The two land snail species Trochulus striolatus (C. Pfeiffer, 1828) and Xerocampylaea erjaveci (Brusina, 1870) are distantly-related within the Hygromiidae, and while geographically separated, have similar habitats. They are conchologically very similar in their shape. The growth, reproductive strategies and life histories of these species reared under constant laboratory conditions were studied in order to detect any similarities and differences between the species. In both species, isolated individuals did not reproduce; thus, uniparental reproduction appears not to occur. While morphological characteristics, such as the egg size and number of whorls at hatching and at sexual maturity, were relatively constant and similar in both species, there were differences in terms of the growth rate, age at first reproduction, output of eggs over the lifespan and in the pattern of mortality. While the range of variation within species was much greater in relation to these traits, it appears that X. erjaveci grows faster than T. striolatus : they become adults earlier; they have a shorter lifespan as adults, but less juvenile mortality; and individuals lay many more clutches, over a similar time span, laying more than five times as many eggs as T. striolatus over the course of the experiment. Under these admittedly artificial conditions, the individuals of both species (although more so in X. erjaveci ) can lay more than one clutch over a period of more than two years, in an environment where no winter conditions were imposed. These results, which can also be compared with similar data for Trochulus hispidus , a species closely-related to T. striolatus, emphasise the fact that life histories, even among species of a similar size and habitat, may differ considerably. They also illustrate the difficulties inherent in laboratory studies of life histories.

Repeat surveys of the shell colour and banding polymorphism in populations of the land snail Cepaea nemoralis in the cities of Sheffield (UK) and Wroclaw (Poland) and in its surrounding settlements were made after a 13-18 years interval. In all three cases, a substantial proportion of sites had been destroyed by development (18-30%) and a similar proportion no longer held the species, despite being apparently suitable; up to 50% of populations had disappeared. Overall, the pattern was one of stasis in morph-frequencies, and of little change in the range of variation as estimated by a modified version of Fst. There were, however, substantial changes in some populations, not consistent in direction, but larger than expected from sampling error. While there was tenuous evidence for selection against yellow shells, the large changes are attributed to bottlenecks, founder effects, and possible local extinction and recolonisation. Urban populations are often transitory and the results are contrasted with those from an area of long-term habitat stability and population connectivity. Newly established and sometimes transitory populations offer opportunities to study underestimated aspects of evolutionary processes.

Variation in the shell colour and banding polymorphism in populations of the land snail Cepaea nemoralis was studied in the towns of Skara (central Sweden), and Kudowa Zdrój (south-west Poland), both recently colonised by the species. In both towns, populations were highly polymorphic; populations in each did not differ from each other as much as in cities recently invaded. Population density was higher in Kudowa, and its populations were both marginally more polymorphic and differed less among each other than at Skara. A single introduction followed by local spread seems the simplest explanation of the patterns observed. There was no evident geographical pattern in either case, suggesting that leptokurtic, passive dispersal plays a role, even at a local scale.

The land snail faunas of limestone gorges of Romanian Carpathians were sampled to test the effect of geographic and environmental factors on the malacofauna richness and composition. A total of 134 sites within 28 limestone gorges were surveyed during 2011–2019 using a combined strategy of visual search and litter/topsoil analysis. Environmental variables such as geographic location, altitude, climate, microhabitat type, dominant vegetation, tree cover and width of the gorge were recorded to detect the relationship with species richness and composition. While the numbers of species, their identities and their abundance varied greatly among samples, both presence and absence data and quantitative multivariate analyses showed that region and climate or altitude (both strongly associated with region) accounted for far more variation than differences in tree cover and dominant microhabitat. Nevertheless, the effects of different habitat preferences were evident. The mixture of species with very restricted ranges within this Pleistocene refugium and those that have spread widely during the Holocene raise questions about the meaning of region when related to local richness and composition.

Aim: Island biological communities are considered to comprise non-random assemblages from surrounding source pools, but whether they converge towards predictable structural properties remains unclear. Here, we (i) test whether insular communities of land snails converge towards similar functional and/or taxonomic properties and (ii) evaluate whether island functional diversity is determined by island biogeographical characteristics such as area and distance to the pool as well as human-related variables.Location: Sixty-six continental Aegean islands.Taxon: Land snails.Methods: We compiled a database of two morphological traits with functional significance (shell height and width) for 163 island species and 1529 species from the major species pools. We quantified inter-specific morphological dissimilarity between pairs of islands (turnover), using a modified index of the mean nearest taxon distance. We tested for functional and taxonomic convergence using null models and assessing whether overall mean turnover among islands and pairwise island-by-island turnover were lower than expected by chance. We performed multiple regression analyses to test whether functional diversity metrics scale with island biogeographical characteristics and human-related variables.Results: Our analyses provide strong evidence that communities of land snails across the Aegean islands converge towards non-random functional properties and taxonomic structure. At the island level, a wide range of different shell shapes is observed, indicating greater functional richness than expected by chance. Regression analyses showed that island area is the only efficient predictor of functional diversity, indicating that available ecological/resource space is of central importance in driving the assembly of different shell shapes.Main Conclusions: Our findings, consistent with previous studies of other taxa from oceanic islands, highlight that island species communities are not randomly assembled and display convergence in their functional and taxonomic composition. Integrating functional diversity metrics within biogeographic analyses has the potential to further our understanding of island biodiversity patterns.

While varying greatly in size, European clausiliids have a remarkably consistent and characteristic shell form that distinguishes them from all other land snails in the region. They are found in a wide range of habitats and are geographically widespread, occurring in boreal through to mediterranean climates. There are, however, regional differences in species richness and range sizes, and striking differences in the number of species that may be found syntopically, even in habitats that appear similar. Regions of high diversity do not always support many species co-occurring at site level. We explore these differences, using information on habitat and microhabitat differences between species to assess the extent to which co-occurrence might be limited by competition or environmental constraints. Neither provide a satisfactory explanation for all patterns, and the effects of Quaternary climate change and limited powers of dispersal are clearly important.

Fruticicola fruticum (O. F. Müller, 1774), a medium-sized helicoid snail in the Camaenidae, has a wide range in Europe, reaching from the Urals and the Caucasus to the Balkans, and from the southern part of Scandinavia, through Central Europe to eastern and central France and northern Italy. There are numerous studies on its distribution, biology, life cycle, etc., but little is known about the genetic diversity of this taxon. Here, we studied the phylogeny and phylogeography of F. fruticum using two mitochondrial markers: cytochrome oxidase subunit I (COI) and 16S ribosomal RNA (16S); and four nuclear markers: 18S ribosomal RNA (18S), 28S ribosomal RNA (28S), internal transcribed spacer (ITS-2), and histone 3 (H3). The study was based on 59 populations sampled across the range. Whereas nuclear markers showed little differentiation, phylogenetic analysis of COI sequences clearly confirmed the distinctness of the European Fruticicola and Asian Bradybaena (p-distance 0.229). Within Fruticicola 54 haplotypes were detected, haplotype diversity (Hd) = 0.973 ± 0.006, nucleotide diversity (π) = 0.137 ± 0.005. ABGD and PTP delimitation analyzes distinguished eight mOTUs. Two sequences (our mOTU C) from Russia were published in the GenBank as two distinct species: F. schrenckii and F. transbaicalia. Seven further mOTUs identified in our study formed three distinct lineages, regarded as species. The first (mOTU A and mOTU B), represented by 40 populations, occupies a wide range across northern and central Europe, extending east to Ukraine and south to northern Croatia (mOTU B). It encompasses the type locality of F. fruticum, and can be recognized as F. fruticum sensu stricto. Another lineage (mOTU D and mOTU E), represented by six populations in central Romania, appears to form another species. Both mOTUs were found together in one population. A third lineage, containing mOTUs F, G and H, represented by 14 populations, was distributed across the Balkans from N.E. Croatia to Bulgaria. p-distances between the three species ranged from 0.172 to 0.219, and between all the mOTUs, pooled together, from 0.172 to 0.258. The highest genetic diversity was found in species 3 (0.112) and the lowest in species 1 (0.025), despite its largest geographic distribution. Pairwise p-distances, Tamura 3-parameter distances, composite likelihood distances, as well as the coancestry coefficient FST, calculated for all populations pooled together were significantly associated with geographic distance, but this was not the case within each of these three species. The significant association for all populations reflected high diversity between the species coupled with high geographic distances between their populations, not the character of intraspecies diversity. With a few exceptions, there hold a rather infinite island model with low migration. AMOVA detected 78% of the variance between the three species, 18% among populations within the species, and only 3.6% within the populations. The low genetic diversity of widespread F. fruticum s. stricto, compared with much higher diversity of two narrowly distributed newly found species of Fruticicola, may reflect the rapid spread of the former into previously uninhabitable regions, while the latter were able to maintain populations in glacial refugia. The estimated time of divergence between the three species, 1.7-2.19 mya, suggests their ancestors' isolation in southern European refugia during the lower Pleistocene, the Gelasian/Calabrian. There was no clear association of variation in shell morphology and lineage or mOTU identity; on external characters, these species are semicryptic, subtle differences in reproductive anatomy among them were found.

ABSTRACT Late Quaternary deposits containing fossil snail shells were sampled from nine sites on Deserta Grande and three on Bugio, two of the three Desertas Islands in the oceanic Madeiran archipelago. In total, 3,432 shells representing 45 species or subspecies were retrieved. Calibrated amino acid racemization yielded ages ranging from >45 to 6 ka, with variation by site often confounded by reworking of mostly colluvial deposits. The assemblages found are compared with the extant fauna, itself a subject of intensive recent study. Of the 45 taxa, 18 are apparently extinct, and a further 5 no longer survive on the Desertas. A similar pattern emerges when each island is considered separately. The level of local extinction (c. 50%) is greater than seen on the larger, nearby islands of Madeira and Porto Santo. There are few endemic species in the extant fauna not represented in the fossil assemblages, but there are a number of possibly adventitious species, some with wide distributions in Europe. There is little evidence of faunal change within the limits of the age range available, and extinction seems to be concentrated in the later Holocene. It is attributed to the massive habitat destruction that occurred subsequent to human occupation from the 15th century CE onwards. The study emphasizes the depauperate nature of many extant island faunas subject to human disturbance.

A revised and annotated checklist of the living and Quaternary land snails of the Desertas Islands, Madeiran Archipelago, is presented, incorporating recent published work and records previously unpublished. 55 species have been recorded on the Desertas, of which 36 were alive and 41 were found as Quaternary fossils. Only four species are widespread and not endemic to the Archipelago; 14 are endemic to the Desertas. 19 species are known only as Quaternary fossils from the Desertas, of which eight remain extant elsewhere in the Archipelago. Three species, Leptaxis groviana, L. simia and Discula polymorpha, are represented on the Desertas by more than one subspecies, although this status has not been confirmed by molecular studies. Records of a further seven species appear doubtful but are listed here.

Among ten adult specimens of the Madeiran endemic land snail Leptaxis simia kept in the laboratory, a single clutch of 110 eggs was reared, and the mortality, growth and reproductive capacity of hatchlings over a 1240- day period were monitored. Of 70 hatchlings, 34 survived to complete shell growth at around 640 days. Growth was rapid, and mortality high in the early stages; growth slowed and mortality was very low as full size was approached. Snails kept singly failed to lay any eggs. Among those with potential mates, only three clutches were produced, one of which yielded no hatchlings. Clutches were produced at least five months after shell growth was complete. Mortality increased sharply after the onset of sexual maturity, and the oldest snail survived for three and a half years. The apparently very strictly semelparous mode of reproduction, delayed sexual maturity and relatively long period of juvenile growth are discussed in relation to other species, and to the practical problems of rearing potentially endangered species in captivity.

Highlights• Despite much interest in insular snails, it is not known how many island snail species there are, or how many are endemic to single islands and/or specific island regions?• We address these questions by collating the first global database of insular land snails.• Although hosting almost 50% of the known land snail species and 82% of the known families, the 727 islands represent just about 3% of global landmass.• Seven large islands comprise almost 50% of global single-island endemics richness.• Our database represents one of the few attempts to quantify global invertebrate diversity on islands, and thus serves as a plea to intensify research efforts towards describing and understanding the patterns and processes establishing invertebrate biodiversity at large spatial scales.

Trochulus is a genus of European land snail with a complex and disputed taxonomy and an intricate evolutionary history. Many species and subspecies were described only on the basis of shell morphology, which is highly variable, such that the shell morphology of many species and subordinate taxa appear to overlap that of others. In resolving the phylogeny and nomenclature of the genus, it is crucial to study type material, which is often not available. Examination of Locard's material from the Museum national d'Histoire naturelle (MNHN) in Paris (France) led to the discovery of two specimens of Helix abludens, Locard 1888. This material is considered to belong to the original lot used by Locard to define his species, which was regarded as Trochulus striolatus subsp. abludens but recently discarded. In order to definitively clarify its identity and to stabilise the name, the best-preserved specimen is selected and designated herein as a lectotype. It is fully described and illustrated. The other specimen from the same lot becomes a paralectotype. This designation allows the restriction of the type locality to Boulogne-sur-Mer in the department Pas-de-Calais in France.

Cepaea nemoralis is a recently introduced species on Öland. Discounting an early and debateable record, the species has been recorded only in the 21st century, despite intensive earlier faunistic surveys. A recent survey has yielded records from the whole length of the island (137 km), but the majority of known populations are in its southern half, most particularly around the settlements of Mörbylånga, Gräsgård and Färjestaden. Populations are usually in anthropogenic habitats. Most appear small and isolated by less disturbed areas. Nearly all samples are polymorphic for both colour and banding morphs, and the variation among populations is low when compared with similar sets from other places where recent colonisation has occurred. There is no latitudinal variation in morph frequencies, nor is any spatial autocorrelation apparent. While a relatively uniform and rigorous selection regime could account for the patterns seen, a single initial introduction followed by transport of propagules large enough to minimise founder effects is also possible.

Melanopsidae were collected from 23 localities in central and south-eastern Europe, the Aegean Islands and Israel. This study considered Melanopsis from the Aegean Islands, the Peloponnese and Israel, and Esperiana esperi, Holandriana holandrii and Microcolpia from continental Europe. Shells and radulae were described and illustrated, showing continuous variation of shell characters and differences in radulae among genera. Phylogenetic analyses were conducted on single-locus datasets (COI, 18S, 28S, ITS2 and H3) and on a concatenated dataset. Molecular data showed a differentiation not paralleled in morphology, reflecting morphostatic evolution. In all species with ribbed shell-forms, the ribbed and unribbed forms did not differ genetically. Within Melanopsis, four clades representing five species were distinguished. Melanopsis buccinoidea is found in Khios and Lesbos Islands, M. astropaliae in Naxos, Samos and Tinos Islands, M. wagneri in Rhodes Island and the Peloponnese, and M. costata and M. saulcyi in Israel. Molecular results and the ICZN rule of priority restrict the range of M. buccinoidea to the North Aegean Islands. ‘Melanopsis’ parreyssi belongs to the genus Microcolpia. Esperiana esperi belongs to a clade separate from Microcolpia.

1. Cain A. J., Sheppard P. M. 1954. Natural selection in Cepaea. Genetics 39: 89–116. Google Scholar

New sites containing fossil-rich Quaternary deposits have been discovered on Deserta Grande and Bugio, islands in the Madeiran Archipelago, Portugal. Examination of these, together with a reassessment of earlier collections, has led to the identification and description of 6 new species and 2 new subspecies. The revised taxonomy involves species in the genera Leiostyla (Lauriidae: desertaensis n. sp., simulans n. sp., cooki n. sp., castanheiraensis n. sp.), Actinella (fecundaerrata n. nom.), Discula (cameroni n. sp., polymorpha docaensis n. ssp.) (all Geomitridae), and Leptaxis (Hygromiidae: isambertoi n. sp., groviana antiqua n. ssp.). In addition, lectotypes are designated for Helix pittae Paiva, 1866, Helix actinophora var. beta descendens Wollaston, 1878, and Helix vulgata var. epsilon saxipotens Wollaston, 1878, and the latter 2 am elevated to species rank. Their binomial names are now Caseolus pittae, Actinella descendens, and Actinella saxipotens. For Helix senilis var. gamma pusilla R.T. Lowe, 1855 a neotype is designated, and the new name Actinella fecundaerrata given to replace the pre-occupied name. Further notes are given on findings of species of the genera Cecilioides (Ferussaciidae), Helicomela, Geomitra, and Spirorbula (all Geomitridae) on the Desertas Islands.

A countrywide data set of 1048 samples of the European land snail Cepaea nemoralis (L.) from Poland was assembled from both published and unpublished sources. Analyses of shell colour and banding polymorphism revealed distinctive patterns of variation. While the frequency of brown shells showed a clear geographical pattern related to climate, other morphs showed no such clear trends. Variation among populations was great, but little of this could be accounted for by variation among regions. Spatial autocorrelation was generally restricted to very short distances, of the order of 20 km or less. Variation with habitat was found in the form of an excess of brown shells in shaded habitats and an excess of yellow and yellow effectively unbanded shells in open habitats, although this was not universal. The data suggest that cases of long-distance, passive dispersal followed by more local spread account for much of the variation, and that strong selection related to habitat may be obscured by different sources of populations within a few kilometres of each other. The data are now available to track changes over time.

The polymorphic land snail Cepaea hortensis was introduced to the city of Sibiu, central Romania, in the first decade of the 20th century and has spread widely across the city. A total of 97 locations were examined in 2017 across the city to determine the habitat preferences and variation in shell size, shape, colour and banding polymorphism of C. hortensis, and to relate these to the same features in the likely source population from Mannheim, Germany, and the first established population in Sibiu. We found that C. hortensis was largely restricted to sites with some woody vegetation cover and showed a marked preference for abandoned and overgrown private gardens. Mean adult shell size in present-day populations was almost always smaller than in both the presumed population of origin from Germany and the first recorded population from Sibiu. Populations showed a wide range of variation in frequencies of shell colours and banding morphs. This variation was not related to habitat or cover, and there was no evident geographical structure in the patterns. Comparisons with a smaller-scale sampling in 2004/5 showed that some populations had gone extinct, some remained stable and in some morph frequencies had changed drastically, but in no consistent direction. These results are similar to those obtained for the related species C. nemoralis in comparable circumstances, but differ from those obtained from regions where C. hortensis is long established and where habitats have been stable. The patterns we observed most likely reflect the effect of passive dispersal by humans, genetic drift and founder effects.