flow; (3) no clear geographic structure was revealed by either Bayesian clustering, haplotype networks or AMOVA; (4) effective population size ( N e ) was moderate to high for all studied populations. The results of Bayesian Skyline plot analysis detected unstable population sizes through time for most populations. Passive dispersal during flooding events, zoochoric dispersal, possibly anthropogenic translocations and the large population sizes might be the major reasons for the lack of differentiation among Chinese B. purificata populations.

Description: Maritime transport, in particular of ballast water, is considered to be one of the most important pathways of marine biological invasions worldwide. Here we provide the first molecular evidence of potential survival of the European mudsnail, Peringia ulvae , in ballast water on cross-latitudinal voyages. Ballast water from the RV Polarstern was sampled at its departure from the North Sea and again in tropical latitudes; DNA was extracted and amplicon-sequenced employing high-throughput sequencing methodology. Mollusc species were detected by cytochrome oxidase subunit I DNA barcode sequences. The increasing proportion of operational taxonomic units that were identified as P. ulvae after 2 weeks of navigation suggests that this species withstands the harsh conditions in the ballast tank. As such, P. ulvae has the potential to reach very distant, new marine areas where it eventually might establish itself as a nonindigenous species. We also discuss the potential of environmental DNA analysis for en-route biodiversity screening and species-specific risk assessments, as well as some current limitations of the approach.

Description: We investigated the relationships of the muricid subfamilies Haustrinae, Pagodulinae and the genus Poirieria using a molecular phylogenetic approach on a dataset of three mitochondrial genes (12S, 16S and COI). These taxa form a well-supported clade within Muricidae. The phylogenetic analysis suggests that Poirieria is the sister group of Pagodulinae and that Axymene , Comptella , Pagodula , Paratrophon , Trophonella , Trophonopsis , Xymene , Xymenella , Xymenopsis and Zeatrophon are all worthy of genus-level rank within this subfamily. We propose the use of Enixotrophon for a group of species currently classified in Pagodula . The results also support a new taxonomic arrangement in Haustrinae.

Description: Mantellina translucens n. sp. inhabits the deep reefs (215–310 m) off southeastern Curaçao, occurring singly or in pairs, attached to vertical rock walls and boulders by thin byssal threads. This species differs from all living Limidae in having an exceptionally thin, comarginally corrugated shell that is longer than tall and lacks radial sculpture. This new species possesses a unique suite of characters associated with adaptations to an epibyssate mode of life in bathyal habitats, including simplification of the digestive tract, possibly indicating omnivory. It is assigned to the genus Mantellina Sacco, 1904, previously known only from fossil deposits of Burdigalian to Serravallian Miocene age of the Central Paratethys, on the basis of similar shell morphology. Anatomical characters and ribosomal DNA sequence data (18S and 16S genes) confirm placement of this taxon within the family Limidae, yet its shell superficially resembles those of several genera of the extinct family Inoceramidae, while differing in hinge morphology and shell ultrastructure. A preliminary molecular phylogeny recovered Limidae as a monophyletic clade within Pteriomorphia, with Mantellina derived relative to Limaria , and sister group to a clade containing the remaining representatives of Limidae. Ctenoides was not monophyletic. The phylogenetic tree based on molecular data does not support previously proposed suprageneric relationships based on morphological data.

Description: Ecological niche modelling (ENM) determines habitat suitability of species by relating records of occurrence to environmental variables. Here, we investigated habitat suitability of four terrestrial slugs of the genus Geomalacus from the Iberian Peninsula using ENM. The potential distribution of these species was estimated using maximum entropy modelling. For this we used published presence records, together with observations from our fieldwork, and 10 layers of environmental variables in a crossvalidation design using ‘minimum predicted area’ as a measure of success. For each species, the models predicted distributions with high accuracy, while restricting predictions to minimum areas. Precipitation, and to a lesser extent temperature, were the most important variables to predict the distributions of the four species. We then compared the predicted distributions with the currently known distributions. For G. anguiformis and G. maculosus the predicted distributions included the known distributions, but also nearby mountain areas where these species have not previously been found. For G. malagensis and G. oliveirae the models predicted much wider distributions. Subsequent dedicated fieldwork could not confirm the presence of G. oliveirae in the newly predicted areas. Conversely, G. malagensis was found at five new and distant localities, including areas in Portugal where the species has not previously been recorded.

Description: The Calopiidae Ponder, 1999 (Caenogastropoda: Truncatelloidea) are a family of aquatic microgastropods endemic to Australia. Of its four known species, three— Calopia minutissima , C. laseroni and C. imitata (all Ponder, 1999)—are broadly distributed, whereas C. burni Ponder, 1999 is restricted to southeastern Victoria. We used a concatenated dataset (1,261 positions), containing fragments of the mitochondrial genes COI and 16S, to generate the first molecular phylogeny of the family. Bayesian inference and maximum likelihood analyses of the combined dataset elucidate evolutionary relationships within the Calopiidae. Furthermore, C. imitata and C. burni were recovered as a strongly supported clade of negligible sequence divergence, so we view these two taxa as conspecific. Consequently, C. burni is synonymized herein with C. imitata , and a taxonomic reassessment of C. imitata is provided. A discriminant function analysis of shell dimensions suggests some morphological differences between populations of C. imitata , possibly expressing ecophenotypic variability.

Description: After its original description, the bivalve genus Malvinasia Cooper & Preston, 1910 was regarded as a junior synonym of Mysella or Rochefortia . However, due to the recent changes proposed in the classification and the concept of ‘mysellids’, the current status and concept of this genus remains unclear. In the present study, the relationships of the genus Malvinasia with Mysella , Rochefortia , Rochefortula and Altenaeum are reanalysed, based on the study of Malvinasia arthuri Cooper & Preston, 1910 , the type species of the genus. This species has a resilifer markedly introverted below the umbones and a right valve with a single, peg-like tooth, located anterior to the ligament. This peculiar hinge morphology is consistent throughout ontogeny in the genus, being present in at least four other South American morphospecies. Based on this evidence Malvinasia is considered a full genus, which is redescribed. In addition, Malvinasia piccola , a new species from the Atlantic coast of southern Patagonia is described and Mysella ( Rochefortia ) molinae Ramorino, 1968 is reallocated to Malvinasia . Information on the gross anatomy of this genus is provided by first time.

Description: Morphological uniformity in geographically widespread species may cause genetically distinct entities to pass unnoticed if they can only be detected by molecular approaches. The importance of uncovering such cryptic diversity is prompted by the need to understand the putative adaptive potential of populations along species ranges and to manage biodiversity conservation efforts. In this study, we aim to assess cryptic intraspecific genetic diversity and taxonomic status of the widely distributed intertidal mussel Mytilus galloprovincialis , along Atlantic southwestern (SW) Iberian, Atlantic northwestern (NW) Moroccan and Mediterranean Tunisian shores. By using mitochondrial (16S restriction-fragment length polymorphism) and nuclear (polyphenolic adhesive protein gene, Glu-5') markers, we discovered a more complex taxonomic diversity of M. galloprovincialis than previously known. Both Atlantic and Mediterranean haplogroups of M. galloprovincialis were detected along Atlantic SW Iberian shores along with M. galloprovincialis/edulis hybrids (92.2% Atlantic, 3.9% Mediterranean and 3.9% hybrids). In contrast, NW Moroccan populations consisted solely of Atlantic M. galloprovincialis . The Mediterranean populations did not include M. galloprovincialis/edulis hybrids, but both Atlantic (58%) and Mediterranean (42%) lineages were detected. Divergent selection between coastlines and/or indirect larval dispersal by human activities may be the drivers of this geographically structured genetic diversity.

Description: Autotomy of the foot is readily inducible in the predatory marine gastropod Agaronia propatula (Conrad, 1849), but the natural trigger of the autotomy response is obscure. Since cannibalistic predation has been observed in the species while interspecific predation on A. propatula has not, it was hypothesized that autotomy in A. propatula helps to defend against cannibalism. This hypothesis was tested in the present study. In our Costa Rican study population, autotomy as well as cannibalism occurred at significant rates; morphological indicators of foot regeneration suggested that 9–23% of the animals had autotomized previously, while about 5% of all observed predation attempts were directed at smaller conspecifics. However, autotomy in response to cannibalistic aggression was neither observed in the wild, nor did experimentally induced intraspecific aggression trigger autotomy. Successful cannibals generally were large and appeared to kill smaller conspecifics by suffocation in the metapodial pouch, but even then autotomy did not occur. These results refuted the hypothesis that A. propatula autotomizes to escape cannibalism. However, the size dependence of successful cannibalism on one hand, and the size spectrum of the population on the other, enabled a semiquantitative evaluation of the size-dependent intraspecific predation pressure in the population. The analysis indicated that in A. propatula different size classes represent ‘ecological species’ with distinct trophic roles. Since large A. propatula may actually reduce the total predation pressure on their heterospecific prey by cannibalizing smaller conspecifics, this size-dependent functional differentiation increases the complexity of the food-web around these snails.

Description: The biochemical composition and reproductive cycle of the pen shell Atrina japonica were investigated through separate analyses of the adductor muscle, gonad and the remaining tissues over a 1-year cycle. Seasonal variations in condition and gonadosomatic indices reflected those of gross weights of biochemical components of whole tissues. During the spring period, growth was initiated in the gonadal tissues simultaneously with the maximum weight gain in the adductor muscle, in which most of the energy reserves were stored, indicating that gametogenesis occurs at the expense of immediately ingested food energy. The increased energy reserves in the gonad during gametogenic development were exhausted completely during the summer spawning. Protein and carbohydrate reserves in the adductor muscle were used as catabolic substrates during spawning. The interannual shift in the timing of spawning appeared to be related to the changes in energy storage and gamete growth during the spring, probably reflecting changes in nutritional conditions in the ambient environment. Our results suggest that the adductor muscle of the pen shell plays a critical role as a major organ responsible for energy storage and that organ-specific biochemical composition can provide information of general relevance to the processes of energy gain and mobilization in bivalves.

Description: Hermaphroditic animals display a remarkable range of complex mating behaviours that are frequently related to the transfer of accessory-gland products. Here, we describe the use of the dart, an accessory reproductive device, and the mating behaviour of the hermaphroditic Cuban tree snail Polymita picta . Mating can be divided into three stages: courtship, copulation and post-copulation. Polymita picta has the longest mating duration of all Polymita species investigated so far. During courtship, a partial genital eversion exposes the sensitive zone, genital lobes and dart apparatus. During all mating stages, three uses of the dart apparatus can be distinguished: wiping, rubbing and stabbing, all of which mainly target the anterior region of the body, usually without loss of the dart. Morphological variation in the dart involves the extent of curvature, irregularities along the length and total length. These characteristics possibly provide a larger contact surface and deeper penetration through the body wall, which could result in increased sperm storage and paternity. The spermatophore is equipped with spines and we suggest that these might slow down spermatophore uptake into the bursa copulatrix. Overall, the general mating pattern, the presence of the sensitive zone, repeated use of the dart and its shape diversity support the idea that in more ancestral dart-possessing snails the dart apparatus is used to transfer accessory gland secretions, not only by stabbing but also through wiping and rubbing.

Description: Using the Pupilla faunas of Europe, North America, the Altai region of central Asia and eastern Asia, we consider whether the existing taxonomy based primarily on shell apertural characteristics correlates with relationships established on the basis of mitochondrial and nuclear DNA-sequence data. We obtained DNA sequence from nuclear ITS1 and ITS2 and mitochondrial COI and CytB from 80 specimens across 22 putative Pupilla taxa. The sequence data were analysed using maximum likelihood, maximum parsimony, Bayesian and neighbour-joining phylogenetic tree reconstruction, as well as base-pair substitution and insertion-deletion analysis. Revised species-level concepts were generated by identifying reciprocally monophyletic clades that exhibited unique conchological features. These analyses document that, although many previously described taxa have biological merit, the highly plastic nature of shell apertural features makes them unreliable indicators of species identity in several independent lineages. However, shell surface sculpture and architecture appear to provide more reliable diagnoses. Because of the traditional reliance of species-level taxonomy in Pupilla on plastic apertural features, too many species-level entities have been described in Europe and the Altai. Also, because taxonomically useful shell sculpture features have tended to be ignored, too few species have been described in eastern Asia and North America. As a result, confusion exists about species ranges, ecological tolerances and interpretation of Quaternary fossils within the genus. Based on these analyses three new species are described: P. alaskensis, P. hudsonianum and P. hokkaidoensis.

Description: We studied the bivalve Pinna nobilis in experimental conditions in order to measure its respiration rate (RR) and evaluate its adaptability to variable environments. We measured the RR of 30 fan mussels (34.0–64.9 cm shell length) and produced RR profiles at three different temperatures: estimated optimum living temperature of 20 °C and minimum and maximum conformability temperatures (16 and 25 °C respectively). The fan mussel is a high oxygen consumer and RR is reduced at the conformability limits of temperature in comparison to the estimated optimum living temperature ( T = 16 °C, 3.1 ± 1.2 mg O 2 h –1 ; T = 20 °C, 12.0 ± 3.9 mg O 2 h –1 ; T = 25 °C, 8.5 ± 3.8 mg O 2 h –1 ; n = 18 in each case). The data indicate that individuals were more stressed at 16 than at 25 °C. These observations will be of value for evaluating the potential distribution of P. nobilis , especially in shallow lagoons during summer when oxygen supply is potentially limiting.

Description: The land snail genus Rumina shows much intra- and interspecific variation in shell morphology. Three morphospecies are commonly recognized: R. decollata, R. saharica and R. paivae . The descriptions of these three morphospecies were based on differences in shell and genital characters for R. saharica and R. decollata, and shell size for R. paivae. However, recently DNA-sequence data have suggested that these morphospecies comprise at least seven phylogenetic species ( R. decollata molecular operational taxonomic units (MOTUs) A–F and R. saharica ). The present study explores to what extent these phylogenetic species are morphologically diagnosable and/or can be reconciled with the three currently recognized morphospecies. It shows that: (1) R. saharica , and to a lesser extent R. decollata MOTUs A and Eb, are significantly differentiated from the other phylogenetic species by both genital and shell characters, and can be regarded as three diagnosable biological and phylogenetic species; (2) there are no diagnostic genital features for R. paivae , so that this taxon should not be treated as a separate species; (3) none of the other DNA-based R. decollata MOTUs could be consistently differentiated by the shell and genital characters analysed in this study, so that their status needs further scrutiny.

Description: Temperature affects nearly all biological rates and consequently is fundamental to individual development time and timing of phenological events. One example is the duration of the pelagic larval stage of mussels, which is crucial for determining the magnitude and timing of recruitment, as well as population dispersal patterns. Understanding the impact of temperature on the rate of larval development is key to predicting the timing of settlement and optimizing mussel seed collection. Advising mussel farmers on Prince Edward Island about the ideal timing for collector deployment is one of the goals of the Mussel Monitoring Program (MMP). In this study we examine the relationship between the phenology of larval development based on MMP data, and satellite measurements of sea surface temperature. The analyses indicated that the first day of the year on which 10–20% of the pool of mussel larvae reached 250 µm could be predicted using the thermal integral measure growing degree-days. While this finding confirmed the importance of temperature for mussel larval phenology, the effect of other environmental variables such as phytoplankton quantity and quality cannot be dismissed.

Description: Ariunculus is a genus of terrestrial slugs often treated as a subgenus of Arion . A survey of the literature reveals doubts about many of the described species: only A. speziae and A. isselii are now generally recognized as belonging to Ariunculus. Ariunculus isselii is widespread on Sardinia. We describe its external appearance, mating behaviour and genital anatomy, and interpret the functioning of the genitalia based on specimens killed during copulation or shortly afterwards. Instead of the distinct epiphallus of Arion , there is only a small ampulla, because sperm are pumped out piecemeal to the recipient rather than transferred in a spermatophore. We speculate (in a framework of sexual selection theory) that this may explain why mating lasts 12 h after the initial genital eversion, much longer than in most Arion . The absence of a spermatophore provides grounds for keeping Ariunculus separate from Arion . Similarly to some Arion species, the papilla is inserted into the partner's partially everted bursa trunk; we discuss four different hypotheses for the function of this arrangement. Also as in some Arion species, the oviduct is everted during mating so as to apply a ligula. We provide information on egg laying in captivity and report that the species can self-fertilize.

Description: In the current context of environmental change, ocean acidification is predicted to affect the cellular processes, physiology and behaviour of all marine organisms, impacting survival, growth and reproduction. In relation to thermal tolerance limits, the effects of elevated p CO 2 could be expected to be more pronounced at the upper limits of the thermal tolerance window. Our study focused on Crepidula fornicata , an invasive gastropod which colonized shallow waters around European coasts during the 20th century. We investigated the effects of 10 weeks' exposure to current (380 µatm) and elevated (550, 750, 1,000 µatm) p CO 2 on this engineer species using an acute temperature increase (1 °C 12 h –1 ) as the test. Respiration rates were measured on both males (small individuals) and females (large individuals). Mortality increased suddenly from 34 °C, particularly in females. Respiration rate in C. fornicata increased linearly with temperature between 18 and 34 °C, but no differences were detected between the different p CO 2 conditions either in the regressions between respiration rate and temperature or in Q 10 values. In the same way, condition indices were similar in all the p CO 2 treatments at the end of the experiment, but decreased from the beginning of the experiment. This species was highly resistant to acute exposure to high temperature regardless of p CO 2 levels, even though food was limited during the experiment. Crepidula fornicata appears to have either developed resistance mechanisms or a strong phenotypic plasticity to deal with fluctuations of physicochemical parameters in its habitat. This suggests that invasive species may be more resistant to future environmental changes than its native competitors.

Description: The duration of drilling attacks on bivalve prey by muricid gastropods is largely a function of shell thickness at the drilling site selected by the predator. Attacks initiated at the thin valve edges (edge drilling) take significantly less time than drilling through the thicker shell wall (wall drilling). Here, we demonstrate experimentally that the muricid Chicoreus dilectus (Adams, 1885) employs the edge-drilling mode of attack nearly three times more often than wall drilling when exposed to chemical cues from the shell-crushing stone crab Menippe mercenaria , one of its natural enemies, than when foraging in isolation. Chicoreus dilectus is also known to edge drill more frequently in the presence of conspecific snails, which represent competitors for food as well as potential cannibals. Together, these findings suggest that edge drilling by C. dilectus should be considered as a general behavioural response to enemies instead of a specialized response to conspecific enemies. Although all snails exposed to stone crabs expressed the edge-drilling behaviour at least once, wall drilling was still more commonly used by each of these snails, suggesting that there are constraints on behavioural plasticity in the expression of edge drilling.

Description: Bivalves of the families Teredinidae and Xylophagaidae bore into and eat wood in shallow water and the deep sea, respectively. After an introduction to these sister taxa, I consider how they bore, focussing on the evolution of the cephalic hood in teredinids, which could contribute to the depth separation between the families. If the hood serves as a counter pressure to the foot, it may be vital in allowing teredinids to bore wood that contains air. The availability of wood has been suggested to determine the distribution of these animals. Mangrove habitats with abundant wood sustain the highest diversity, about one-third of all known teredinids. The open ocean, where wood is all but nonexistent, presents a nearly impassable barrier to most wood borers. Only after wooden sailing ships transported teredinids between ports did introduced species become problematic. Despite the rarity of wood in the open ocean, some xylophagaids live there as, it is hypothesized, do a limited number of teredinids; wood in the open ocean is predicted to be large because large size enhances buoyancy. The life history of open-ocean species may differ fundamentally from that of nearshore species. Physical stressors of temperature, salinity and desiccation appear to affect teredinids minimally; xylophagaids on the seafloor do not experience these variables. How biotic interactions such as competition and predation affect wood borers is yet to be thoroughly studied, but their impact may be greater than has been recognized, especially among teredinids. Although humans regard teredinids as pests that destroy wooden structures, and attempt to eradicate them from some areas, these animals play vital ecological roles. Teredinids make the energy and nutrients locked into wood available to the local community. Xylophagaids are nearly unique in breaking down cellulose and are analogous to primary producers in sustaining the diverse deep-sea wood-fall communities. The survival of borers requires wood to be present. The reduction of trees near water courses, removal of driftwood from navigable rivers and the destruction and fragmentation of the world's mangrove habitats all threaten the predictable supply of wood in the sea and may seriously threaten the survival of these molluscs.

Description: In 1990, Emberton hypothesized that the Madagascan land snail Helix covani Smith, 1879 was a previously unrecognized member of the Gondwanan family Rhytididae. The evidence put forward was based solely on features of the shell. The present paper sets out to explore this hypothesis in more detail, using morphological characters of the soft parts and molecular data, and so to test whether the present-day distribution of the Rhytididae includes Madagascar, a biogeographically interesting question. The results obtained from several independent suites of morphological characters are clearly inconsistent with the placement of Helix covani in the Rhytididae. Instead, the morphological evidence strongly supports its referral to the Acavidae, with affinity to the genus Ampelita , in which it has traditionally been classified. Molecular data are fully consistent with this, providing strong support for an acavid clade comprising Acavus , Ampelita , Helicophanta and Helix covani . Currently, the morphological and molecular data available are not sufficiently representative of Madagascan acavid diversity to permit further resolution of the affinities of the taxon in relation to Ampelita and Helicophanta .

Description: Karyological analysis of gill tissue from the marine gastropod Conus magus showed a diploid chromosome number of 32. Three major groups of chromosomes were identified: 22 median region, 4 submedian region and 6 subterminal region chromosomes. The haploid count was verified using chromosomal spreads from ovarian cells. Fluorescence in situ hybridization (FISH) physical mapping of an 18S rDNA sequence showed a wide distribution of major, medium and minor hybridization sites. These hybridization sites were detected in two to four different regions—paracentromeric, centromeric, interstitial or telomeric—per chromosome. Identical 18S rDNA FISH signals were found in the putative pairs of homologous chromosomes. FISH profiles of tandem simple-sequence repeats (SSRs) were physically mapped in locations near centromeres (GATA) n or telomeres (TTAGGG) n , as well as in noncentromeric (GATA) n regions and nontelomeric (TTAGGG) n interstitial regions of whole chromosome arms. Similar SSR chromosome organization FISH patterns were observed in two chromosomal spreads from the same individual: (1) telomeric (TTAGGG) n sequences in both p and q terminals of 15 chromosomes (10 median region, 2 submedian region and 3 subterminal region) and (2) centromeric (GATA) n sequences in 23 chromosomes (13 median region, 4 submedian region and 6 subterminal region). The C. magus DAPI karyotype and genomic landmarks based on the FISH profiles of 18S rDNA, (TTAGGG) n and (GATA) n sequences may contribute to the elucidation of the evolution of the karyotypes of Conus species and in the detection and localization of Conus chromosomal genes using FISH.

Description: The documentation of antipredator behaviour associated with different risk levels (threat-sensitive predator avoidance), different predators (predator-specific avoidance) or combined predators (multiple predator avoidance) in freshwater caenogastropods is limited. We studied the antipredator behaviour of predator-naive hatchlings of the invasive apple snail Pomacea canaliculata to chemical cues from the common carp ( Cyprinus carpio ), Reeve's turtle ( Mauremys reevesii ) and crushed conspecifics in three laboratory experiments. First, we tested the snails' responses of crawling out of the water and self-burial in the sand to odour from a single nonfeeding predator or crushed conspecifics. A greater proportion of snails responded to odour from crushed conspecifics than to turtle or carp odours. Second, we studied the snails' responses to cues simulating a single feeding predator. When combined with cues from crushed conspecifics, snails tended to bury themselves in the sand in response to the turtle odour whereas they tended to crawl above the waterline in response to the carp odour. Third, we compared the snails' responses to single or combined predator cues. In the presence of cues from crushed conspecifics, the snails' responses to the combined odours from turtle and carp were more similar to the responses associated with the carp odour than to those associated with the turtle odour. Overall, these experiments indicate that P. canaliculata hatchlings show fine-tuned innate antipredator behaviour.

Description: Life histories of the imperilled freshwater gastropod genus Leptoxis are poorly known, and this information is required to achieve a basic understanding of the evolution of this diverse group and to develop management strategies for species conservation and recovery. We describe egg-laying behaviours and associated traits for all 13 extant Leptoxis species. We also explore patterns of shell growth and assess the extent to which intraspecific shell variation is a result of phenotypic plasticity or genetic differences. Each Leptoxis species exhibits one of three distinct oviposition strategies: deposition of single eggs, deposition of eggs in a single line or deposition in circular clutches. Temperature cues for initiating egg laying varied from 12 to 26 °C depending on the species. There were significant differences in clutch size among species and between populations of L. ampla and L. taeniata . Furthermore, 1- and 2-year-old female L. foremani laid significantly fewer eggs per clutch than females 4 years or older. Finally, discrete shell morphologies that are characteristic of any given species are genetically controlled and not an ecophenotypic response. Clutch egg laying likely represents increased parental investment compared with other behaviours and clutches may provide individual eggs protection from predation or passive dislodgement. Data from this study, including necessary conditions for successful culturing and period of oviposition for each species, can inform captive propagation efforts for imperilled Leptoxis species and aid in predicting how they will respond to future habitat alteration and climate change.

Description: Accurate, phylogenetically informed taxonomy is required for any group of organisms to be used in biostratigraphy, palaeoecological and palaeoenvironmental studies, or palaeoclimatology. We use stratocladistic methods combined with morphometric data to produce a phylogeny of two closely related genera of New Zealand crassatellid bivalves— Spissatella Finlay, 1926 and Eucrassatella Iredale, 1924—and find that the inclusion of the stratigraphic character improves congruence of tree to data, as measured using retention indices. According to the resulting phylogeny, New Zealand taxa currently included in the genus Eucrassatella do not form a monophyletic group: ‘ Eucrassatella ’ australis (Hutton) occupies a basal position with regards to the rest of the taxa, and the remaining species of Eucrassatella , including the Australian type species E. kingicola (Lamarck), form a derived group that is sister to Spissatella . A full revision of the New Zealand species of Spissatella and Eucrassatella is presented, incorporating the results of this new phylogenetic analysis. Two species (‘ Spissatella ’ subobesa and the Australian ‘ S. ’ maudensis ) are transferred to the genus Eucrassatella ; the genus Spissatella is redescribed and the species assigned to it are reviewed. Spissatella maxwelli n. sp. is described and Triplicitella n. gen. is proposed for the oldest New Zealand species of crassatellid, ‘ Eucrassatella ’ australis .

Description: As a common sessile filter feeder with high bioconcentration rates, Dreissena polymorpha is useful as a bioindicator species. Pollution and environmental factors influence the reproductive effort of these bivalves. Therefore, the evaluation of the gametogenic cycle is important for understanding environmentally-related physiological alterations in this dioecious species. Animals from an unpolluted reference site close to the highly polluted Seine River, France, were monitored monthly over 1 year using qualitative and quantitative measures of gametogenesis. Developmental stages of the gonad were determined by visual inspection of histological slides. Unbiased quantitative stereological analysis was conducted to estimate oocyte development and the gonad index was determined. To investigate a possible role of female sex steroids in bivalve gametogenesis as a possible target for xenoestrogens, free oestradiol levels were assessed and analysed with respect to oocyte development. The basic pattern of the reproductive cycle consisted of early gametogenesis during autumn and winter, followed by rapid vitellogenesis in early spring, and spawning towards the summer months. However, the population was characterized by high inter-individual variability of the gonad stages. Furthermore, the simultaneous occurrence of different developmental stages within the same animal made classification difficult. Stereological determination of oocyte volumes as well as gonadosomatic index provided a more precise evaluation of reproductive effort. Oestradiol levels did vary significantly between months, but did not show any clear relationship with a particular stage of gametogenesis or oocyte volume.

Description: The systematic relationships of the Cerion uva complex and its constituent taxa are reviewed based on partial sequences of the cytochrome c oxidase I and 16S rDNA genes from 19 populations spanning the geographic range of the species complex and including the type localities of 8 of the 9 subspecies and forms. Molecular data support the conclusion of prior morphometric studies that all living Cerion inhabiting Aruba, Curaçao and Bonaire are members of a single species, C. uva . Sequence variability among and within populations is not sufficiently discontinuous to segregate populations into discrete, species-level taxa. Three of four subspecies, proposed on the basis of geographic isolation during the Quaternary, C. uva uva (Linnaeus, 1758), the nominotypical subspecies from eastern Curaçao, C. uva knipensis Baker, 1924, from western Curaçao, and C. uva bonairensis Baker, 1924, from Bonaire, are all supported by distinctive haplotypes. Cerion uva arubanum Baker, 1924, a taxon based on living specimens from Aruba, is shown to be a synonym of C. uva uva , with which it shares a preponderance of haplotypes. It is conjectured that C. uva was widespread on Aruba during the Quaternary, but had become extinct on that island, and was reintroduced from a population near Willemstad in eastern Curaçao by humans (either by Caquetío Indians or by European settlers) within the past 800 years. Further investigation is needed to determine if Quaternary Aruban Cerion warrant subspecific recognition. On the island of Curaçao, molecular data lend support to the partition of the Cerion fauna into C. uva knipensis , which is confined to an isolated western region, as defined by Baker, and C. uva uva , which inhabits a broad, eastern region that is composed of Baker's central and eastern regions. A population at Ronde Klip in eastern Curaçao has remained genetically isolated, and retains subspecific status as C. uva diablensis Baker, 1924. A neotype is designated for Turbo uva Linnaeus, 1758, as is necessary to provide an objective standard of reference for this species-group taxon, and for the genus- and family-level taxa based upon it.

Description: Animal species usually have a single sperm-storage site in the female body, but females of the squid Heterololigo bleekeri possess two distinct sperm-storage sites simultaneously. Use of two sperm-storage sites correlates with alternative male mating behaviours: large consorts guard females and place spermatophores inside the oviduct just before spawning, whereas small ‘sneaker’ males place spermatophores on the membrane around the female's mouth within the arm crown, where a seminal receptacle is present. Previous work showed that spermatophore and sperm morphology diverge between consort and sneaker males. Here we show novel dichotomous adaptations in the sperm-transfer strategy of males of this squid, associated with the use of two distinct sperm-storage sites on females. The spermatangia ejaculated from spermatophores were clearly dimorphic: all spermatangia ejaculated from spermatophores smaller than 12 mm from small sneaker males were drop-shaped, whereas all spermatangia from spermatophores longer than 12 mm from larger consort males were rope-shaped. In addition, the drop-shaped spermatangia were distinct in having a spine on their base, which might reduce the risk of it being shed from the female's body surface. Our findings suggest that existence of alternative sperm-storage sites, and related biological and environmental factors, lead to the evolution of divergent sperm-transfer strategies.

Description: Prescribed burning is commonly used for vegetation management. Whereas effects on vegetation are apparent, effects of these burns on ground-dwelling invertebrates are not. Land snails are especially susceptible to burns. Snail loss occurs directly from burns, but may also occur post-burn because of altered habitat conditions, although post-burn loss has not previously been tested. We used a field experiment to investigate snail survival and factors affecting survival in post-burn habitats. We exposed snails (Discidae: Anguispira alternata ) to combinations of intact leaf litter, wood shelters, burned leaf litter, charred wood and ash added to leaf litter, to simulate a variety of post-burn conditions. Half of the replicates were watered every 3 d, which allowed detection of desiccation effects in comparison to ambient water conditions. The on-going drought resulted in high snail mortality. Watering increased survival and, as a consequence, growth. Snail mortality was higher in habitats with burned leaves and/or wood than in unburned habitats. Higher temperatures and rapid initial mortality in burned habitats, and increased survival with watering, indicated that the major cause of post-fire mortality was desiccation, rather than starvation. Contrary to expectations, snails in burned-leaf habitats grew more than snails in unburned habitats, and this greater growth was associated with higher soil pH. Snails surviving fires in burned woodland areas likely have high post-burn mortality. Our experiment highlights the negative impacts of burned woodland habitats on some nontarget organisms and indicates that prescribed burns should be avoided during exceptionally dry conditions.

Description: Patella ferruginea is considered to be the most endangered marine invertebrate of western Mediterranean rocky shores. Its critical risk of extinction calls for the need to monitor the remaining populations and evaluate the status of the species at a local level. We have initiated a long-term demographic monitoring programme of the P. ferruginea population in Ceuta (North Africa, Strait of Gibraltar), one of the most important remaining populations in terms of size and density of individuals. Here we provide the longest demographic information available for this species. Seven sites were selected, with different degrees of accessibility. At each site, three 10-m transects were delimited and all the P. ferruginea individuals were counted and measured yearly. During the first 5 years of the monitoring programme (2007–2011), we recorded a 61.9% increase in the overall number of individuals. Site accessibility (positively correlated with the impact caused by human collection) is a good predictor of P. ferruginea population structure and density; while subpopulations located in easily accessible sites showed an increase of 8.7% in the number of adults (〉25 mm), other subpopulations with more difficult access increased by 80–100% in the 5-year interval. Results also provided new insights regarding recruitment processes in the species, suggesting that the number of adults located within the immediate vicinity influences larval settlement. We conclude that legal measures such as the creation of artificial marine micro-reserves should be considered in order to develop a network of small reserves that may help the viability of this species.

Description: Exotic invasive plants are known to decrease mollusc species richness and also abundances of many snail species. However, there is not much evidence on how invasive plants influence snail trophic behaviour. In this study, food preferences of alluvial land snails for invasive plants were studied. Two snail species ( Succinea putris and Urticicola umbrosus ) that commonly climb up invasive plants were chosen for food preference experiments. The five most widespread exotic plant species invading river floodplains in Central Europe ( Impatiens glandulifera, Helianthus tuberosus, Fallopia japonica, F. sachalinensis and F. x bohemica ) and one native species ( Urtica dioica ) were chosen as food for the snails. Results of the study confirmed a broadly accepted opinion, that land snails prefer senescent to fresh plant material. The climbing efforts of the alluvial snails is therefore not for the purpose of foraging. The most important factors for snail food preferences were plant species identity and leaf condition. The exotic plants were consumed to different extent, probably due to differences in defence mechanisms. The highest consumption was recorded for H. tuberosus and U. dioica , which are protected on their surface by trichomes. Plants of the genus Fallopia , containing various secondary metabolites and high content of lignin, were mostly rejected. The native food source U. dioica did not change the preferences of the land snails when offered together with the invasive plants.

Description: We investigated whether individuals of the intertidal snail Littorina littorea may be attracted by water-borne and air-borne pheromones from conspecifics. The potential relative role of water-borne and air-borne pheromone in the behavioural and reproductive biology of L. littorea was assessed through chemotactic assays. These involved a series of choice experiments with snails, snail smell and snail mucus as stimuli in a T-maze under conditions of immersion and emersion, and during the nonmating and mating seasons. During the nonmating season, L. littorea did not choose the snail-conditioned side of the T-maze significantly more frequently than the control side under conditions of both immersion and emersion. During the mating season, under condition of immersion both males and females chose the side of the T-maze conditioned with individual of the opposite sex significantly more frequently than the control side, and did not show any preference for the side conditioned with individuals of the same sex. Under conditions of emersion, only males were significantly more attracted by cues from the opposite sex than by the control. These results indicate that L. littorea are not attracted by conspecifics during the nonmating season; the cues of conspecifics are then unlikely to play a role in the orientation or the aggregation behaviour of this species. The results also suggest that males and females are attracted by the odour of conspecifics of the opposite sex, which contains both water-borne and air-borne pheromones in females and only water-borne pheromones in males. Also the similar behaviours observed with snails, water-borne and air-borne snail smell, and snail mucus, as stimuli indicate that male and female sex pheromones are both present in mucus. Temperature manipulations conducted during both seasons did not affect any of the observed behavioural changes, hence suggesting that the chemoreceptive abilities of L. littorea may be driven by exogenous and/or endogenous factors that are decoupled from direct control by temperature. This is in sharp contrast to the locomotor activity of L. littorea , which consistently increased with temperature. We also report the possibility of mate-tracking in females, a behaviour that has yet to be reported in gastropods, since males are typically believed to be the active sex that searches for females. Our results build on previous evidence of the function played by mucus-trail following in the reproductive success of intertidal gastropods, through the ability of L. littorea to remotely detect the water-borne and air-borne sex-specific cues that are incorporated in their mucus.

Description: Unio ravoisieri is an endemic freshwater mussel inhabiting North Africa rivers. Morphological diversity in U. ravoisieri was examined at eight sites covering the three main drainage systems in northern Tunisia. Variation was assessed using 10 shell measurements in 193 specimens. Univariate and multivariate analyses were applied to test the effects of sex and sites on shell traits. Simple and partial Mantel correlations on external and internal shell traits and geographic locations of populations were performed to test for spatial effects. Our results showed significant differences in shell morphometric characters among locations, but no evidence of sexual size dimorphism. Mantel correlations between geographic and all shell morphometric distances were significant, indicating an isolation-by-distance pattern. However, partial Mantel correlation did not detect a significant correlation between internal and external shell morphometric distances after controlling for geographic distance. The nonparametric Spearman correlations between geographical parameters (latitude, longitude and altitude) and external shell traits, as well as growth index were significant, but no significant relationships were demonstrated for internal traits or for condition index. Assessment of the underlying processes involved in this differentiation is not straightforward, because of the likely complex interaction between genetic and environmental factors.

Description: The Neptune whelk, Neptunea arthritica , is a sublittoral snail from Pacific waters that is a food resource and supports a commercially important fishery in northern Japan. This species showed a severe decline during the 1970s and 1980s, possibly because of overfishing, imposex caused by tributyltin (TBT) pollution and parasite infection. In the present study, we investigated genetic variation among the populations of N. arthritica from eight localities in northern Japan, including Hokkaido and Aomori, using a mitochondrial DNA (mtDNA) marker, a partial sequence of the cytochrome c oxidase subunit I (COI) gene. We also addressed the evolutionary history of N. arthritica and human impact on the population genetic profiles of this species. The parsimony network showed 14 COI haplotypes separated into two groups (Groups A and B), with an intermediate haplotype connecting both groups. Among eight populations, six were fixed for only one or two haplotypes, and no geographic-genetic correlation was found; they were probably affected by random drift. These results contrasted with those from previous microsatellite analysis, which indicated that geographic structure was the result of restricted gene flow between populations. Our results suggested that N. arthritica diverged into Groups A and B during the Pliocene; however, recent TBT pollution and size-selective fishing pressure have reduced genetic diversity and concealed the natural population structure. The present study also suggested that human impact may cause longstanding and possibly irreversible modification of ecosystems, particularly for species forming discrete and relatively small local populations, such as N. arthritica . Thus, the combined use of mtDNA and microsatellite genetic data provides a powerful tool to investigate the health of biodiversity in molluscs.

Description: We present a new classification for the genus Conus sensu lato (family Conidae), based on molecular phylogenetic analyses of 329 species. This classification departs from both the traditional classification in only one genus and from a recently proposed shell- and radula-based classification scheme that separates members of this group into five families and 115 genera. Roughly 140 genus-group names are available for Recent cone snails. We propose to place all cone snails within a single family (Conidae) containing four genera— Conus , Conasprella , Profundiconus and Californiconus (with Conus alone encompassing about 85% of known species)—based on the clear separation of cone snails into four distinct and well-supported groups/lineages in molecular phylogenetic analyses. Within Conus and Conasprella , we recognize 57 and 11 subgenera, respectively, that represent well-supported subgroupings within these genera, which we interpret as evidence of intrageneric distinctiveness. We allocate the 803 Recent species of Conidae listed as valid in the World Register of Marine Species into these four genera and 71 subgenera, with an estimate of the confidence for placement of species in these taxonomic categories based on whether molecular or radula and/or shell data were used in these determinations. Our proposed classification effectively departs from previous schemes by (1) limiting the number of accepted genera, (2) retaining the majority of species within the genus Conus and (3) assigning members of these genera to species groups/subgenera to enable the effective communication of these groups, all of which we hope will encourage acceptance of this scheme.

Description: Seasonal differences in the water content of four Codringtonia species were investigated using specimens collected from the field. In addition, rate of water loss and expression of heat-shock protein 70 (Hsp70) were measured in a laboratory setting with six Codringtonia species subjected to a short-term heat shock. Using a phylogenetic framework, both the Hsp70 expression levels and the rate of water loss were investigated for their correlation with spatial and climatic variables. As indicated by the field-collected samples, during summer aestivation only C. helenae exhibited a tendency for water loss. During the short-term heat shock the rate of water loss in C. helenae was also significantly greater. No interspecific differences could be detected in the levels of Hsp70 in the species subjected to short-term heat shock. A single Codringtonia species seemed to maintain increased Hsp70 protein levels. In the species subjected to short-term heat shock, a positive relationship was found between Hsp70 levels and rate of water loss. On the other hand, the Hsp70 levels under normal conditions showed a negative correlation with altitude and mean summer precipitation of the sampling localities. Thus, species seem to adapt to harsher environmental conditions by maintaining higher levels of Hsp70.

Description: The objective was to evaluate the modulation of gene expression of insulin-like receptor (a receptor with a fundamental role in insulin-signalling pathway) in response to feeding in the bivalve Mesodesma donacium . A partial sequence of insulin-like receptor gene ( MdIR ) was identified and evaluated in five tissues: mantle, foot, gonad, digestive gland and gill, by qPCR analysis. MdIR expression was evaluated in two experimental groups either constantly fed with Isochrysis galbana or starved for 20 d. The molecular characterization of MdIR revealed a partial sequence of 767 bp and two conserved catalytic sites. The qPCR analysis showed higher levels of expression in the digestive gland over other tissues. Additionally, the clams constantly fed with microalgae showed higher transcripts levels of MdIR than those subjected to starvation. The results support the hypothesis that the insulin-like receptor is activated in response to feeding activities and associated metabolism in M. donacium , which could be used for evaluating growing and reproduction conditions in bivalves.

Description: The littorinid gastropod Littoraria flammea has been widely quoted as one of only three or four marine molluscs believed to have become extinct in historic times. It is easily recognized by its delicate, elongate, striped shell. We review the literature and available museum material to show that its only recorded locality was Shanghai and that it has not been collected since about 1855. We report the rediscovery of this species in salt marshes near Shanghai, where the habitat is under threat from invasive Spartina . For the first time we describe the penis, pallial oviduct and radula. These are the same as those of L. melanostoma , previously recorded only from Fujian province and southwards, where its shell is different from that of L. flammea . We now report a population of L. aff . melanostoma from between Fujian and Shanghai, with shells of intermediate form and colour. Analyses of sequences of COI, 12S and 28S genes do not support separation of these two Littoraria species, in terms of either reciprocal monophyly or genetic distance. Present evidence suggests that L. flammea could be only a distinctive morphological form or extreme of a cline, at the northern limit of the range of L. melanostoma .

Description: The organogenesis, histogenesis and growth of larvae of the fighting conch Strombus pugilis (Linné, 1758) were studied over a period of 30 d after hatching in laboratory culture. Early development of S. pugilis was examined by light and scanning electron microscopy. Rearing was conducted at 27 ± 1 °C. Veligers were reared at 200 larvae l –1 in 4-l containers. Larvae were fed with the microalgae Isochrysis galbana and Nanochloropsis oculata at a concentration of 1,000 cell l –1 . The protoconch at hatching measured 212 ± 12.14 μm in length and the shell reached 1,100 ± 29.11 μm 29 d after hatching. Development characteristics are described from hatching to settlement. Newly hatched veligers possess two velar lobes, a larval shell consisting of 1.5 whorls, eyespots and a single right tentacle. Late veligers (5-d old larvae) have four velar lobes and two shell whorls and the left tentacle appears. Pediveligers show a functional adult heart at 11 d. Crawling behaviour and settlement were observed from 27 to 31 d. Plantigrades were observed after 29 d, when a functioning proboscis is observed and the velar lobes are lost. This study will facilitate the identification of gastropod larval shells in the plankton and of juveniles in the meiobenthos and will aid aquaculture of Strombus species.

Description: Paphies ventricosa is a large (up to 150 mm shell length) surf clam endemic to New Zealand, with a geographically patchy distribution. Using scanning electron microscopy and light microscopy, its fertilization, embryonic and larval development were observed at three culturing temperatures (12, 16 and 20 °C). The progress of development follows that previously described for the family Mesodesmatidae, with P. ventricosa having a small egg (63–70 µm), with a 83–102 µm trochophore stage observed at 15 h, and a 100 µm D-veliger larva observed at 22 h at 12 and 16°C, and 37 h at 20 °C. At 20 °C, the pediveliger larval stage was reached by 31 d. While the morphology of the embryonic and larval stages of P. ventricosa is typical for bivalves, we show that in this species the shell field invagination occurs in the gastrula stage and that the expansion of the dorsal shell field occurs during gastrulation, with the early trochophore having a well-developed shell field that has a clearly defined axial line between the two shell lobes. The growth of P. ventricosa larvae cultured at 12, 16 or 20 °C over 39, 33 and 31 d respectively, was faster at warmer temperatures. Using the temperature quotient Q 10 at day 27 to quantify the response to temperature, values of Q 10 = 1.82 for the range 12–16 °C and Q 10 = 2.33 for the range 16–20 °C were calculated. Larval shape was not temperature dependent, suggesting that the smaller larvae found at colder temperatures reflect a slowing of larval development, rather than physiological damage by temperature resulting in abnormal larval development.

Description: The anatomy and development of the tails at the posterior part of the mantle were studied in several groups of Recent and extinct coleoid cephalopods; substantial differences in their formation were revealed. Males of the Recent loliginid squid Alloteuthis spp. form their tail by increased growth of the anterior part of the gladius with simultaneous growth of the posterior mantle. As a result, the gladius rolls longitudinally in the tail forming a pseudoconus. The attenuated tail in males of the squid Lycoteuthis springeri (Lycoteuthidae) is supported from inside by the special rod-like apical vacuolated cartilage. Adults of both sexes of recent Onykia robsoni and O. robusta form a carrot-shaped flexible chitinous rostrum supporting the attenuated tail. Adults of several Jurassic belemnites formed an elongated epirostrum posterior to their orthorostrum; the structures differed in growth and microstructure. Counts of growth microincrements within the orthorostrum and epirostrum were used to date their formation and estimate the age of belemnites. The development of the long rigid tail and the corresponding shift of the fin to the middle part of the mantle streamline the body and possibly facilitate the animal's movement in the water by gliding. The analogous tail formation in several independent groups points to its adaptive nature for the development of a more mobile adult phase in species of coleoid cephalopods.

Description: A new genus and species of a deep-sea dorid nudibranch is described. Elfdaliana profundimontana n. gen, n. sp. is the first taxon of the family Polyceridae with a gill cavity. The new genus possesses diagnostic characters of other polycerids, including globular structures on the branched lateral processes, a radula with broad rachis and differentiated outer lateral teeth. This discovery agrees with recently proposed phylogenetic frameworks and supports a development-based model for the evolution of the dorid nudibranchs, placing the cryptobranch condition as ancestral. A synopsis of the ontogenetic stages representing major dorid cryptobranch and phanerobranch lineages (including novel data on three species) is presented for the first time. Phylotypic periods for the dorid nudibranchs are indicated. It is suggested that the phenomenon of conserved phylotypic periods makes it possible to apply a Periodic Table-like approach to biological taxonomy and phylogenetics.

Description: A morphological study revealed that the NW American soft-bottom bivalve Nutricola tantilla is dioecious, not a protandric hermaphrodite as previously reported. We base this conclusion on the smaller males having highly specialized, glandular sperm ducts, while the larger females have simple oviducts and no transition between the two ducts occurs. The females are brooders and retain their ova in a marsupium within the dorsal part of the inner demibranchs. Sperm cells were present and associated with a mesh-like tissue among the ova or early-stage embryos. How this tissue originates is still unknown. We suggest that sperm cells dissociate from this pool and fertilize the oocytes as soon as they are ovulated. The mode of sperm storage in N. tantilla represents a unique case in that the sperm are presumably nurtured within a nonepithelial tissue. We describe the ultrastructure of the sperm cells in N. tantilla. Large, spherical cytophores become associated with a multitude of acrosomes of spermatozoa and probably represent the precursors of the spermatozeugmata that have been described previously.

Description: The ‘scaly-foot gastropod’ is widely recognized as an iconic species of deep-sea hydrothermal vent ecosystems in the Indian Ocean. Uniquely among gastropods, this species carries hundreds of dermal sclerites on its foot and these scales can be covered in iron sulphide that also covers its shell, making it the only extant metazoan known to utilize iron sulphide as part of its skeleton. It has not been formally named, despite attracting great attention from both scientists and the general public alike, although a manuscript name has occasionally been used in various sources. The RRS James Cook JC67 expedition in 2011 sampled the biota of the Longqi vent field (37°47.027'S, 49°38.963'E), Southwest Indian Ridge, for the first time, revealing a previously unknown population of the ‘scaly-foot gastropod’. The present study gives a formal name to the ‘scaly-foot gastropod’, Chrysomallon squamiferum n. gen., n. sp. with Longqi vent field as the type locality. The erection of the new monotypic genus is supported by both morphological and molecular characterization, differentiating it from existing genera of the family Peltospiridae. Analysis of the cytochrome c oxidase subunit I gene reveals a 24–26% pairwise distance between Chrysomallon and five other genera of Peltospiridae, while the range among those five genera is 14–25%. The new genus is placed in the family Peltospiridae based on morphological characteristics, including lack of sexual dimorphism, no copulatory organ, the distal end of marginal teeth being subdivided into many denticles and the ventral margin of the gill leaflets carrying a series of bulges. A five-gene Bayesian phylogenetic reconstruction does not contradict the placement within Peltospiridae.

Description: The rock-dwelling land snail Pyramidula pusilla was analysed genetically and morphologically with an emphasis on its eastern Alpine distributional area. Genetic variation and phylogeographic patterns were inferred by mitochondrial cytochrome c oxidase subunit 1 gene sequences (650 bp), while shell variability was investigated by shell measurements and landmark analyses. The phylogenetic analyses revealed two clades in Austria (clades 3 and 4), of which one also contained individuals from Turkey. Other samples originating from the Balkan region (Albania, Greece) and Turkey were well separated in the tree, forming two distinct sister clades (clades 1 and 2). Concerning clades 3 and 4 there is no clear geographical pattern and both clades cooccur at several (11) sites; the same is true for clades 1 and 2. There are also morphological differences between clades: clades 1 and 2 differ from the other clades in size as well as shape, whereas clade 3 differs from clade 4 only in size. Considering all results combined, they imply that the samples analysed might actually represent more than one species and that, contrary to former assumptions, two species of Pyramidula may occur within the eastern Alps. However, comprehensive taxonomic conclusions cannot yet be drawn, for reasons connected with insufficiently justified species assignment: (1) high morphological variation within clades, (2) lack of clear diagnostic information in original descriptions, causing a lack of reliable distributional data and (3) lack of data over the whole distributional range of the genus. Analyses of ncDNA (e.g. microsatellites) to quantify the extent of gene flow, as well as breeding experiments between different clades, could help to clarify the delimitation of species. Despite these taxonomic uncertainties, the results provide insights on Pyramidula within the eastern Alpine region, suggesting that it survived the Pleistocene oscillations without dramatic bottlenecks and is capable of fast expansion to (re)populate formerly glaciated areas.

Description: Restriction-associated DNA sequencing methods are useful for simultaneously developing and genotyping DNA markers such as single nucleotide polymorphisms (SNPs). We describe a new inexpensive protocol for double-digest restriction-associated DNA (ddRAD) sequencing, requiring purchase of only two double-stranded adapter oligonucleotides complementary to the overhanging bases left by digestion with chosen restriction enzymes. Indexing of samples is instead achieved by incorporating two unique index sequences into the forward and reverse primer sequences, so that they can both be added with PCR. This modification enables combinatorial indexing of samples by paired-end sequencing. We tested this method by preparing individual genomic libraries from two putative parents and eight putative offspring from an experimental cross of a marine snail ( Littorina saxatilis ); each snail's DNA was extracted, double-digested with PstI and BglII , then ligated to adapters. More than 90% of the reads (12,175,413 paired-end reads and 24,350,826 total sequences) could be assigned to the sequenced individuals. Trimmed, paired reads from the putative parents were assembled into 3,421 contigs with an N50 of 135 bp. Reads from all individuals were aligned to the parental reference assembly, allowing discovery and validation of 1,131 variant SNP sites genotyped in all individuals, with mean coverage depth of 33.54 reads per locus. Individual genotypes at each of 1,131 loci were used in parentage analysis in COLONY 2.0.4.4 and confirmed that the putative parents were the true parents of eight sequenced offspring. This study demonstrates the utility of the new low-cost ddRAD protocol for library preparation and SNP variant discovery, and will enable flexibility in choice of restriction enzyme and decrease in startup costs of future ddRAD studies in molluscan species.

Description: The Indo-Pacific genus Spiniphiline Gosliner, 1988 was erected for a rare species of Cephalaspidea characterized by an internal shell with spines. Spiniphiline kensleyi Gosliner, 1988 was until now the only known species. During the ‘Karubenthos’ expedition to the archipelago of Guadeloupe (Lesser Antilles, Caribbean Sea) coordinated by the Muséum national d'Histoire naturelle, Paris, a small philinid was captured on a mäerl bed. This specimen is here described as a new species of Spiniphiline — S. persei . Its occurrence in Guadeloupe is the first record of the genus in the Atlantic Ocean. The systematic position of Spiniphiline is discussed and evidence given for its inclusion in the family Philinidae s. s.

Description: Species are fundamental units in evolutionary biology. However, defining them in taxonomically problematic groups requires integration of independent sources of information in order to develop robust hypotheses for taxonomic classification. Here, we propose an integrative framework for species delimitation in the Mediterranean species of the genus Cerithium (Caenogastropoda: Cerithiidae), whose shells show a wide variety of forms resulting in problematic morphological identification at the species level. Combined sequence data of two mitochondrial genes (COI+12S) for 55 individuals from the central Mediterranean Sea were used to test the species status of six identified morphotypes. Phylogenetic analyses, as well as DNA-based methods of species delimitation (automatic barcode gap discovery, species delimitation plugin and genealogical sorting index), support the species status of three morphotypes ( C. vulgatum = MOTU-A, C. alucastrum = MOTU-B and C. protractum = MOTU-C), sometimes considered as ecotypes. Molecular operational taxonomic unit (MOTU)-D includes large individuals morphologically assigned to C. vulgatum (from Brindisi and Oristano) and C. repandum (from Tunisia), but all probably represent C. repandum which, if valid, would then not be endemic to its type locality in the Gulf of Gabès. All individuals identified as C. lividulum grouped in MOTU-E, except those from Tunisia which cluster in MOTU-F with some C. renovatum. Cerithium renovatum from Crete forms an endemic group (MOTU-G), suggesting a possible cryptic species. Our results show only partial concordance between traditional morphology and sequence data, indicating that the former is not always sufficient for recognizing species level taxa within Mediterranean Cerithium , although protoconch morphology is a key feature for distinguishing between species with superficially similar teleoconchs. Further analyses based on more comprehensive geographic sampling and more mitochondrial markers, and including a number of nuclear loci, are needed to clarify Mediterranean Cerithium diversity more fully.

Description: The aims of the study were to infer phylogeographic relationships between the populations of the minute, dioecious, spring-inhabiting snail Grossuana from the Balkans, and to interpret the resulting pattern in the context of geological history of the region. The cytochrome c oxidase subunit I gene was sequenced from 23 previously unstudied populations of Grossuana from Bulgaria and analysed together with published sequences from the other populations of Grossuana from the Balkans. In Bulgaria, six clades or putative clades (lacking statistical support) were identified. Within the clades the p-distances were in the range 0.2–0.9% and between the clades 1.6–3.4%. Among all 33 studied populations, 42 haplotypes were found (haplotype diversity = 0.955; nucleotide diversity = 0.059). All of the haplotypes from Bulgaria and Romania formed a clade that was distinct from all of the Serbian and Greek haplotypes. At the estimated divergence time of 3.60 ± 0.58 ma a sea connection between the Pannonian Sea and Aegean Sea (at the site of the present Velika Morava Valley) formed a dispersal barrier for these freshwater snails. The nucleotide diversity within the Bulgarian/Romanian lineage was lower ( = 0.019, 41 polymorphic sites) that within the Serbian/Greek group ( = 0.049, 70 polymorphic sites), perhaps as a result of bottlenecks during the Pleistocene glaciations. Within the Bulgarian populations, all of the diversity originated in the Pleistocene, during the Calabrian (estimated time 1.26–1.42 ma). During the Pleistocene, the unstable system of rivers and lakes in southwestern Bulgaria, with glaciers in the Pirin and Rila Mountains, probably resulted in the extinction of Grossuana in SW Bulgaria. Subsequently, this territory was likely recolonized from eastern Bulgarian populations.

Description: Semisulcospira freshwater snails are a prominent element of the freshwater macrozoobenthos throughout East Asia and have undergone substantial diversification throughout Japan, particularly in ancient Lake Biwa. Up to 19 species are currently recognized in Japan, including a large number of endemics in Lake Biwa that are placed in the subgenus Biwamelania . However, previous workers have encountered pervasive polymorphism in morphological characters, rendering current species hypotheses tentative. Based on extensive sampling of populations from throughout Japan, followed by genetic characterization with one nuclear (28S rDNA) and two mitochondrial gene fragments (cytochrome c oxidase subunit I and 16S rDNA), the phylogenetic lineage differentiation of Semisulcospira in Japan is studied for the first time in an attempt to delineate species boundaries. The phylogenetic analyses revealed insufficient differentiation in 28S to address phylogenetic relationships amongst the Japanese species. While the mtDNA markers revealed substantial lineage differentiation, there was wide-ranging incongruence between the topology of the mtDNA-based trees and morphospecies. Moreover, there was no discernible phylogeographic structure. Haplotypes from the main mtDNA clades were found to be represented in nearly all Japanese regions, with Lake Biwa being a reservoir for every mtDNA clade. I conclude that mtDNA markers are unsuitable to address species limits in Semisulcospira from Japan and discuss polymorphisms in morphology and mtDNA plus introgression as possible causes for the observed incongruence, but without being able to identify its ultimate source.

Description: The Spheniopsidae are today represented by five living species of Spheniopsis and nine of Grippina , distributed in the Pacific and Atlantic Oceans. Little is known of their anatomy and the phylogenetic position of the family within the Bivalvia is debated. In order to investigate these questions, the functional morphology of Grippina coronata obtained from the continental shelf off Rio de Janeiro and Espírito Santo States, Brazil, has been examined. Less than 2 mm in shell length, the siphonal apparatus of G. coronata is complex, with seven sensory papillae, and the ctenidia are reduced to transverse septa pierced by four pairs of ciliated pores. There are no labial palps and the stomach is of Type II with epibenthic harpacticoid and ostracod prey identified inside it. Although there is an intestine producing faeces, the stomach also possesses a unique waste storage pouch for exoskeletal remains of digested prey. Collectively, these features suggest that the Spheniopsidae comprise carnivorous taxa belonging to the Cuspidarioidea within the Anomalodesmata. Grippina coronata is a self-fertilizing simultaneous hermaphrodite that, uniquely, broods fertilized oocytes within the ovarian follicles and, thereby, provides the first example of intrafollicular fertilization and brooding in the Bivalvia. Release of the encapsulated oocytes must be by parental death, which coincidentally releases the exoskeletal remains from the storage pouch. Such post mortem semelparity creates a life-history trait hitherto unrecognized in the Bivalvia.

Description: Littorina brevicula is one of the most common gastropods in the supralittoral zone around Japan. The northernmost population of this species is around Hokkaido and the determinant of this northern limit is likely seawater and air temperature. To reconstruct an evolutionary history of this species, we investigated genetic differentiation among 12 populations (three from Hokkaido, six from Honshu and three from Kyushu) using a mitochondrial DNA marker (partial sequence of the NADH dehydrogenase 6 gene). The haplotype network showed shallow genetic divergence within the species, suggesting a bottleneck followed by population expansion. One major haplotype that occurred in 70.5% of all individuals examined was the most frequent in every population sampled. A second major haplotype was abundant around Kyushu but not found in Hokkaido. This skewed haplotype distribution resulted in significant genetic differentiation along the north-south axis of Japan. The importance of the southern clade, which included the second major haplotype, was supported by population genetic analyses of datasets that excluded either the southern clade or the northern clades. The north-south differentiation remained when datasets that excluded the northern clades were used, but disappeared when datasets that excluded the southern clade were used. The combined evidence of shallow divergence and the north-south population structure suggests that the L. brevicula population around Japan once declined and then expanded and colonized northward. Although the time of population reduction and recolonization could not be precisely estimated, the observation that this species is absent further north in Japan suggests that it would have been unable to survive in northern Japan during the last glacial maximum (LGM) and therefore recolonization likely occurred after the LGM, probably from south to north.

Description: Fewer than 1% of marine gastropod species live a holoplanktic life. Of these, the shelled heteropods of the family Atlantidae are among the most poorly understood. The atlantids potentially make up an important part of the ocean zooplankton, composing up to 69% of shelled holoplanktic gastropods in the Late Pleistocene to Recent fossil record. They are also likely to be at high risk from current and future global changes, including anthropogenic ocean acidification. However, due to their small size (〈12 mm), difficulty of sampling and complicated morphology, we still lack key information about atlantid taxonomy and ecology. This makes it difficult to understand how important they are in the ocean foodweb and how they will be affected by environmental change. Although many studies have been carried out on the atlantids, these have generally been broad and unconnected. Here, we draw together this previous research, summarizing what is currently known about atlantid taxonomy, palaeontology, ecology and biogeography, and aiming to provide a foundation for future research on this group. The data indicate complex behaviours involving seasonal and vertical migration, and demonstrate extended geographical ranges, with implications for understanding the role of atlantids in the ocean foodweb and their sensitivity to environmental changes. This review highlights the urgent need for further taxonomic research on the atlantids, including molecular analysis, and for improved sampling techniques.

Description: Many ectotherms grow more slowly but mature at a larger size in colder environments, according to the pattern called the temperature-size rule. Thermal variation of cell size is suspected to be inherent in the origin of this pattern, but empirical testing of this hypothesis has been conducted in only a few taxa. In the laboratory, we reared two subspecies of the land snail Cornu aspersum (formerly Helix aspersa ), C. a. aspersum and C. a. maximum , at two thermal regimes (15 and 20 °C), aiming to examine the relationship between cell size and adult mass across temperatures. The warmer environment led to larger adult mass in both taxa, contrary to the temperature-size rule. Using histological techniques, we found that snails grown at the warmer temperature produced heavier shells, smaller muscle and epithelial cells, but larger hepatopancreatic cells and nuclei. These results strongly suggest that the temperature-size rule for body size cannot be explained by a simple consequence of thermal sensitivity of cell size. Focusing on the patterns between the two taxa, we found that aspersum grew more slowly, with faster metabolic rates and smaller mass at the end of the experiment, when compared with maximum , regardless of temperature. The subspecies aspersum evolved larger muscular and epithelial cells than maximum , but both had a similar size of hepatopancreatic cells and a similar shell mass. Interestingly, when compared across a range of small body masses, aspersum had a heavier hepatopancreas than maximum . We propose that the evolutionary divergence between the two subspecies might involve a trade-off between growth and hepatopancreatic functions, but not a trade-off caused by the costs of shell production and maintenance of cell membranes.

Description: Chemicals are the major means of control used against slugs, which are serious pests of various crops. To increase the sustainability of farming practices, alternatives that do not harm nontarget organisms are necessary. One area of investigation focuses on the capacities of prey to perceive their predators, which enables them to display antipredator behaviours. This study presents initial evidence of the potential effectiveness of using chemical cues from a predatory ground beetle to protect young oilseed rape shoots against a worldwide pest, the slug Deroceras reticulatum (Müller, 1774) (Stylommatophora: Agriolimacidae). A two-choice assay was used to test whether chemical cues from Carabus nemoralis Müller, 1764 (Coleoptera: Carabidae) could impede the foraging of D. reticulatum on young oilseed rape shoots. Significantly fewer cotyledons were consumed when chemical cues from the ground beetle were present compared with the control area, where slugs were mainly found. Chemical cues from predatory ground beetles appear to be a promising solution for protecting at-risk crops from the depredations of pest slugs.

Description: Larval development has strong impacts on dispersal potential and gene flow among populations of marine invertebrates. However, Pleistocene glaciations have also played an important role in shaping population structure in benthic taxa in the Northern Hemisphere, even those with planktotrophic larvae. Each glacial advance tended to fragment species distributions, often separating populations for long periods and setting the stage for their differentiation. This study examines patterns of sequence divergence of the mitochondrial cytochrome c oxidase subunit I gene in North American populations of two bivalve species complexes, Hiatella arctica s. l. and Macoma balthica s. l. , with complementary data from the nuclear internal transcribed spacer-2 (ITS2) gene for the latter. Our results confirm the presence of two known species from the M. balthica complex in Canada, but also provide evidence for a third clade in Atlantic Canada. Our study confirms that the H. arctica complex in Canada contains at least four species, with support for a novel clade ( Hiatella N) in the northeastern Pacific. Our results extend the range of a previously identified Hiatella clade (K) to include the northwestern Atlantic. Both M. balthica s. l. and H. arctica s. l. have broad Holarctic distributions and planktotrophic larvae, but this work reveals differences in phylogeographic structure and genetic diversity.

Description: Deposit-feeding gastropods provide integral links between benthic productivity and higher trophic levels in a variety of aquatic environments. At high population densities these snails can exert a significant grazing impact on available microphytobenthos (MPB). Here we provide the first report on the potential ingestion rates and feeding impact of the freshwater thiarid Melanoides tuberculata . This species consists of a variety of distinct morphs that have been introduced and become invasive in many areas in the New World. We used an in situ fluorometric approach to elucidate the feeding dynamics of three M. tuberculata populations from different habitat types. Daily ingestion rates, potential daily feeding impact and per capita resource availability were calculated based on snail density and MPB biomass. The highest maximum potential ingestion rate was estimated when snails occurred at the lowest population density, where per capita resource availability was highest. Feeding impact, in terms of potential daily consumption of MPB, varied depending on gut passage time and pigment consumption/digestion efficiency. Overall, the feeding dynamics of M. tuberculata were significantly different between populations. The variation in traits related to feeding dynamics, whether plastic or adaptive, contributes to the generalist nature of M. tuberculata . It is expected that these traits facilitate invasion success, as the species is able to inhabit and persist in a range of aquatic environments under different levels of resource availability.

Description: Vinclozolin (VZ) is an endocrine-disrupting chemical that is able to interact with the endocrine system of mammalian models directly via receptor-binding and indirectly via the epigenetic regulation of DNA methylation. Gastropods often respond sensitively to chemicals classified as endocrine disrupting chemicals, but information on epigenetics is almost absent for this group. In order to investigate potential phenotypic and epigenetic effects of VZ in gastropods, we performed a two-generation study with the freshwater snail Physella acuta. The parental generation (F 0 ) of P. acuta was exposed to 0.01, 0.1, 10 and 100 µg l –1 VZ. VZ-exposed F 0 and nonexposed offspring of the control, 0.1 and 100 µg l –1 groups (F 1 and F 2 ) were investigated for phenotypic (reproduction, growth and embryo development) and epigenetic (5-methyl cytosine content) effects. VZ exposure of F 0 did not induce an adverse reproductive phenotype in P. acuta . However, the size of F 1 adults and the mortality of F 2 embryos significantly increased when F 0 adults were previously exposed to 100 µg l –1 VZ. At the level of global DNA methylation, we did not observe a VZ effect, but global DNA methylation of P. acuta decreased with increasing age. VZ affected the offspring of 100 µg l –1 VZ-exposed individuals, most probably due to an indirect VZ exposure of F 1 (embryonic stage) and F 2 (germline). The postulated relationship between VZ phenotype and epitype was not shown by the present study. However, our results demonstrate for the first time the presence and age-dependence of DNA methylation in P. acuta .

Description: Crassostrea oysters show intraspecific variation in sexuality, including dioecy as well as sequential and simultaneous hermaphroditism, but their sexuality under natural conditions has rarely been reported. We examined sexuality and the effects of body size and gregariousness on sexuality in a natural population of the Pacific oyster C. gigas in southern Japan. First, monthly samplings were made during their reproductive season (May–August 2012) to study the sex of wild individuals. The proportion of males was found to decrease with increasing shell length (SL) and was greater in gregarious than solitary individuals. Simultaneous hermaphrodites were encountered infrequently ( c . 1%). The negative relationship between the proportion of males and SL was also observed among the new cohort that had settled within one year. Next, we directly observed sex change by inspecting the sex of the same individuals through biopsy in two consecutive years (2013–2014; long-term experiment) or within a reproductive season (May–August 2014; short-term experiment) in the same population. Manipulation of the gregariousness (whether solitary or gregarious) was also conducted at the beginning of the experiments. When the individuals were re-collected, sex change in both directions was observed both in the long- and short-term experiments. Moreover, sex change from male to female was promoted when individuals were made solitary rather than gregarious. In summary, our study has shown that C. gigas has a tendency for protandry and has the ability to change sex in both directions under natural conditions in an area where they are native. Although within-season sex change of Crassostrea species has heretofore been unknown, C. gigas can change sex even in the short term. We suggest that such plasticity and the resulting diverse sexuality may be adaptive for sessile organisms such as oysters.

Description: The distribution of the lagoon cockle Cerastoderma glaucum is strongly fragmented and usually restricted to isolated, shallow and nontidal lagoons. A high level of genetic structuring was found among the European populations of this species based on mtDNA (COI) sequences, as well as allozymic and microsatellite markers. However, the strengths and geographic locations of the major divisions differed among markers. In the present study we characterized the diversity of a new, potentially universal exon-primed intron-crossing marker, i34, for 17 C. glaucum populations. Allele frequency data at the i34 locus were informative and relevant with respect to geography. Multivariate analyses of new data together with previously published microsatellites confirmed the divergent character of the Ionian Sea and the Aegean-Ponto-Caspian populations, but also revealed the existence of a genetic cline from the Bay of Biscay to the Baltic Sea. Some noncongruent patterns among loci were detected, which may reflect either differential introgression along the genome at the hypothetical contact zone, or selective sweeps. This strong genetic differentiation, and the occurrence of private alleles, may hint at the presence of cryptic species within C. glaucum .

Description: The complete mitochondrial genome of the neotype of Cerion incanum ( Leidy, 1851 ) was sequenced using high-throughput sequencing and found to be a circular genome 15,117 bp in length with a GC content of 34.3%. It is the largest mitogenome presently known in Stylommatophora, with the difference in size due primarily to intergenic regions and to a lesser extent to larger sizes of individual genes. Gene content is identical to that of other stylommatophorans, but differs in having the tRNA-Gln gene situated on the major coding strand. Gene order of C. incanum was similar to that in Helicidae, differing in the regions between COX1 and NADH5, and between tRNA-Ser2 and tRNA-Ile. The potential origin of replication was located in a 50-bp noncoding region between COX3 and tRNA-Ile. Phylogenetic analyses using Bayesian inference and maximum-likelihood analyses of nucleotide data for all protein-coding and large and small ribosomal genes resulted in a well-resolved tree. This tree was similar to trees derived from nuclear or a combination of nuclear and mitochondrial genes, differing from previous phylogenetic reconstructions based on mitogenomes in the placement of Hygrophila. The phylogenetic position of Cerionidae as sister taxon to Helicoidea is consistent with previous findings after allowing for more limited taxon sampling in the mitogenome tree. The mitogenome tree is sufficiently populated to refute the inclusion of Cerionidae in Clausiloidea, as advocated by some authors, but at present lacks the representatives of the Orthalicoidea or Urocoptoidea needed to resolve more precisely its relationships with those taxa.