Land Snail Research Articles

A new species of Petraeomastus Möllendorff, 1901 (Gastropoda: Stylommatophora: Enidae) with a varied shell from the Daduhe River Valley in southwest China

AbstractA new enid land snail, Petraeomastus liuzhengpingi Z.-G. Chen & Z.-Y. Chen, sp. n. is described from Danba County, Sichuan Province, China based on shell and genital morphology. The new species displays a varied shell morphology with some individuals exhibiting a completely detached last whorl, which is the first record of this phenomenon in the family Enidae. The discovery contributes to our understanding of the high species diversity of Enidae in the dry-hot river valleys in China.

What do Lateglacial and Holocene land snail communities tell us about the palaeoenvironments of Mediterranean France?

Southeastern France occupies a key biogeographical position on the lower Rhone corridor, at the interface between southern and northern Europe. It is also at the heart of long‐standing ecological debates about the respective roles of natural and human drivers in shaping the Mediterranean landscape. Molluscan analysis may represent a valuable contribution to this issue. In this paper, land snail assemblages from three calcareous tufa deposits in the Luberon mountain were used to reconstruct Lateglacial and Holocene palaeoenvironments. The Lateglacial communities only differ from the Pleniglacial ones by the development of hygrophilic snails. We note a high moisture budget at the end of the Lateglacial Interstadial (LGI). A patchy, steppe landscape is attested. A time lag in recolonization by woodland species during the LGI is conceivable. The postglacial woodland assemblages then trace a laborious reassembly of forest snail communities. It takes place mainly between c. 8000 and c. 6600 cal. a BP with spatial disparities and delayed recruitments. The French Mediterranean region has not benefitted from the macrorefugia that it would have sheltered or with which it would have been close. Woodlands, however, appear progressively more closed and complex c. 8000 cal. a BP. They reached their optimum c. 7500 to 7400 cal. a BP although their canopy seems to have stayed quite open. Anthropization remained weak during the Early Neolithic. A significant woodland opening is observed in the Early–Middle Neolithic. Human impact becomes clear from the Late Neolithic. Nevertheless, there are substantial differences compared with Basse‐Provence, where a more marked openness of the landscape from 7000 cal. a BP was accompanied by the development of Mediterranean synanthropic snails. The molluscan successions of the Luberon mountain should be a reference for the development of the Lateglacial and Holocene malacofauna in the SE of France, at the northern boundary of the western Mediterranean domain.

Clocks at a snail pace: biological rhythms in terrestrial gastropods.

Biological rhythms are ubiquitous across the tree of life. Organisms must allocate their activities into moments of the day and of the season that will increase their probability of surviving and reproducing, which is done in the form of daily and annual rhythms. So far, the vast majority of studies on biological rhythms have focused on classical laboratory model species. Still, the use of non-model species is gaining traction, as part of an effort to achieve a more holistic understanding of clock/calendar mechanisms in the "real world" but this requires species that can be studied in both the lab and in nature. Terrestrial gastropods, i.e., land snails and slugs, have the potential to be exciting models for the study of biological rhythms in nature. Therefore, we provide a review of the research on biological rhythms in terrestrial gastropods, with a focus on ecology and evolution. We present the state of the art in the field while giving a historical perspective of the studies, exploring each of the main lineages of terrestrial gastropods. We also point out some interesting directions that future studies could take to fill some of the more urgent gaps in current knowledge. We hope that our contribution will renew interest in this area and spark novel projects.

Not Blown away: Over Three-Quarters of Species in a Pacific Atoll Land Snail Assemblage Remain Five Years Post-Typhoon

Not Blown away: Over Three-Quarters of Species in a Pacific Atoll Land Snail Assemblage Remain Five Years Post-Typhoon

Not Blown away: Over Three-Quarters of Species in a Pacific Atoll Land Snail Assemblage Remain Five Years Post-Typhoon

Not Blown away: Over Three-Quarters of Species in a Pacific Atoll Land Snail Assemblage Remain Five Years Post-Typhoon

Shell morphology and reproductive anatomy of Levantina mardinensis (Gastropoda, Helicidae) from a new locality of Mardin, Türkiye

ABSTRACT The genus Levantina Kobelt, 1871, comprises 25 taxa inhabiting rocky environments across the Middle East. This study focuses on documenting a new location of L. mardinensis Kobelt, 1900, and provides a detailed analysis of its shell morphology and reproductive anatomy, contributing to the knowledge and conservation of this land snail from Mardin, southeastern Türkiye. The distribution of L. mardinensis is widespread in Mardin Province and extends into northern Syria and Iraq. The study provides measurements for previously unreported shell characteristics of specimens from Eskikale (Mardin), including aperture height, aperture width, spire height, and body whorl height, with high-resolution images for visual reference.

Three new species of Camaena Albers, 1850 (Gastropoda, Stylommatophora, Camaenidae) from Guizhou and Guangxi, China

AbstractThree new species of camaenid land snail, Camaena qiannanensis Chen, Dai, Wu & Ouyang sp. n., Camaena feichenyui Chen, Dai, Wu & Ouyang sp. n. and Camaena qinghuai Chen, Dai, Wu & Ouyang sp. n. are described from Guizhou and Guangxi of southern China based on shell and genital morphology, and molecular phylogeny. The phylogenetic result shows that the genus Camaena is not a monophyletic group, with Camaenella located within it. The discovery enhances the species diversity of Camaena in Southern China and fills the gap between distribution areas of known species.

Vertigo andrusiana Pilsbry, 1899, not “Vertigo columbiana Sterki, 1892”, nomen nudum (Gastropoda: Vertiginidae)

The correct name for a common, temperate north-western North American land snail is discussed. In a 2018 revision of the genus Vertigo O.F. Müller, 1773, “Vertigo columbiana Sterki, 1892” was used for this species by its authors, who synonymised V. andrusiana Pilsbry, 1899 with it. However, V. columbiana Sterki, 1892 is a nomen nudum and, as this name is not made available until a publication in 1900 by Pilsbry and Vanatta, the earliest available name is V. andrusiana.

Seasonal variation in the biochemical composition of the albumen gland of the giant African land snail Archachatina marginata in Abeokuta, Ogun State, Nigeria

ABSTRACT Archachatina marginata is an African pulmonate gastropod widely reared for food. There is a lack of information on the influence of seasonal changes on the reproductive physiology of these snails, hindering optimum reproduction throughout the year. Thus, the aim of this study was to measure seasonal variation in the albumen gland of A. marginata snails in Abeokuta, Ogun State, Nigeria. A total of 252 snails was purchased from the Department of Forestry and Wildlife Management of Federal University of Agriculture, Abeokuta, Ogun State, Nigeria. The snails were acclimatised for three weeks in rearing cages. Twenty-one snails were dissected each month for twelve months and the albumen gland separated. Samples collected were analysed in the laboratory using standard chemical methods. Data collected were analysed using one-way analysis of variance and t-test. Glucose (P < 0.05) and protein (non-significant) were found to be higher in the dry season than in the rainy season, while cholesterol (P < 0.05) and triacylglycerol (non-significant) were higher in the rainy season than in the dry. In conclusion, this study showed that the biochemical composition of the albumen gland of A. marginata snails was influenced by seasonal variation.

Speciation in the desert: A new endemic Iberus land snail restricted to the southeastern Iberian Peninsula

Arid habitats constitute harsh environments for hydrophilic animals such as land snails. Still, several land snail species appear to inhabit arid environments and such species present an array of adaptations needed to minimise water loss in dry habitats. However, different species may have found different solutions for the same problem. Here, we describe Iberus xerophilus sp. nov., a new species of arid-dwelling land snail from southeastern Spain, on the basis of phylogenetic analyses. Moreover, we show a detailed morphological description as well as a characterization of its habitat. A comparison with the shell morphology of other aridity resistant Iberus land snails casts the question of how this snail can succeed in such harsh arid environments. Southeastern Spain constitutes a hotspot for Iberus arid-dwelling species, displaying a plethora of shell morphologies. The description of this new species might contribute to our understanding of the evolution and diversification of land snails specifically adapted to drought and arid conditions.

Land snail Δ47 thermometry using cultured and European natural populations of Clausilia pumila, Succinella oblonga and Trochulus hispidus

Clumped isotope composition (Δ47) of aragonitic shells of terrestrial molluscs allow the quantitative reconstructions of continental paleotemperatures from loess-paleosol records of the last 2.5 million years, but it needs testing the method under controlled laboratory conditions and using natural populations. In this study the stable carbon, oxygen and clumped isotope compositions of cultured individuals and field-collected specimens of three species (Clausilia pumila, Succinella oblonga and Trochulus hispidus), widespread in Quaternary loess deposits in Europe, were measured in the Debrecen (ATOMKI) and ETH Zürich laboratories. Our data of cultured snails demonstrate that shells of the three species record Δ47 signatures close to equilibrium conditions with mostly positive (C. pumila), both positive/negative (T. hispidus), and mostly negative (S. oblonga) offsets on the order of 0.0158 ± 0.0105 ‰ (mean offset±1 SD) compared to the Anderson et al. (2021) unified calibration. Calcification temperatures (TΔ47) derived from C. pumila shells were found to be in excellent agreement with chamber temperatures of 12, 18 and 24 °C, especially in the ATOMKI laboratory (mean T offset: 2.1 ± 2.2 °C, 1 SD), while the other two species exhibited larger discrepancies on the order of 5–8 °C (mean offset). Single shell-based mean TΔ47 values of field-collected molluscs indicated growth temperatures spanning values from the frost-free period to summer season, or even above summer maxima. The sites of natural populations, characterized by different climate conditions, could be grouped using the aridity index (AI) with values of 0.96–1.06 representing mean temperature of the frost-free period (TFFP), and AI ranging either from 0.85 to 0.91 or 1.14 to 1.51 reflecting mean summer season or July temperatures (TJJA/TJ). Multi-shell TΔ47, obtained by homogenizing the material of 3–5 shells of C. pumila and T. hispidus, reflect TJJA in most cases. We observed a dependence of the shell oxygen isotope compositions of the three species on oceanity/continentality with more negative/positive values characteristic for more continental/oceanic sites, likely due to moisture source distance and depletion of rainfall in 18O towards the continental interior. In addition, deviation of body fluid δ18O values (derived from δ18Oshell and Δ47shell) from seasonal precipitation δ18O is also controlled by an additional temperature effect, being independent of the climate zone of the collection site, but co-varying with the site-specific difference between single shell TΔ47 and TJJA.

A new species of Lysinoe (Gastropoda: Helicoidea) from the Oligocene of Mexico

In her 1945 study on the Tertiary fossil mollusks of northeastern Mexico, Gardner listed only 2 taxa of land snails: Holospira eva Gardner, 1945 and “Helix” sp. The latter is recognized here as a new species of Lysinoe Adams &amp; Adams, 1855 (Helicoidea, Xanthonychidae). The new species can be diagnosed from its congeners by its flattened shell profile, a lower body whorl with a faint angulation on its median portion, a ridge-like angulation around the umbilicus, and a likely wide umbilicus. The species is known to occur in 2 nearby Upper Middle Oligocene outcrops in the eastern part of the state of Nuevo León.

Comparative shell morphology of the rare land snails Levantina ninivita and Levantina escheriana (Gastropoda: Helicidae) in south-eastern Türkiye

Comparative shell morphology of the rare land snails Levantina ninivita and Levantina escheriana (Gastropoda: Helicidae) in south-eastern Türkiye

Mild histological distortions in rat organs after a 14-day oral exposure to the slime extract of African giant land snails

ObjectiveSnail slime possesses various pharmacological activities that are becoming attractive for zootherapy, thereby necessitating the profiling of its safety and toxicity. Therefore, using OECD 425 guidelines, this study assessed the acute toxicity of Archachatina marginata slime extract and performed a histological analysis of the vital organs. MethodsEighteen (18) Wistar rats were assigned randomly into three groups: control, 2000 mg/kg, and 5000 mg/kg bw slime extract. The dosing of the animals with 2000 mg/kg bw and 5000 mg/kg bw was done according to the limit test procedure, after which the animals were observed for 14 days. During the observation period, clinical and behavioral changes were recorded. The rats were euthanized after 14 days of monitoring, and their essential organs were excised for gross histological examination. ResultsThere was no mortality during the observation period, and the LD50 of A. marginata slime extract was determined to be greater than 5000 mg/kg bw. Although there were no behavioral alterations in the rats after oral exposure to the slime extract, the histological examination revealed mild cellular distortions in the rat organs. Furthermore, a preliminary chemical analysis of the slime extract revealed the presence of flavonoids and phenolics. ConclusionA. marginata slime extracts may be grouped as low toxic substance based on the results obtained (LD50 > 2000 – 5000 mg/kg). However, the histological distortions in rat organs following acute oral exposure to the snail slime extract not only warrant further, in-depth toxicological investigations but also caution in its use for traditional medicinal purposes.

Microplastics’ Impact on the Environment and the Challenging Selection of Reliable Key Biomonitors

Microplastics (MPs) persist for long periods in the environment, causing adverse effects on aquatic and terrestrial ecosystems. The accumulation of MPs in various trophic levels mostly depends on weathering phenomena, their reduced dimensions and the improved bioavailability; this ultimately causes their ingestion by organisms living in different niches. The modern concern about MPs toxicity collides with the current unavailability of standardized and reliable methodologies to assess the risks associated with the exposure of organisms from different habitats. Hence, the identification and selection of appropriate biomonitors for MPs pollution risk assessment should focus on the identification of easy-to-implement assays, rapidly interpretable results (e.g., based on the MPs bioaccumulation capabilities in their tissues) and standardizable methodologies. The present review analyzed some emerging biomonitors exploited for MPs evaluation, selected and examined according to their potential use as specific biological indicators for diverse environments. The research was focused on plants, as biological models for airborne microfibers toxicity evaluation; mussels, as key organisms for the establishment of MPs accumulation in marine environments; land snails, representing emerging organisms selected for studies of MPs’ impact on soil. Furthermore, recent findings evidenced the influence of microplastics on the composition of environmental microbiota, enhancing pathogenic biofilms formation, leading to increased water, soil, food, crops and waste contamination. Disposing of harmonized and validated methods to study MPs’ impact on the environment, integrated with promising machine learning tools, might sensibly support the risk management strategies protecting human and animal health.

LOCAL ECOLOGICAL KNOWLEDGE ON LAND SNAIL DIVERSITY IN MOUNT BANAHAW, PHILIPPINES

Local ecological knowledge (LEK) is a community-based conservation effort that promotes sustainable management of natural resources. However, studies on LEK are very limited in the Philippines. To address this information gap, LEK on land snails in Mount Banahaw, Luzon Island, Philippines was investigated. Key informant interviews and focus group discussions were conducted in the four communities (Dolores, Lucban, Tayabas and Majayjay) along the slope of the mountain. A snail calendar was used as a tool for identifying the hunting season and practices of these communities on land snails. The results showed that the communities were knowledgeable on macro land snails (&gt;5 mm shell size) such as the introduced species, Lissachatina fulica and the endemic and edible, Ryssota otaheitana, but were unaware of micro land snails ( 5 mm shell size). Locals also demonstrated an awareness of the snails’ ecosystem functions as a food source for other animals and agents of nutrient cycling. Additionally, sustainable hunting of R. otaheitana in communities was observed. Only adult R. otaheitana were harvested, leaving the juveniles to grow and reproduce. In Lucban, the people hunted while they were waiting for the harvest season of their crops. In Tayabas, the community observed that the snail was abundant during wet and moist soil conditions when leaf litter, its primary food, decomposed easily. In Majayjay, hunting was associated with the blooming of the flowering plant, Erythrina variegata. In Dolores, hunting was practiced after clearing farmland. This research underscores the importance of determining LEK in developing policies and regulations on sustainable utilization and conservation of land snails in a tropical forest setting.

High resolution stable isotope ratios in modern African land snails: Testing inferred environmental conditions

High-resolution sub-annual stable oxygen isotope data were measured in modern land snail shells collected from different climatic zones in Africa to search for patterns in seasonal δ18O cycles associated with specific hydroclimates, keyed to flora/biozones. Thirty-three recently dead shells were collected between 1995 and 2012, and collection localities were divided into five climate types: tropical forest, woodland savannah, bushland savannah, woodland monsoon, and arid/semi-arid. Thirteen genera are represented in the collection. Sampling covered at least one year in the life of the land snails, often multiple years. A comparison of measured data to predicted δ18O values, using local temperature and rain δ18O value, shows that predictions tend to be lower than measured values, suggesting that surface waters or snail body waters have undergone some evaporation. Predictions based on night-time temperatures (average monthly minimum T) are closer to, but still underestimate, measured values compared to day-time (maximum) temperatures in a majority of cases. The largest range in δ18O values for individual shells occurs in the bushland savannah and woodland monsoon biomes. Longer seasonal intervals of dry conditions lead to greater δ18O ranges in shells, although if the dry interval approaches 10 months in the year the amplitude is again reduced. This is in agreement with other oxygen isotope studies of high-resolution land snail shell samples, which show very high δ18O variance in strong monsoon climates.

Trade and socioeconomic importance of an invasive giant snail in the endemic-rich island of São Tomé, Central Africa.

Managing invasive species is crucial to mitigate their negative impacts on ecosystems, yet conflicts may arise when their social benefits are disregarded. Human pressure on the endemic-rich forests of São Tomé has been high since the island was discovered by the Portuguese in the 15th century, and numerous species have been introduced. These include the invasive West African giant land snail (Archachatina marginata), which was introduced in the mid-20th century, is now widespread on the island, and is a potential threat to native flora and fauna. We assessed the frequency of consumption of this species and its socioeconomic importance to people across the island with household questionnaires, focus group discussions, and semistructured interviews. We explored the prevalence and potential drivers of use (e.g., wealth, household composition, and diversity of occupations) and characterized the commodity chain to identify demographic groups linked to the snail trade. We interviewed 672 people (1 person per household), conducted 6 focus groups, and interviewed 80 key actors belonging to 5 subcategories. The snail was the most widely consumed bushmeat and an important source of income, particularly for women and unemployed youth. Insecure and scarce livelihood alternatives, mostly in rural areas, were reported as drivers for trade involvement. Snail harvesting was more frequent in poorer households with low occupational diversity. Selling tended to occur in households that were well-established in the community and had a higher proportion of children. Both were stimulated by the proximity of communities to the native forest. Buying snails was common in all demographic groups, but it was linked to wealth and occupational diversity. Interventions to manage the impact of this introduced species on the valuable ecosystems of the island should involve multiple sectors of society to ensure societal support. This requires robust consideration of the welfare of vulnerable demographic groups that benefit from the species.

The phylogeny and diversification of the western Eurasian Phaedusinae (Gastropoda: Stylommatophora: Clausiliidae)

Abstract The little-known western Eurasian taxa of the Phaedusinae (land snail family Clausiliidae) are Tertiary relicts, which are widely separated geographically from the rest of the subfamily occurring in eastern Eurasia. In order to elucidate the phylogenetic relationships of this group, we carried out molecular analyses with 11 of the 16 genera using nuclear gene sequences. Our results revealed that within the subfamily, Nothoserrulina and Pamphylica, together with Caspiophaedusa, Dobatia, Pravispira, and Serrulina, belong to a clade that is sister to that of all east Eurasian Phaedusinae except Synprosphyma. In contrast, Graecophaedusa, Laeviphaedusa, Pontophaedusella, and Serrulinella, together with Pontophaedusa, belong to paraphyletic lineages diverging between the branching point of these clades and that of the most basal Synprosphyma lineage. Laeviphaedusa and Pontophaedusella represent the earliest western Eurasian lineages, estimated to date back to the Eocene–Oligocene boundary. Comparison of our phylogeny to morphological traits of the genera identified clade-specific character states of the shells and the reproductive organs. Based on fossil records and on palaeogeographical and palaeofloristic data, we also propose a model for the geographical origin and radiation of this subfamily in Eurasia.

Preliminary Data on the Species Composition and Distribution of Land Snail (Mollusca: Gastropoda) in Son Doong Cave, Phongnha - Kebang National Park

Son Doong Cave it is the largest cave on the planet and also the most majestic cave in Vietnam. Son Doong Cave is divided into habitats: Dark cave (covered by the cave ceiling) and light cave (not covered by the cave ceiling), including doline 1 and doline 2.Surveying and collecting land snail samples in Son Doong cave was carried out in January 2023. For the first time, the list of terrestrial snail species in Son Doong Cave was published. This includes 30 species (11 phenotyps are just only identified to genus) belonging to 24 genera, 11 families, 3 orders, 3 subclasses; of which the presence of 5 species (Pincerna mouhoti, Leptopoma perlucidum, Scabrina patera, Chloritis khammouanensis, Amphidromus haematostoma) are newly recorded and added to the list of terrestrial gastropod fauna of Vietnam. In Son Doong cave, land snails are only distributed in the light part of the cave (Doline 1 and Doline 2), not in the dark part of the cave, which accounts for most of the cave area. Doline 2 has a higher species diversity (27 species belonging to 22 genera, 8 families, 2 orders) than Doline 1 (13 species belonging to 11 genera, 6 families, 3 orders). The diversity of land snail species in Son Doong cave is very unique and highly distinctive, but the species populations here is very small, requiring recommendations for tourists and the management board to protect vegetation to maintain and develop populations of this species.