Distributions of some plants and animals have already shifted in recent years due to climate warming, and climate warming has potential to extirpate populations of taxa that cannot easily move or adapt to changes in temperatures and/or moisture. This study in Pennsylvania, U.S.A. focuses on whether snail populations currently confined to cooler habitats at higher elevations (elevations 700–978 m comprise only 2% of Pennsylvania's area) might decline or be eliminated if their ranges are reduced upward by climate warming. We examined whether some land snail species are limited to upper elevations in order to assess whether climate warming poses a threat to them. Sampling included 108 sites across Pennsylvania, comprising 12 localities at each of nine elevations from 100 to 900 m elev. Overall numbers of snail species and abundances decreased at greater elevations. Most individual species tended to occur throughout sampled elevations or occurred primarily at lower elevations, so the reduced altitudinal range aspect of climate warming might not threaten them. However, five species occurred significantly more often at greater elevations suggesting that their populations might decline if climate warming were to reduce their ranges upward. Four additional species including three native slugs showed non-significant trends to occur at higher elevations. These species might be monitored into the future.

Two species of genus Helix Linnaeus, 1758 (Mollusca: Gastropoda: Helicidae) endemic to the Caucasus region are known from Georgia and northeastern Turkey: Helix buchii Dubois de Montpereux, 1839 and the recently-described but disputed Helix goderdziana Mumladze, Tarkhnishvili and Pokryszko, 2008. The latter species is the largest land snail throughout non-tropical Eurasia. We compared shell shapes and genital morphology of the two species. We analyzed mitochondrial COI and nuclear 18S ribosomal RNA and ITS1gene fragments in 39 specimens of H. buchii and H. goderdziana from ten locations from the entire distribution range of these species, together with 13 specimens of the widespread H. lucorum Linnaeus, 1758 and H. pomatia Linnaeus, 1758. Based on shell morphology alone, most of the individuals of the two species can be discriminated using multivariate approaches. The species have different flagellum/diverticulum ratios, and the foot coloration is a fully diagnostic morphological character. Molecular genetic analysis revealed little variation in 18S ITS1 fragment, and eleven COI haplotypes. Phylogenetic analyses support reciprocal monophyly of H. buchii and H. goderdziana. The genetic distances significantly correlate with the geographic and morphological distances; correlation of morphological distances with geography is insignificant. The basal lineages of both species are found within two distinct glacial refugia, a result which matches the separation of eastern and western evolutionary lineages of other relicts of the Western Caucasus. The present distribution of H. goderdziana coincides with the expected refugiai borders, whereas H. buchii is likely to have extended its geographical range since the last glaciation.

The systellommatophoran slug Veronicella sloanii (Cuvier, 1817), is a simultaneous hermaphrodite. This slug is an agricultural and horticultural pest in Barbados and several islands of the Lesser Antilles. Over the period January-July 2006 and June-August 2010, the mating behavior of this species was determined by ad libitum and focal animal sampling of captive slugs collected from six sites on the island of Barbados, supplemented by observations and length measurements of slugs seen mating in the field. Individuals of Veronicella sloanii mated reciprocally in pairs, but also in a multi-partner ring formation involving three individuals. Two stages in the mating process were identified, courtship and copulation. Courtship was short, less than two minutes in mating events that led directly to copulation (mean 1.87 minutes, range 0.25–2, N = 53). Copulation in contrast was long, lasting on average 1.03 hours (range 0.4–2, N = 40). During mating the penial gland of each partner made contact with the foot or the hyponotum of the other partner. Aggressive behavior during mating in this slug was manifested by non-mating individuals pushing themselves between mating pairs resulting in the withdrawal of the penis of the mating pairs and cessation of copulation. A strong size-assortative mating pattern was observed; individuals in mating pairs were of similar size.

This paper reports for the first time the occurrence of four exotic terrestrial slug species in Argentina: Lehmannia valentiana (Férussac, 1823) (Limacidae), Deroceras invadens Reise et al. 2011 (Agriolimacidae), Arion intermedius Normand, 1852 (Arionidae) and Meghimatium pictum (Stolyczka, 1873) (Philomycidae). The study is based on specimens deposited in museums in Argentina. Both the morphologic characteristics and the mitochondrial cytochrome oxidase I gene sequences were used to identify the exotic species. Phylogenetic analyses were also carried out in order to explore the location of their origins. Lehmannia valentiana had the oldest records and has been widely distributed in Argentina. Deroceras invadens and A. intermedius were found to be restricted to the southern portion of the country. Meghimatium pictum was recorded in the northwest and northeast Argentina, and the DNA sequences analyzed from this species were more closely related to specimens from the west of the Strait of Taiwan. A determination of the origin of the other species was impossible because either the sequences analyzed grouped with samples from different geographical origins or only few sequences were available for comparison. In view of the invasive potential of these slug species, the present work provides new and potentially useful DNA sequence data obtained from morphologically-confirmed specimens. Information provided from these analyses should assist in making a rapid identification of these exotic slugs by nonspecialists and governmental authorities who are responsible for managing and controlling the presence of exotic species.

The phylogenetic relationships of species of the mussel genus Ptychobranchus Simpson, 1900 were examined using the mitochondrial DNA sequences of the ND1 and 16S gene regions. A total of 31 individuals representing the five species are included in this analysis. Outgroups were drawn from other unionid genera previously shown to be closely related to Ptychobranchus. Phylogenetic analysis was conducted using Bayesian methods applying several data-partitioning strategies. The results of all analyses support the monophyly of Ptychobranchus, and the interrelationships of its constituent species are consistent across all analyses. Ptychobranchus occidentalis (Conrad, 1836) is recovered as paraphyletic with P. fasciolaris (Rafinesque, 1820). Molecular analyses indicate that Ptychobranchus jonesi van der Schalie, 1934 is a member of the genus, and character state reconstruction predicts that it should possess the complex conglutinate that is found in other species of Ptychobranchus.

Following the retreat of the last Pleistocene glaciers ∼10,000 years before present, aquatic organisms re-colonized previously uninhabitable regions from various glacial refuges. Glaciations had major impacts shaping patterns of genetic diversity and population structure for organisms throughout North America. Knowledge of genetic population structure is critical for successful conservation programs involving an increasingly threatened freshwater fauna. Due to variations in life history and ecology, species-specific planning may be the most effective method for preserving rare or threatened species. The Ellipse mussel (Venustaconcha ellipsiformis) and its congener the Bleeding Tooth mussel (V. pleasii) are species of conservation concern through much of their respective ranges in the Midwestern United States. The Ellipse is found in small to medium rivers from the northern Ozark highlands north to the Upper Mississippi River drainage and into tributaries of Lake Michigan and Lake Huron. Mitochondrial DNA from the COI and ND1 regions was amplified to assess the genetic diversity and structure of these species. Phylogenetic analyses confirmed that V. ellipsiformis and V. pleasii are distinct species. Little variation was recovered in the Ellipse with a single common haplotype dominating throughout its range. For Ellipse, only limited genetic differentiation was found among the geographic regions sampled, with consistently significant differentiation only found between populations in the Illinois River drainage and populations in the northern Ozarks. The general low to moderate genetic structure among various geographically distant Ellipse populations suggests this species dispersed rapidly from unglaciated refugia with little time for genetic isolation to occur. The data suggest that V. ellipsiformis populations should be treated as three separate management units: northern Ozark highlands, Upper Mississippi River drainage, and the Illinois River/ Great Lakes drainages.

Bacteria are ingested by suspension feeding bivalves and can be an important component of their diet. This study evaluated whether a common bacterium of vertebrate enteric origin, Escherichia coli (Migula, 1895), is retained in the stomach or gill by two different freshwater bivalve species, Corbicula fluminea (Müller, 1974) and Elliptio complanata (Lightfoot, 1786). A series of diet treatment experiments were conducted comparing each anatomical section using a δ¹³C label and E. coli cells grown from stock cultures. A significant difference in δ¹³C values was related to anatomic structure among all treatment groups during a 7-day feeding experiment (24 jars, df = 140; F = 4.88; P < 0.001). A key finding was that in gill tissue, a significant difference was observed among <δ¹³C-labeled and unlabeled treatment combinations for both C. fluminea and E. complanata (F = 13.57; df = 31; P < 0.0001). The results suggest that water column E. coli are likely retained on gill tissue and to a lesser degree in the stomach in both E. complanata and C. fluminea. This study serves to validate the hypothesis that E. coli may be initially more abundant in gill tissue during sorting processes before being transferred to the stomach.

Four nystiellids belonging to the genera Eccliseogyra Dall, 1892, Opaliopsis Thiele, 1928 and Papuliscala de Boury, 1911 were collected on the continental slope off Brazil during the development of the REVIZEE Program (2000–2001). Of these Opaliopsis atlantis (Clench and Turner, 1952) was the only species known previously. Three nystiellids unknown to science, belonging to the genera Eccliseogyra and Papuliscala, are presented herein based on shell morphology. Eccliseogyra maracatu sp. nov. and Papuliscala nordestina sp. nov. are described for northeastern Brazil. Only one specimen of Eccliseogyra sp. with damaged shell was found. A formal epithet for this specimen will be delayed until additional material is collected. A checklist of species of Nystiellidae Clench and Turner, 1952 known for the Atlantic coast of South America, as well as their geographic and bathymetric distribution based on data from the literature, is presented.

Fossil and Recent shells of Turritella leucostoma (Valenciennes, 1832) are common in the Northern Gulf of California and, during winter months, living specimens can be found populating tidal flat environments. At San Felipe, Baja California, Mexico, T. leucostoma preferentially inhabit the sediment near the base of tidal channels and the low tide beach, where a total of 45 live specimens were gathered and documented. Most specimens were found in feeding position with the aperture exposed at the sediment surface and the apex pointed down at a low angle into the sediment. They act as predominantly stationary semi-infaunal active suspension feeders. Actively moving specimens were encountered during day and night low tides. The size distribution of the shells is narrow and no juveniles occur on the San Felipe tidal flat. Analysis of δ¹⁸O performed on three shells shows variations of up to 3.4‰ attributable to seasonal changes in water temperature, and indicates longevity of 1.5–2 years and relatively constant growth rates. The carbon isotopic composition of the analyzed shells suggests that the individuals moved from a deeper environment to a tidal flat environment after their first year of life where they may have been subject to a change in diet and ambient dissolved inorganic carbon composition and/or began to incorporate more isotopically-light respiratory carbon into the shell.

Ostrea puelchana d'Orbigny, 1842 is a common species of commercial interest in Patagonia and is distributed from Rio Grande do Sul (Brazil) to San Matías Gulf(SMG, Argentina). In SMG, the species develops natural banks that provide irregular surfaces suitable for colonization of organisms. We studied the composition and frequency of encrusting and associated species on O. puelchana shells as well as the preferential settlement of epibionts on different areas within left and right valves. A total of 55 taxa were identified. The dominant groups were Annelida, Foraminifera, Bryozoa and Mollusca in two different oyster banks. The lifestyle of the oyster favors a preferential settlement of epibionts on different valves and areas within the valves. Substratum heterogeneity, reproductive cues, gregarious behavior, protection against predation and/or brooding care could be responsible for this differential settlement. The left valve was more encrusted than the right one. Spirorbinae, Cirratulidae, Foraminifera, juvenile O. puelchana, Bryozoa and Hydrozoa showed preferential settlement in different areas on the external left valves. On the external right valves, the same taxa except for Hydrozoa showed a nonrandom distribution between areas.

During the research of fen mollusc assemblages in Switzerland carried out in August 2012, we recorded the first occurrence of Vertigo lilljeborgi (Westerlund, 1871) in the Alps and several new occurrences of V. genesii (Gredler, 1856), substantially extending its Alpine distribution island towards the western part of the mountain range. Both these Euro-Asian species are mainly distributed in northern Europe and have a strong ecological affinity to groundwater-fed fens. With respect to the rarity, refugial character and high conservation value of central European populations of these species, we review in detail their ecological preferences and present European distribution, and also comment on the possible conservation implications for their globally threatened habitats.

Lunatia heros (Say, 1822) is a common predatory gastropod in soft-sediment marine environments along the northwestern Atlantic coast. While recognized as a major predator of several commercially important molluscs, little is known about the diet breadth of L. heros and the potential of this species to exploit a broader range of molluscan taxa. Here, using a forensic approach based on beach-collected shells, we document prey species drilled by L. heros in eastern Cape Breton, Nova Scotia, Canada, and compare our findings to those reported in the literature for this species. Our results indicate that L. heros consumes a wider range of prey species than the fifteen currently reflected in the literature. In beach surveys, representatives of twenty of the twenty-eight molluscan species collected were found with beveled boreholes, nine of which were previously unreported as prey items of L. heros. Our findings thus confirm the generalist feeding tendencies of this species and increase the number of recorded prey taxa drilled by L. heros from fifteen to twenty-four. Further studies of the diet, feeding behavior, and foraging ecology of L. heros should ultimately lead to a more comprehensive understanding of this predator and its role in benthic soft-sediment marine environments of the northwestern Atlantic.

A Conus californicus Reeve, 1844 is reported killing and attempting to feed on the nudibranch Triopha catalinae (Cooper, 1863). This is the first documented case of a predatory cone killing a nudibranch. The impact of cone attacks on nudibranchs populations is unknown, but this note may lead to further research on this topic. Because conotoxins appear to have an effect on the nudibranch nervous system further research on the interaction between conotoxins and nudibranchs could be a source of important discoveries.

A new species of aeolid nudibranch is described based on specimens collected in the tropical western Atlantic Ocean, from Cubagua Island, Venezuela. The species belongs to the genus Learchis Bergh, 1896. The rhinophoral shape, and body and ceratal coloration are distinct from other previously known species of the genus.