Search Results (148)

Holoplanktonic mollusks (Mollusca: Gastropoda: Pteropoda) are vital structural and functional components of marine zooplankton communities, characterized by high sensitivity to physicochemical shifts in the water column. Consequently, multidisciplinary assessments are essential to elucidate their community dynamics. This study investigated the epipelagic pteropod community structure in the deep-water basin of the southern Gulf of Mexico (sGoM) in relation to hydrographic features and circulation patterns. During the summer (September) of 2016, we collected high-resolution hydrographic data and zooplankton samples using CTD casts and oblique bongo net tows. Hydrographic data revealed intense temperature and density gradients, including a cold-dense core associated with a well-defined cyclonic eddy. The pteropod assemblage comprised 25 species from 13 genera and 10 families. Heliconoides inflatus (947.5 ind 100 m⁻³) and Limacina trochiformis (396.8 ind 100 m⁻³) were the most abundant species, whereas Cavolinia gibbosa (0.4 ind 100 m⁻³) and Cymbulia sp. (0.3 ind 100 m⁻³) were the least abundant. Horizontal distribution analyses revealed that the peak population densities occurred within the influence of the cyclonic eddy, particularly at its periphery where strong currents (>0.5 m/s) were recorded. A Canonical Correspondence Analysis identified temperature and salinity as the primary environmental drivers of community variability, while current systems significantly influenced the horizontal distribution of key species. Although pteropod research in the sGoM spans decades, most studies have been limited to taxonomic checklists, often overlooking environmental drivers and hydrographic influences. By applying a multidisciplinary approach to examine physical–biological coupling, this study advances the ecological understanding of this group within the historically underrepresented deep-water basin of the sGoM. Full article

This study provides the first updated checklist of Moroccan freshwater molluscs, synthesizing faunistic knowledge accumulated between 1795 and 2026. The dataset was primarily compiled from specialized literature, complemented by the authors’ expertise and recent field investigations. Taxonomic classifications at the family, genus, and species levels were revised in accordance with current systematic interpretations. In total, 106 freshwater molluscan species, belonging to 55 genera and 14 families, were documented. Chorological analysis reveals a clear dominance of Palearctic elements, particularly of Mediterranean affinity, alongside a high proportion of strictly endemic Moroccan taxa. Most of these endemics are associated with springs (crenobionts) and subterranean habitats (stygobionts), emphasizing the role of these environments as key centres of micro-endemism and diversification. A comprehensive database comprising 838 occurrence records was assembled, including GPS coordinates and sampling dates. The analysis identifies biodiversity hotspots mainly concentrated in the Mediterranean part of Morocco, particularly within the Middle Atlas Mountains, followed by the northeastern regions, where the highest species richness and citation rates were recorded. Despite this progress, significant gaps remain in the knowledge of Moroccan freshwater molluscs. Several regions still require further exploration, while ongoing threats—including pollution, habitat degradation driven by anthropogenic activities, global environmental change, and biological invasions—pose significant challenges. Addressing these gaps calls for intensified research efforts, including comprehensive field surveys, integrative taxonomic and molecular approaches, and long-term ecological monitoring. Overall, this study represents a significant step toward advancing the knowledge and conservation of freshwater molluscan diversity in Morocco. Full article

The current model of agricultural development, largely focused on the intensification of production, causes increased pressure on the natural environment and, at the same time, does not guarantee sufficient food supplies in the era of global demographic expansion. In light of current environmental changes and the escalating food shortage, the modern agricultural paradigm must strive to achieve a balance between productivity and the quality of agricultural products produced within an environmentally responsible production system. A promising and sustainable tool for future agriculture is a biorational model of agricultural production based, among other things, on the biological protection of agricultural products. The study aimed to assess the effectiveness of biological control agents containing entomopathogenic nematodes in controlling pests from the class Gastropoda. The tests showed that these preparations inhibited the feeding intensity of the analyzed pests. Among the insecticidal nematodes, the biological product containing S. carpocapsae at doses of 2000 and 4000 LJ/m² demonstrated the highest effectiveness (mass loss: A. distinctus: 0.61 g, 0.58 g; D. reticulatum: 0.60, 0.71 g). The research conducted indicates that preparations containing entomopathogenic nematodes have the potential to reduce damage caused by slugs in crops. Full article

This study examined the effects of several selected commercial detergents (cleaning cream, window cleaner liquid, lavender-scented dishwashing liquid, mint-scented dishwashing liquid, and pomegranate–verbena-scented dishwashing liquid) and the surfactant sodium dodecyl sulfate (SDS) on small aquatic invertebrates. The combined effects of these detergents with sodium chloride (NaCl) were also analysed. Acute toxicity tests were conducted on Chaoborus sp. larvae and Chironomus aprilinus Meigen larvae. These tests demonstrated that all tested substances were lethal to both taxa, although the effect on Chaoborus larvae was weaker. Tests involving sodium chloride combined with detergents yielded results similar to those obtained with detergents alone. LT₅₀ and 24 h LC₅₀ values were calculated. Chronic toxicity tests were conducted on meiobenthic assemblages sampled from two water bodies with contrasting ecological status: very good and eutrophic. Bray–Curtis faunal similarity analysis consistently separated control samples from detergent samples as a distinct cluster. The results indicated toxic effects at all tested dilutions and in samples from both water bodies. Among the observed taxa, Rotifera, Nematoda, Cladocera, Copepoda, Ostracoda, Insecta Diptera larvae, Insecta adult, Gastropoda, and Bivalvia, Ostracoda showed the greatest resistance to detergents, while Rotifera, Nematoda, Cladocera, and Copepoda demonstrated the highest sensitivity. A decrease in abundance and biodiversity was observed in all meiobenthic samples relative to the control samples. The results have a dual significance: 1. based on the obtained data, the developed procedures can be used as markers of detergent toxicity, and 2. in an economy based on sustainable development, commercial detergents should be considered as a serious source of surface water pollution affecting the ecological condition of water reservoirs and rivers. Detergents constitute a significant source of pollution and an obstacle to sustainable development in surface water protection. Full article

Although species identification is crucial for land-snail eggs, limited effort has been made to identify the species responsible for producing the eggs. In this study, we used laser ablation inductively coupled plasma mass spectrometry (LA–ICP–MS) to measure 54 elements in both the eggshells and adult shells of Bradybaena ravida and Cathaica fasciola and we used scanning electron microscope (SEM) to analyze the microstructure of the eggshells of the two species. Our results reveal that while the concentrations of Sr, Na, Mg, P, and Ba in the adult shells of the two species are not distinct, they are distinct or partially distinct between their eggshells, indicating that these elements have the potential to differentiate the eggs of the two species. Moreover, the eggshells of C. fasciola exhibit a blocky morphology without cavities, whereas those of B. ravida, while also blocky, contain irregular cavities. These distinct elemental and microstructural characteristics enable the effective differentiation of the eggs of B. ravida and C. fasciola. Our study demonstrates the feasibility of a critical microscopic methodology for identifying land-snail eggs at the genus/species level, thereby facilitating deeper exploration of their value in understanding biological, climatic, and ecological changes. Full article

Ustica is a Sicilian island for which most of the information available on the informal group of sea slugs comes from old and non-specific studies. Consequently, the aim of this study is to provide an updated list of the sea slugs of the Ustica Island Marine Protected Area (MPA). This study, carried out using the “photographic capture technique” in two surveys (early autumn and late spring), led to the finding of 32 species and 14 families of sea slugs. Overall, considering both the literature and current data, a total of 77 species and 33 families of sea slugs have been documented on this island. While these numbers might indicate high species richness compared to other previously investigated Sicilian islands, they might also reflect the fact that Ustica Island is the only one for which numerous malacological studies have been performed. Full article

A new intracellular parasite of the phylum Apicomplexa is described infecting the digestive gland of the gastropod Bulla striata from the south coast of Portugal. Only merogonial stages enclosed within parasitophorous vacuoles were observed by light and electron microscopy. The meront cytoplasm contained lipid droplets, rough endoplasmic reticulum cisternae, and several round or oval electron-dense microbodies closely associated with amylopectin granules, suggesting that these microbodies may represent glycosomes. Mitochondria or related organelles were not identified. A reticulum of branched tubules extending from the parasitophorous vacuole membrane was observed, likely increasing the surface available for metabolite exchange between parasite and host cell. Merozoites resulting from meront division were present within the parasitophorous vacuoles. They were elongated and slightly curved, measuring 7–8 µm in length and about 2 µm in width, and possessed an apical complex comprising numerous rod-shaped micronemes, rhoptries, and a conoid. Phylogenetic analyses based on a partial 18S rDNA sequence placed this parasite within the coccidian lineage, at the base of the ichthyocolid clade, a recently recognized group of apicomplexans previously known from fish blood cells. This finding expands the host range of ichthyocolids to gastropods and provides the first ultrastructural observations of this lineage, although only of merogonic stages. Full article

Understanding how geometry governs interfacial contact and material removal is central to designing efficient bioinspired surface systems. Gastropod radular teeth form natural arrays of microscale cutting elements optimized for repeated interaction with compliant and semi-rigid substrates, yet experimentally validated shape–performance relationships remain limited. Here, we isolate geometric effects on interfacial mechanics using stereolithography-printed biomimetic tooth arrays inspired by the taenioglossan radula of the hard-substrate grazer Spekia zonata. Two morphologically distinct tooth types (central and marginal) were systematically varied in cusp and stylus geometry (four variants each), while array configuration, material, and boundary conditions were kept constant. Tooth stiffness was quantified in bending tests as load-induced height reduction. Interfacial performance was assessed using a controlled pull-through assay in agarose substrates of two stiffness levels (0.4% and 0.8%), with continuous force recording and measurement of removed mass. Marginal-tooth geometries were stiffer and consistently removed more substrate than central variants. Although work increased substantially in stiffer gels, removal did not scale proportionally and declined for central teeth, revealing a decoupling between mechanical input and yield. Performance correlated with active engagement rather than work alone, indicating geometry-limited contact regimes. These findings establish geometry-controlled stiffness and engagement as key parameters for efficient abrasive interfaces. Full article

The identification of species complexes in freshwater snails remains challenging due to limited diagnostic morphological characters and incomplete taxonomic knowledge in many taxa. Within the family Bithyniidae, species have traditionally been classified using shell morphology and genital anatomy to distinguish intraspecific variation from interspecific differences. However, extensive morphological plasticity has hindered reliable species delimitation, and the presence of cryptic diversity further complicates taxonomy. Recent DNA barcoding studies of Hydrobioides have provided evidence of such cryptic diversity, highlighting the need for taxonomic reassessment within the genus. In the present study, we examined morphological variation in Hydrobioides nassa from Thailand in conjunction with mitochondrial DNA sequence data. Molecular phylogenetic analyses based on cytochrome c oxidase subunit I (cox1) sequences revealed three well-supported genetic lineages within H. nassa, accompanied by high levels of pairwise genetic divergence. Morphological comparisons of shell, operculum, and radular characters further supported differentiation among these lineages, although some characters showed overlap. While Hydrobioides has previously been regarded as comprising a single morphologically defined species, our results demonstrate that H. nassa represents a complex of genetically distinct lineages with subtle but consistent morphological differences. This study highlights the importance of integrating molecular approaches with traditional morphological analyses to improve taxonomic resolution and to better understand biodiversity within freshwater snail groups exhibiting cryptic diversity. Full article

Melanoides tuberculata is one of the world’s main invasive snail species; therefore, mapping its occurrence is essential for predicting its dispersion patterns and proposing control measures. This study aimed to map the occurrence of M. tuberculata and its associated parasites in a tourist waterfall complex located in Fortaleza dos Nogueiras, Southern Maranhão, Brazil. We collected snails over three months (July, August, and September 2025) in the Castanhão, Esmeralda, and Recanto das Águias waterfalls, and in the Panela stream, to estimate their reproductive stage and to assess the presence of parasites. We demonstrated for the first time the occurrence of M. tuberculata at all evaluated collection points. Morphological data of the shells suggested that the M. tuberculata populations were in the initial phase of their reproductive cycle; however, some specimens showed a complete reproductive stage. Additionally, we found M. tuberculata infected with trematode larvae that resembled the Gymnocephalus-type cercariae in the Castanhão waterfall and Panela stream. Therefore, we updated the distribution of M. tuberculata in Brazil and discussed the possible environmental and public health impacts of this species in the study area. Full article

Land snails have the highest recorded extinction rate, and these small animals are often overlooked, leading to data gaps. Past data for land snails is often lacking, making the analysis of trends difficult. Here, we compared past presence surveys to new quantitative estimates to infer changes over time. We surveyed 55 sites for land snails and habitat characteristics in 2024 using visual encounter surveys for medium to large snails and litter samples to assess the density of small to medium snails. We assessed habitat on two scales to assess associations and selection. We identified 27 land snail species, including a non-native species (Oxychilus cellarius). Sites with higher snail density and a richer assemblage generally had deeper litter, higher canopy cover and taller understory vegetation. Rare land snails were detected at most sites where they had previously been found, and we detected several species at new sites where they had not previously been documented, due to litter sampling. Vertigo arthuri (V. paradoxa) selected sites with a higher canopy cover. The abundance and density of land snails will enable better estimates of long-term trends and help assess how they respond to management actions. Resolving the taxonomy of Oreohelix and Succineidae is critical for direct management of these species. Full article

Some Sacoglossa sea slugs are capable of stealing and maintaining functional intracellular chloroplasts—kleptoplasts—from their macroalgal prey for periods of up to several months, a process known as kleptoplasty. Although the cultivation of these marine invertebrates under laboratory conditions is crucial for research in various fields (e.g., endosymbiosis, animal physiology, discovery of new marine natural products), rearing protocols are scarce. This study presents a standardized protocol for the laboratory rearing of large numbers of the sacoglossan tropical sea slug Elysia crispata. The detailed protocol successfully facilitated embryonic development, larval metamorphosis, and juvenile-to-adult transition, allowing the rearing of multiple generations. Two groups, characterized by acquiring different kleptoplasts, were obtained by feeding the sea slugs with two different prey macroalgae: Bryopsis sp. and Acetabularia acetabulum. Usually referred to as lettuce sea slug among marine aquarium hobbyists, E. crispata is a highly valued organism for its striking appearance and ability to control nuisance algal growth in reef aquariums. This protocol allows experimental reproducibility and access to specimens under different development stages, potentially boosting research on kleptoplasty while also contributing to reducing the impact of the marine aquarium trade on natural populations. Full article

Rivomarginella morrisoni (Gastropoda: Marginellidae) is a narrowly distributed freshwater snail inhabiting drainage basins of central and southern Thailand. To clarify patterns of genetic differentiation across its range, 45 individuals from 11 sites across eight river basins were analyzed using two dominant molecular markers: sequence-related amplified polymorphism (SRAP) and inter-simple sequence repeats (ISSR). SRAP primers produced higher polymorphic information content (PIC) values than ISSR primers (0.35 vs. 0.27). Analysis of molecular variance (AMOVA) revealed strong population structure, with 80.29% of the genetic variation occurring among populations and 19.71% within populations Population differentiation statistic (PhiPT) = 0.803, p < 0.001). Unweighted Pair Group Method with Arithmetic mean (UPGMA) and principal coordinate analysis (PCoA) consistently separated central and southern populations, and STRUCTURE supported K = 2 as the most likely number of clusters. Similarly, principal component analysis (PCA) of morphological traits also distinguished specimens into two groups corresponding to these geographic regions, confirming region-specific divergence. Overall, the genetic and morphological patterns indicate restricted gene flow among basins and a clear separation between central and southern lineages of R. morrisoni. This study provides the first molecular evidence of population structure in this species and offers important baseline information for future taxonomic, ecological, and conservation research on freshwater marginellid snails. Full article

Niclosamide has been the primary molluscicide for schistosomiasis control for over 50 years, but its chronic effects on inter-organ interactions in non-target mollusks remain poorly understood. Cipangopaludina cathayensis, a dominant species in East Asian schistosomiasis-endemic regions, was chronically exposed to environmentally relevant concentrations of niclosamide to assess its toxic effects. Digestive glands accumulated more niclosamide than the foot tissues. Prolonged exposure was associated with metabolic impairment of the digestive glands, characterized by tubular atrophy, inflammatory reactions, and depletion of nutrient components. Foot tissues exhibited epithelial lesions and muscle fiber atrophy. Alterations in foot structure were associated with changes in digestive gland nutrient status. Niclosamide exposure may weaken the metabolic coupling between these organs, thereby impairing locomotor function. At the population level, persistent niclosamide exposure may destabilize mollusk trophic-level populations, ultimately leading to ecological consequences. Our findings demonstrate the toxicological risks of niclosamide to freshwater mollusks. Full article

Caffeine (CAF), a prevalent psychoactive compound, has been identified as a significant environmental pollutant in freshwater ecosystems. This study investigates the behavioral and physiological effects of CAF at environmentally relevant concentrations (0, 5, 30, and 50 µg/L) on the freshwater snail Physella acuta, with a focus on both adult and embryonic responses. Adult snails were evaluated for alterations in speed, exploration, overall activity levels, and feeding behaviors, while embryos were assessed for heart rate and developmental changes. The study encompassed both short-term (24 h) and mid-term (7 days) exposure periods. Low CAF concentrations (5 and 30 µg/L) were found to enhance adult movement and exploratory behavior in the short term, whereas prolonged exposure resulted in a decline in these behaviors. A high CAF concentration (50 µg/L) consistently diminished movement and feeding in adults. Embryos exhibited a dose-dependent increase in heart rate and manifested malformations at elevated concentrations. These findings provide insights into the impact of CAF on freshwater invertebrates and contribute valuable data for ecological risk assessment. Full article