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The superfamily Stromboidea is a clade of morphologically distinctive gastropods which include the iconic Strombidae, or 'true conchs'. In this study, we present the most taxonomically extensive phylogeny of the superfamily to date, using fossil calibrations to produce a chronogram and extant geographical distributions to reconstruct ancestral ranges. From these results, we confirm the monophyly of all stromboidean families; however, six genera are not monophyletic using current generic assignments (Strombidae: Lentigo, Canarium, Dolomena, Doxander; Xenophoridae: Onustus, Xenophora). Within Strombidae, analyses resolve an Indo‐West Pacific (IWP) clade sister to an East Pacific/Atlantic clade, together sister to a second, larger IWP clade. Our results also indicate two pulses of strombid diversification within the Miocene, and a Tethyan/IWP origin for Strombidae—both supported by the fossil record. However, conflicts between divergence time estimates and the fossil record warrant further exploration. Species delimitation analyses using the COI barcoding gene support several taxonomic changes. We synonymise Euprotomus aurora with Euprotomus bulla, Strombus alatus with Strombus pugilis, Dolomena abbotti with Dolomena labiosa, and Dolomena operosa with Dolomena vittata. We identified cryptic species complexes within Terebellum terebellum, Lambis lambis, "Canarium" wilsonorum, Dolomena turturella and Maculastrombus mutabilis. We reinstate Rimellopsis laurenti as a species (previously synonymised with R. powisii) and recognise Harpago chiragra rugosus and Lambis truncata sowerbyi valid at the rank of species. Finally, we establish several new combinations to render Lentigo, Dolomena, and Canarium monophyletic: Lentigo thersites, Dolomena robusta, Dolomena epidromis, Dolomena turturella, Dolomena taeniata, Dolomena vanikorensis, D. vittata, "Canarium" wilsonorum, Hawaiistrombus scalariformis, Maculastrombus mutabilis, Maculastrombus microurceus. [ABSTRACT FROM AUTHOR]

Neogastropoda is a large order of predominantly marine gastropod molluscs, typically predatory or parasitic on other animals. It includes over 16,000 species representing a large post‐Cretaceous radiation, but the internal phylogenetic relationships of contained taxa are far from resolved, with inconsistent results from nuclear genes, mitogenomes, and morphology. One major issue in reconstructing the molecular phylogeny is the lack of high‐quality sequences for early‐diverging families and superfamilies such as Volutidae (Volutoidea). Here, we examine the superfamily‐level phylogenetic relationships in Neogastropoda, aided by newly sequenced draft genome and mitogenome of the volutid snail Fulgoraria chinoi from the deep sea off Japan. The genome of F. chinoi is relatively large at 1.54 Gb but exhibits low genome heterozygosity; over 54% of this genome constitutes of repeat contents, and we find evidence for active insertion of transposable elements, particularly LINEs and SINEs. A total of 50,792 protein‐coding genes (PCGs) were predicted from the nuclear genome, and a circular mitogenome was also assembled and annotated. Our phylogenetic analyses using mitogenomes recovered each neogastropod superfamily as monophyletic, though also revealed inconsistent phylogenetic signals within superfamilies. Phylogenetic reconstructions using the PCGs resulted in a robust tree from different models and data matrices, recovering Volutoidea as the earliest diverging superfamily (among those for which comparable data is available) within a monophyletic Neogastropoda. Dated phylogenetic analysis revealed an early Cretaceous radiation of Neogastropoda, congruent with the fossil record. Our study provides a robust internal evolutionary framework for the speciose but genomically undersampled Neogastropoda, and expands the available genomic resources for this order. Genomic data for key missing lineages such as Mitroidea, Olivoidea, and Cancellariidae are much sought in the future for a full understanding of Neogastropoda evolution. [ABSTRACT FROM AUTHOR]

Based on specimens collected from the Yemeni shore of the Red Sea, Yemeninassoides inusitatus gen. & sp. nov. is here described and figured. The shell morphology suggests that this species belongs to the family Nassariidae Iredale, 1916. The new taxon is characterised by light shell, base finely spirally lyrate, open umbilicus and multispiral non-keeled protoconch sculptured by spiral cords and arcuate axial riblets. The combination of these morphological features is so far unique and makes the new taxon easily distinguishable from all other known species and genera in the family Nassariidae.https://zoobank.org/References/0E009334-D9C7-4CC7-9A06-466582E1F263 [ABSTRACT FROM AUTHOR]

The deep-sea raphitomid genus Gymnobela Verrill, 1884 (Neogastropoda: Conoidea) has historically been a container for a multitude of raphitomid species, assigned to this genus almost exclusively based on shell characters. Consequently, the genus has become taxonomically inflated. However, a 2021 molecular study redefined Gymnobela and taxonomically revised the genus. Herein, we present an integrative taxonomic study that, mainly based on samples from Australian waters, further defines this problematic genus, as well as the closely related genus Pontiothauma E.A. Smith, 1895. An automatic barcode gap discovery (ABGD) analysis of three mitochondrial genes resulted in six primary species hypotheses (four in Gymnobela and two in Pontiothauma). We recognised morpho-anatomical and bathymetric/geographical characters distinct to all six and found available names for four; we name one new species, Pontiothauma transregnasp. n., but abstain from naming one presumably unnamed Pontiothauma due to a lack of well-preserved adult specimen material. We provide clear synapomorphic characters unique to both Gymnobela and Pontiothauma, notably those of the radula. Furthermore, we present the first evidence supported by molecular data of a transoceanic distribution among the raphitomids, namely in Gymnobela angulosa Sysoev, 1988. Additionally, we recognise non-molecular evidence that might indicate similarly wide distributions in Gymnobela agasizzi (Verrill and Smith, 1880), Gymnobela engonia Verrill, 1884 and Gymnobela frielei Verrill, 1885. Consequently, and to avoid taxonomic splitting, we herein advocate for wide-ranging investigation of worldwide material when conducting taxonomic studies on deep-sea conoideans, due to growing evidence of transoceanic distributions in the group. Finally, through an exhaustive search of worldwide repositories and the literature, and in conjunction with our molecular, morpho-anatomical and bathymetric/geographical data, we have reassigned 16 species from Gymnobela to other genera within the family Raphitomidae. [ABSTRACT FROM AUTHOR]

The Babyloniidae is a family of marine snails consisting of 21 species and two genera. Current taxonomic debates on the Babyloniidae are mainly due to their extremely similar shell morphologies, which have led to incorrect locality records and mislabelling in legal or illegal international trade. We have therefore constructed a phylogeny of the Babyloniidae with high species coverage (57% of the family) by using multi‐locus genes (cytochrome c oxidase subunit I [COI], 16S, and H3) with four species delimitation methods (Best Close Match [BCM], Assemble Species by Automatic Partitioning [ASAP], Bayesian Poisson Tree Process [bPTP] and Multi‐rate Poisson Tree Processes [mPTP]). Based on our results, 13 clades/operational taxonomic unit were observed, which confirms pre‐existing species status for 10 Babylonia and one Zemiropsis taxa: B. areolata (Link, 1807), B. borneensis (Sowerby II, 1864), B. feicheni Shikama, 1973, B. formosae (Sowerby II, 1866), B. japonica (Reeve, 1842), B. lutosa (Lamarck, 1816), B. pieroangelai Cossignani, 2008, B. spirata (Linnaeus, 1758), B. valentiana (Swainson, 1822), B. zeylanica (Bruguière, 1789) and Z. papillaris (Sowerby I, 1825). A monophyletic group with four species collected from Indonesia which includes B. spirata f. balinensis Cossignani, 2009, B. spirata f. semipicta (Sowerby II, 1866) and B. angusta Altena & Gittenberger, 1981, implying they should belong to a single species, B. semipicta. Additionally, we suggest B. formosae habei Altena & Gittenberger, 1981 should be escalated as B. habei, and not as a subspecies. [ABSTRACT FROM AUTHOR]

Mud snails (family Nassariidae) represent a highly diversified lineage within the superfamily Buccinoidea. Recent molecular phylogenies contradicted in some instances the traditional nassariid classification and revealed important levels of homoplasy in phenotypic characters. In order to clarify the boundaries of the family Nassariidae, as well as to inquire on the diversification of the cosmopolitan Nassariinae, a robust phylogenetic framework is needed. Here, the near-complete mitogenomes of 31 species representing almost all lineages of Nassariidae plus several buccinoid outgroups were sequenced. All mitogenomes of buccinoids shared the same gene order, which is identical to the consensus reported for caenogastropods. The monophyly of Nassariidae as previously defined was not confirmed. The reconstructed phylogeny revealed distant relationships between the genera Cyllene, Anentome, Tomlinia, Engoniophos, Phos and Antillophos and the majority of nassariids, represented by Nassariinae + Bullia. Within Nassariinae, a robust phylogeny, which recognized a total of seven regional groups, was reconstructed. The West Atlantic/Mediterranean genus Tritia was divided into three clades. The biogeographical analysis together with the inferred chronogram suggested that Nassariinae might have originated during the late Paleocene in the Indo-Pacific region. Subsequent climate change and continental drift events triggered diversification within the subfamily, leading to the worldwide distribution of current genera. [ABSTRACT FROM AUTHOR]

The Cretaceous Period is characterised by a peak in ocean surface acidity, which may have altered the fossil representation of its marine biota. Thus, we propose to study the dissolution of Caenogastropoda shells and to verify the number of fossil occurrences of the respective families during the Cretaceous, aiming to produce insights on which groups present a higher chemical preservation potential in low pH environments. An experimental taphonomy approach was used to obtain the mass loss rate of 12 shells without taphonomic damage. Morphometric measurements were conducted, and each shell was subjected to a solution of acetic acid diluted in distilled water, remaining for 24 h. At each interval of four and eight hours, the samples were dried, weighed, and pH of each container was checked. As result, it was recognised that the samples with lower dissolution rates, in other words more resistant to the chemical conditions of the simulated benthic taphonomically active zone, are those that distribute the shell mass over a smaller surface area. This corroborates with the high occurrence of their respective families during the Cretaceous. The Caenogastropoda shells that show the highest chemical preservation potential, therefore, are those with the lowest surface area to mass ratio. [ABSTRACT FROM AUTHOR]

In this report we describe 32 species belonging to 26 genera of Caenogastropoda from the early Eocene Cambay Shale of the Cambay Basin, western India. This is the first report of gastropod fossils from this basin, and introduces 24 new species, 2 new subgenera and 3 new genera. The new genera, Eopreangeria, Indobatillaria and Pachycerithium, include new species Eopreangeria mangrolensis, Indobatillaria ismatae and Pachycerithium richardi. The new subgenera are Lyrispina in the genus Lyria and Carinotoma in the genus Apiotoma, including new species Apiotoma (Carinotoma) rammohani. The remaining new species are: Amaurellina cambayensis, Ampullina vastanensis, Amp.? eocenica, Ptychocerithium shamukum, Bittium purnimae, Bi. kamalae, Pseudobellardia sitae, Serratocerithium indicum, Potamides mosaliensis, Pot. shahensis, Sandbergeria khanae, Benthonella prosoclinata, Teinostoma maryae, Natica naroliensis, Involuta? ishwari, Rimella rokeyae, Siphonalia kalpanae, Si. pritilatae, Strepsidura reticulata and Amalda bibhae. A palaeoenvironmental analysis and the diversity–abundance pattern of this fossil fauna provide evidence of an overall marginal marine environment that experienced the Ypresian marine transgression and a gradual increase in marine influence. [ABSTRACT FROM AUTHOR]

Venomous marine gastropods of the superfamily Conoidea possess a rich arsenal of toxins, including neuroactive toxins. Venom adaptations might have played a fundamental role in the radiation of conoideans; nevertheless, there is still no knowledge about the venom of the most diversified family of the group: Raphitomidae Bellardi, 1875. In this study, transcriptomes were produced from the carcase, salivary glands, and proximal and distal venom ducts of the northeastern Atlantic species Raphitoma purpurea (Montagu, 1803). Using a gut barcoding approach, we were also able to report, for the first time, molecular evidence of a vermivorous diet for the genus. Transcriptomic analyses revealed over a hundred putative venom components (PVC), including 69 neurotoxins. Twenty novel toxin families, including some with high levels of expansion, were discovered. No significant difference was observed between the distal and proximal venom duct secretions. Peptides related to cone snail toxins (Cerm06, Pgam02, and turritoxin) and other venom-related proteins (disulfide isomerase and elevenin) were retrieved from the salivary glands. These salivary venom components may constitute ancestral adaptations for venom production in conoideans. Although often neglected, salivary gland secretions are of extreme importance for understanding the evolutionary history of conoidean venom. [ABSTRACT FROM AUTHOR]

Fulgoraria rupestris is a predatory marine gastropod belonging to Neogastropoda and possessing considerable taxonomic significance. However, research on this species remains limited. We acquired the complete mitochondrial genome of F. rupestris through second-generation sequencing and conducted an analysis of its genome structural features. The mitochondrial genome of F. rupestris spans a total length of 16,223 bp and encompasses 37 genes (13 protein-coding genes (PCGs), 22 transfer RNAs, and 2 ribosomal RNAs). Notably, most tRNAs exhibit the typical cloverleaf structure, but there is an absence of the Dihydrouridine (DHU) arm in the trnS1 and trnS2 genes. The A + T content is 68.67%, indicating a pronounced AT bias. Additionally, we conducted a selection pressure analysis on the mitochondrial genomes of four species within Volutidae, revealing that all PCGs are subjected to purifying selection. In comparison to other species within Neogastropoda, F. rupestris shares an identical gene arrangement. Additionally, based on mitochondrial genome sequences of the 13 PCGs from 50 species within Neogastropoda, we constructed a phylogenetic tree. The phylogenetic tree indicates F. rupestris forms a clade with species within the family Volutidae (Cymbium olla, Neptuneopsis gilchristi, and Melo melo). This study serves as a valuable reference for future research on F. rupestris, offering insights for the upcoming phylogenetic and taxonomic classification within Neogastropoda. Furthermore, the findings provide valuable information for the development of genetic resources in this context. [ABSTRACT FROM AUTHOR]

In 2022, the accepted name for a marine gastropod species from Florida until then known as Conus anabathrum Crosse, 1865, was replaced by C. floridanus Gabb, 1869. The main argument was that the type of C. anabathrum , a specimen with no type locality in the description, actually represents the eastern Pacific species C. scalaris Valenciennes, 1832. This allocation of the type of C. anabathrum to an eastern Pacific taxon was based on several factors, with shell shape as the main determinant. We demonstrate via geometric morphometrics that the type of C. anabathrum actually falls outside the morphospace of C. scalaris , belonging instead to the morphospace of the Floridian taxon. We also discuss other arguments presented to assign the type of C. anabathrum to the eastern Pacific species. These discussions and our geometric morphometric analytical results demonstrate that the type of C. anabathrum actually represents the Floridian species, and that C. anabathrum should be the accepted name. [ABSTRACT FROM AUTHOR]

Multilocus phylogenies have shown that soft-part anatomy alone is insufficient for the systematics of valvatiform- and trochiform-shelled springsnails of the subfamily Islamiinae (family Hydrobiidae) due to morphological similarities between taxa that are not closely related. However, a solid knowledge of their systematics and species boundaries is crucial to conserve this highly imperilled group. Here, we inferred molecular phylogenies based on two mitochondrial and two nuclear gene fragments from representatives of three morphological species of the Iberian genus Iberhoratia and performed multispecies coalescent and shell variation analyses (geometric morphometrics) to reevaluate their taxonomic status. The resulting phylogenetic analyses, which included homologous sequences of 15 other valvatiform-shelled hydrobiid species endemic to the Iberian Peninsula, depicted the topotypical specimens of I. aurorae and I. gatoa elisai distantly related to one another and the type species I. morenoi. Considering their high genetic divergence and morphological differences from other hydrobiid taxa, we have placed the former two species in the new genera Beatrix n. gen. and Actenidia n. gen. The multispecies coalescent delimitation method DELINEATE, a novel approach to the taxonomy of the Hydrobiidae, and shell morphometric data suggested two species within the 'I. gatoa elisai' clade. Based on morphological and molecular evidence, we recognized this clade as Actenidia , a new genus comprising the species A. elisai n. gen. n. comb. and A. baetica n. gen. n. sp. Our results underscore the importance of using multiple lines of evidence to delimitate species of Islamiinae and interpret their systematics. We also discuss the implications of our findings for conserving I. gatoa. [ABSTRACT FROM AUTHOR]

A fauna expedition has been conducted in Padang Bindu Karst, South Sumatra in 2021. Among the collected samples, a total of 111 specimens of Opisthostoma platycephalum (Caenogastropoda: Diplommatinidae) were collected from six sampling plots. This discovery is the first record of the land snail species in the southern of Sumatra island, as previous research only recognized its presence in Aceh, North Sumatra, and Peninsular Malaysia. This discovery contributes to the understanding of the biodiversity of South Sumatran land snails and highlights the importance of protecting limestone habitats. [ABSTRACT FROM AUTHOR]

The giant triton snail, Charonia tritonis (Linnaeus, 1758), crucial for coral reef ecosystems as a primary predator of the crown-of-thorns sea star, is experiencing a significant decline due to overfishing for its ornamental shell, underscoring the urgent need for conservation and deeper understanding of its role within marine biodiversity. This study presents the first complete mitogenome sequence of C. tritonis. Spanning 15,346 bp, the C. tritonis mitogenome comprises 13 protein-coding genes (PCGs), 22 tRNA genes, and two rRNA genes. Phylogenetic analysis of 88 Littorinimorpha mitogenomes confirms C. tritonis and C. lampas are grouped together within the family Charoniidae as a sister group to the remaining Tonnoidea families. This research not only enhances the taxonomic classification and conservation efforts for marine gastropods but also serves as a vital reference for future evolutionary and genetic studies within the Caenogastropoda. [ABSTRACT FROM AUTHOR]

The molluskan order Neogastropoda encompasses over 15,000 almost exclusively marine species playing important roles in benthic communities and in the economies of coastal countries. Neogastropoda underwent intensive cladogenesis in the early stages of diversification, generating a "bush" at the base of their evolutionary tree, which has been hard to resolve even with high throughput molecular data. In the present study to resolve the bush, we use a variety of phylogenetic inference methods and a comprehensive exon capture dataset of 1817 loci (79.6% data occupancy) comprising 112 taxa of 48 out of 60 Neogastropoda families. Our results show consistent topologies and high support in all analyses at (super)family level, supporting monophyly of Muricoidea, Mitroidea, Conoidea, and, with some reservations, Olivoidea and Buccinoidea. Volutoidea and Turbinelloidea as currently circumscribed are clearly paraphyletic. Despite our analyses consistently resolving most backbone nodes, 3 prove problematic: First, the uncertain placement of Cancellariidae, as the sister group to either a Ficoidea-Tonnoidea clade or to the rest of Neogastropoda, leaves monophyly of Neogastropoda unresolved. Second, relationships are contradictory at the base of the major "core Neogastropoda" grouping. Third, coalescence-based analyses reject monophyly of the Buccinoidea in relation to Vasidae. We analyzed phylogenetic signal of targeted loci in relation to potential biases, and we propose the most probable resolutions in the latter 2 recalcitrant nodes. The uncertain placement of Cancellariidae may be explained by orthology violations due to differential paralog loss shortly after the whole genome duplication, which should be resolved with a curated set of longer loci. [ABSTRACT FROM AUTHOR]

Parasites exhibit high diversity in various ecosystems. Habitat selection has played an important role in the diversification of parasites by facilitating intra-host speciation and repeated shifts to a single host species by multiple parasite taxa. In this study, we investigated habitat selection in two gastropod species, Melanella cf. acicula and Peasistilifer nitidula (Caenogastropoda: Vanikoroidea: Eulimidae), that are parasitic on the black sea cucumber Holothuria atra in southwestern Japan. The number and position of parasites were observed for 335 hosts; in total, 89 individuals of M. cf. acicula and 194 of P. nitidula were found. Melanella cf. acicula exhibited strong habitat selection, with 70 individuals (78.7%) attached around the host's mouth, whereas P. nitidula had relatively low infection site specificity. This suggests that the two parasite species have different feeding habits. Molecular phylogenetic analysis verified their non-monophyletic relationship, indicating that they likely made independent host shifts to H. atra. The observed difference in habitat preference, as well as the abundance of suitable habitats, may have contributed to the repeated host shifts and sympatric distribution of M. cf. acicula and P. nitidula. Our phylogenetic analysis also revealed the non-monophyly of eulimids parasitising holothuroids, as in asteroid and ophiuroid parasitic taxa. [ABSTRACT FROM AUTHOR]

The fifth mass extinction event (MEE) at the Cretaceous–Palaeogene (K–Pg) boundary 66 million years ago (Ma) led to massive species loss but also triggered the diversification of higher taxa. Five models have been proposed depending on whether this diversification occurred before, during or after the K–Pg boundary and the rate of species accumulation. While the effects of the K–Pg MEE on vertebrate evolution are relatively well understood, the impact on invertebrates, particularly in freshwater ecosystems, remains controversial. One example is the hyperdiverse Hydrobiidae—the most species‐rich family of freshwater gastropods. Whereas some studies place its origin in the Jurassic or even Carboniferous, most fossil records postdate the K–Pg event. We therefore used robustly time‐calibrated multi‐locus phylogenies of >400 species representing >100 hydrobiid genera to unravel its evolutionary history and patterns of diversification. We found that the family started diversifying shortly after the K–Pg boundary (∼60 Ma; 95% highest posterior density 52–69 Ma). Lineage richness gradually increased to the present and phylogenetic diversity until ∼25 Ma. These findings suggest that diversification was not initially driven by ecological opportunity. Combining the two criteria of timing and rate of diversification, a soft‐explosive diversification model of aquatic vertebrates best fits the patterns observed. We also show that most higher hydrobiid taxa (i.e. subfamilies) diversified from the Middle Oligocene to Middle Miocene (i.e. 12–28 Ma). Two of the 15 major clades delimited are described here as new subfamilies (i.e. Bullaregiinae n. subfam. and Pontobelgrandiellinae n. subfam.), whose members are restricted to subterranean waters. Our results are an important contribution to understanding how the fifth MEE has shaped evolution and patterns of biodiversity in continental aquatic systems. Given the high extinction risks faced by many hydrobiids today, they also emphasise the need to study the biodiversity of vulnerable ecosystems. [ABSTRACT FROM AUTHOR]

Simple Summary: Lophiotoma leucotropis belongs to the Turridae and is a carnivorous snail that is widely distributed in shallow sea sand and intertidal zones around the world. Currently, the mitochondrial genome sequence of L. leucotropis has not been explored. And there is also great controversy over whether the order Neogastropoda to which L. leucotropis belongs is monophyletic. We sequenced the mitogenome of L. leucotropis and analyzed its basic gene characteristics. We found that it contains a total of 37 gene contents. Similar to species in the Turridae family, it has a higher content of AT bases and a preference for some codons. The selection pressure analysis results showed purification selection effects, and through comparison with other species in Turridae, it was found that the gene sequence of this species is conserved, which helps to deepen the understanding of the Turridae. We constructed a phylogenetic tree using the 13 protein coding genes of Neogastropoda and concluded that the order is monophyletic. This result is a supplement and validation to the research on the evolutionary status of Neogastropoda and also provides reference for the species classification and germplasm resource development of Neogastropoda. Neogastropoda is a group of marine organisms with an extremely wide distribution that is rich in species and economic and ornamental values, the classification of species in this order has been ongoing for a long time, but there is still a great controversy about whether this order is monophyletic. In this study, we obtained the complete mitogenome of Lophiotoma leucotropis by next-generation sequencing and analyzed the basic structural features of the genome, and we found that the number of genes was consistent with that of most of the Neogastropoda snails, containing 37 genes, including 13 protein-coding genes (PCGs), 2 rRNAs, and 22 tRNAs. Analyzing base content, amino acid content, codon usage preference, and tRNA structure, the mitogenomes of eight species of Turridae were selected for analysis of selection pressures, and it was found that the evolution of species in this family was affected by purifying selection. In addition, by analyzing the rearrangement characteristics, it was found that the sequence of L. leucotropis was consistent with the Conoidea consensus order, and four of the eight species involved in the analysis showed rearrangements. Finally, we constructed a phylogenetic tree by combining PCGs of 60 species within Caenogastropoda and found Neogastropoda to be a monophyletic group, validating the results of morphological classification. The results will provide more references for the classification and species evolution of Neogastropoda, as well as phylogenetic analysis. [ABSTRACT FROM AUTHOR]

Based both on published GenBank DNA sequences and newly produced sequences, I have assembled the largest multi‐loci sequence dataset of the Diplommatinidae to date to investigate their evolutionary history. The focus of this study is on the diverse genus Palaina, which is represented by new sequences of its type species as well as additional samples from Timor and the Solomon Islands. In addition, the type species of Palmatina from Norfolk Island is also included. A relaxed molecular clock hypothesis is presented that incorporates several calibration points based on fossils or on previously published age estimates for major clades. Accordingly, the Sundaland diplommatinids Plectostoma, Opisthostoma, Arinia and Diplommatina are of considerable evolutionary antiquity, each likely having originated during the Cretaceous or early Paleogene at the latest. The Palaina sensu lato main clade was found to be the sister of all other diplommatinids included in the tree and has also diverged during the late Cretaceous. Palaina as currently delineated is rendered non‐monophyletic by the radiations of Hungerfordia and Eupalaina, which are endemic to the archipelago of Palau, as well as Palmatina from Norfolk Island. [ABSTRACT FROM AUTHOR]

Among gastropods, the ability to swim has developed independently several times, mostly among Heterobranchia. Only a few species of Caenogastropoda are known to have swimming adults. Velutinidae Gray, 1840, is a family of caenogastropods with a fragile shell enclosed by the mantle. The adults of this family are benthic and ectoparasites of ascidians. Here, we present the first recorded instance of a swimming velutinid, Marsenia cf. gemma, filmed in New Caledonia. The swim propulsion method was based on the movement of the snail's foot, which followed a ∞-shaped curve. This first report changes our perspective on the biology of this family, unexpectedly placing it within the restricted group of swimming caenogastropods. [ABSTRACT FROM AUTHOR]

Alviniconcha marisindica Okutani 2014 is a deep-sea gastropod inhabited in hydrothermal vents of the Indo-Pacific. It belongs to superfamily Abyssochrysoidea. In the present study, we report the complete mitochondrial genome of A. marisindica, which is 15,979 bp in length and contains 13 protein-coding genes, 2 rRNA genes, 22 tRNA genes. The nucleotide composition is 29.19% of A, 38.22% of T, 16.88% of G, and 15.71% of C. The phylogenetic analysis indicates that A. marisindica and A. boucheti clustered in the Abyssochrysoidea clade with high bootstrap support. The mitochondrial genome of A. marisindica provides valuable molecular data for further research on the evolution of deep-sea gastropods. [ABSTRACT FROM AUTHOR]

Previously, the main studies were focused on viruses that cause disease in commercial and farmed shellfish and cause damage to food enterprises (for example, Ostreavirusostreidmalaco1, Aurivirus haliotidmalaco1 and Aquabirnavirus tellinae). Advances in high-throughput sequencing technologies have extended the studies to natural populations of mollusks (and other invertebrates) as unexplored niches of viral diversity and possible sources of emerging diseases. These studies have revealed a huge diversity of mostly previously unknown viruses and filled gaps in the evolutionary history of viruses. In the present study, we estimated the viral diversity in samples of the Baikal endemic gastropod Benedictia baicalensis using metatranscriptomic analysis (total RNA-sequencing); we were able to identify a wide variety of RNA-containing viruses in four samples (pools) of mollusks collected at three stations of Lake Baikal. Most of the identified viral genomes (scaffolds) had only distant similarities to known viruses or (in most cases) to metagenome-assembled viral genomes from various natural samples (mollusks, crustaceans, insects and others) mainly from freshwater ecosystems. We were able to identify viruses similar to those previously identified in mollusks (in particular to the picornaviruses Biomphalaria virus 1 and Biomphalaria virus 3 from the freshwater gastropods); it is possible that picorna-like viruses (as well as a number of other identified viruses) are pathogenic for Baikal gastropods. Our results also suggested that Baikal mollusks, like other species, may bioaccumulate or serve as a reservoir for numerous viruses that infect a variety of organisms (including vertebrates). [ABSTRACT FROM AUTHOR]

The occurrence of Ocinebrellus inornatus and Rapana venosa, two exotic marine gastropods of the family Muricidae originating from the northwest Pacific, is reported in Spanish waters, specifically in the Galician waters (NW Spain) in 2023. Live specimens of O. inornatus were found on Illa de Arousa, in the Ría de Arousa, southern Galicia, where they are already established. Two new specimens of R. venosa are recorded in Galicia, one of them for the first time out of the Ría de Arousa, representing a range expansion for the species. The DNA barcoding analysis confirms the previous morphological identifications. It is suspected that both species may have been introduced through importation of clam spat and middle-sized oysters from countries such as France, the United Kingdom or Italy for subsequent culture, as has been the case with other exotic species that can currently be found in Galician waters. The continuous arrival of marine exotic species strongly supports the need to establish a monitoring program in Galician waters. [ABSTRACT FROM AUTHOR]

The larvae of the marine gastropod Lophocochlias parvissimus are meroplankton that spend part of their lives as plankton that disperse and drift in the water column before settling on the sea floor. Two individuals of L. parvissimus larvae were sampled by the Multiple Opening/Closing Net and Environmental Sensing System (MOCNESS) from the Central Indian Ridge of the southwestern Indian Ocean in 2018 and 2019. We generated the first mitochondrial sequences for L. parvissimus, which will provide valuable genetic insight into the evolution of these organisms. In this study, we have determined that the mitogenome of L. parvissimus was 13,575 bp in length, consisting of 13 protein-coding genes, 18 tRNAs, and two rRNAs. Our work provides a new insight into the dispersal of L. parvissimus and previously missing components to the general understanding of the evolution of Truncatelloidea (Subclass Caenogastropoda). [ABSTRACT FROM AUTHOR]

Simple Summary: We sequenced the complete mitochondrial genomes of nine Tonnoidean species, and analyzed the genomic features including genome size, gene order, nucleotide composition and Ka/Ks ratio. The reconstructed phylogeny based on mitogenomic data supported the Tonnoidea classifications at family levels, but their internal relationships remained unclear. At the species level, the present study indicates that species diversity within Bursidae might be underestimated. The Tonnoidea Suter, 1913 (1825) is a moderately diverse group of large predatory gastropods, the systematics of which remain unclear. In the present study, the complete mitochondrial genomes of nine Tonnoidean species were sequenced. All newly sequenced mitogenomes contain 13 protein-coding genes (PCGs), 22 transfer RNA genes and two ribosomal RNA genes, showing similar patterns in genome size, gene order and nucleotide composition. The ratio of nonsynonymous to synonymous of PCGs indicated that NADH complex genes of Tonnoideans were experiencing a more relaxed purifying selection compared with the COX genes. The reconstructed phylogeny based on the combined amino acid sequences of 13 protein-coding genes and the nucleotide sequences of two rRNA genes supported that Ficidae Meek, 1864 (1840) is a sister to Tonnoidea. The monophylies of all Tonnoidean families were recovered and the internal phylogenetic relationships were consistent with the current classification. The phylogeny also revealed that Tutufa rebuta (Linnaeus, 1758) is composed of at least two different species, indicating that the species diversity within Bursidae Thiele, 1925 might be underestimated. The present study contributes to the understanding of the Tonnoidean systematics, and it could provide important information for the revision of Tonnoidean systematics in the future. [ABSTRACT FROM AUTHOR]

The Western Balkans hosts the richest subterranean aquatic gastropod fauna in the world. The main factors shaping intraspecies diversity are thought to be isolation and endemism. In the genus Belgrandiella, minute snails inhabiting subterranean waters and springs in Central Europe and Balkans, molecular studies have shown much fewer valid species than previously anticipated. The present study applies mitochondrial cytochrome c oxidase subunit I, histone 3, and RAPD analysis, to check the inter- and intraspecies genetic diversity in 36 Belgrandiella populations from caves, springs and interstitial aquifers. The level of gene flow is assessed to check if these snails form a widespread genetically uniform metapopulation or rather follow the highly endemic pattern. The studied populations have been assigned to six species. In the most widely distributed B. kusceri from 21 populations, 60 sequenced specimens represent 16 haplotypes. While the same haplotypes are present in distant populations, gene flow between the other populations is low. Nei distances for RAPD show no geographic pattern. The interspecies differences in COI evidently confirm the time of speciation in Pleistocene, before karstification, which rejects speciation within isolated caves. The pattern observed in Belgrandiella seems more similar to the one described in Montenegrospeum than in Kerkia. [ABSTRACT FROM AUTHOR]

Cycloryx pemaledai Gittenberger et Sherub, 2022, which was described from northwestern Bhutan, is reported for the first time in Sikkim, India. That species differs from all its congeners by the short R3 (the region between the constriction and the peristome). The differences between the Bhutanese and Indian shells are minimal, therefore the Indian shells are identified as Cycloryx cf. pemaledai. Furthermore, Alycaeus himalayae sp. n. is described from Arunachal Pradesh. This is so far the only Alycaeus species inhabiting the Himalayas, and thus, its discovery is a surprise. [ABSTRACT FROM AUTHOR]

The terrestrial gastropod Ferussina petofiana Páll-Gergely sp. n. is described from uppermost Cretaceous (Maastrichtian) deposits from the Haţeg Basin, Romania. It represents the first properly diagnosed and described snail taxon from these deposits, despite numerous earlier reports of gastropod occurrences. This new species is characterized by a depressed, mostly smooth shell, three spiral carinae on the ventral side (inside the umbilicus), and an upward-turning aperture. The last feature characterizes two European fossil snail genera, the cyclophoroidean Ferussina, and the stylommatophoran Strophostomella. The new species is classified in the former group due to its nearly circular aperture, and the presence of conspicuous spiral carinae. In contrast, the aperture of most stylommatophoran genera (including Strophostomella) is semilunar, and if raised sculptural elements are present, they are mostly radially oriented. The identification of this new taxon in the uppermost Cretaceous of Romania represents an important range extension for the genus Ferussina, and adds it to the brief list of European clades that appear to have survived the mass extinction event at the Cretaceous-Paleogene boundary. [ABSTRACT FROM AUTHOR]

The Edwards and Edwards-Trinity Aquifers of Texas have diverse stygofauna, including fifteen species of snails found in phreatic and hyporheic habitats. These species have the hallmarks of adaptation to subterranean environments including extremely small body size and the loss of pigmentation and eyes. Here we use an integrative taxonomic approach, using shell, radula, and anatomical features as well as mitochondrial and nuclear DNA data, to circumscribe a new genus and two new cavesnail species from Central Texas. Vitropyrgus lillianae gen. et sp. nov. is described from Comal Springs (Comal County) and Fessenden Springs (Kerr County) and distinguished by a glassy, highly sculptured shell and distinctively simple, unornamented penial morphology. We also describe Phreatodrobia bulla sp. nov. from Hidden Springs (Bell County), and several other springs in Bell & Williamson Counties, Texas. This species has a smooth, unsculptured teleoconch, a reflected and flared lip, and deeply concave operculum. [ABSTRACT FROM AUTHOR]

The status of the indigenous Southeast Asian apple snails belonging to the genus Pila is of concern due to their fast rate of population decline, possibly as a result of multiple factors including habitat loss or disturbance and the introduction of globally-invasive apple snails, Pomacea spp. Conservation actions, including captive breeding of the native Pila species, have been suggested as urgent remedial practices, but the lack of knowledge regarding the fundamental reproductive biology of indigenous Pila spp. makes such practices difficult. In the present study, observations on the mating and egg-laying behaviour of an economic valuable apple snail native to Southeast Asia, P. virescens, were conducted using video recording to examine and describe their reproductive behaviour under a laboratory condition. A total of 15 types of mating and seven egg-laying behaviour were recorded. The mating sequence which subsequently resulted in egg laying was comprised of seven types of major sequential behaviour: mate probing, mounting, shell circling, positioning, insemination posture, sheath withdrawal and dismounting. Rejection of mating attempts by the female was frequently observed. Egg laying occurred during either day or night. A sequence of seven distinct types of behaviour were performed during oviposition: climbing, positioning, forming a temporary tube, mucous secreting, egg depositing, leaving and resting. Overall, these results provide an understanding of the egg-laying behavioural process and highlight its complexity in P. virescens. In addition, detailed ethograms of mating and egg-laying behaviour were derived. These will promote further systematic comparative studies of the reproductive behaviour of apple snails. [ABSTRACT FROM AUTHOR]

The gastropod Pachyoliva columellaris (formerly Olivella columellaris) is particularly common on many sandy beaches in North Peru. In the studied region north of Paita, Piura province, the species reaches densities of over 80,000 individuals per beach meter. The snails perform tidal migrations throughout the lunar cycle although tidal amplitudes differ four-fold between neap and spring tide. Not all animals complete their tidal migrations, and significant numbers remain above the water line at low tide. Throughout the tidal cycle, the proportion of small individuals is increased near the water line whereas large animals dominate in lower beach zones. I conclude that the sandy beaches north of Paita are well-suited for further studies of P. columellaris and the mechanisms underlying tidal migrations in invertebrates. [ABSTRACT FROM AUTHOR]

Apple snails of the genus Pomacea Perry, 1810 (Mollusca: Caenogastropoda: Ampullariidae) are native to the Neotropics and exhibit high species diversity, holding cultural and ecological significance as an important protein source in Peru. However, most genetic studies in Pomacea have focused mostly on invasive species, especially in Southeast Asia, where they are considered important pests. In this study, we assembled and annotated the mitochondrial genomes of two Pomacea species native to the Peruvian Amazon: Pomacea reevei Ampuero & Ramírez, 2023 and Pomacea aulanieri (Deville & Hupé, 1850). The mitogenomes of P. reevei and P. aulanieri comprise 15,660 and 16,096 bp, respectively, and contain the typical 37 genes of the animal mitochondria with a large control region of 292 bp in P. reevei and 524 bp in P. aulanieri—which fall within the range of what is currently known in Pomacea. Comparisons with previously published mitogenomes in Pomacea revealed differences in the overlapping of adjacent genes, the size of certain protein-coding genes (PCGs) and the secondary structure of some tRNAs that are consistent with the phylogenetic relationships between these species. These findings provide valuable insights into the systematics and genomics of the genus Pomacea. [ABSTRACT FROM AUTHOR]

Target‐capture approaches have facilitated a rapid growth in the field of phylogenomics but few probe sets exist for molluscs, an exceptionally rich phylum with unparalleled ecological and morphological diversity. We designed and tested the first universal probe set using Phyluce to capture ultraconserved elements (UCEs) and exon loci from the Subclass Caenogastropoda ‐ one of six major lineages of gastropods. The probe set consists of 29,441 probes designed to target 1142 UCE loci and 1933 exon loci (3075 total). In silico analyses of our probe set yielded an average of 2110 loci from genomes and 1389 loci from transcriptomes of diverse caenogastropods, from which an average of 1669 and 849 loci were retained respectively after screening to remove those that matched multiple contigs. Phylogenetic analyses of the loci extracted from transcriptomes produced well‐supported trees very similar to those published based on transcriptomic analyses. Phylogenetic relationships estimated from loci extracted from genomes recover similar phylogenetic relationships, and indicate that the loci targeted with this probe set are informative for resolving deep phylogenetic relationships. An in vitro analysis of the probe set with the Epitoniidae, a diverse caenogastropod family of uncertain affinity and with poorly resolved evolutionary relationships, recovered a total of 2850 loci. Although preliminary, the analysis of loci captured by our probe set for a small number of epitoniid taxa produced a well‐resolved tree indicating that this probe set is also able to resolve relationships at shallower hierarchical scales. Together, the in silico and in vitro analyses indicate that target‐capture enrichment with this probe set is a useful tool for reconstructing phylogenetic relationships across taxonomic levels and evolutionary time scales. [ABSTRACT FROM AUTHOR]

In desert environments, unique communities depend on groundwater from springs, including a diverse radiation of small (<5 mm) snails found in the desert across the southwestern United States. Nearly all springsnail species are considered critically imperiled with their existence depending on maintenance of spring-flows in regions of declining water availability. Extant, endemic springsnails in the Trans-Pecos region of Texas include one species of Pseudotryonia Hershler, 2001, five nominal Tryonia W. Stimpson, 1865 (Cochliopidae) and seven Pyrgulopsis Call & Pilsbry, 1886 (Hydrobiidae). Four of these are classified as endangered under the US Endangered Species Act. Surveys for springsnails were conducted at 128 sites, including 13 sites that were previously reported localities, and 115 previously unsampled spring sites were also searched for new springsnail populations. Sequences of the DNA barcoding region were used to establish a database of known sequences from the named species and confirm identifications of new populations encountered. We report eight new springsnail populations, including new records for T. metcalfi Hershler, Liu & Landye, 2011, T. cheatumi (Pilsbry, 1935), P. ignota Hershler, Liu & Lang, 2010, P. metcalfi (D.W. Taylor, 1987), and P. texana (Pilsbry, 1935). We were not able to recollect Juturnia brunei (D. W. Taylor, 1987), T. oasiensis Hershler, Liu & Landye, 2011, or P. davisi (D. W. Taylor, 1987). The DNA barcoding gap for Tryonia ranged from 1.56-4.47% and for Pyrgulopsis from 0.68-1.68%. [ABSTRACT FROM AUTHOR]

Muricidae is one of the most species‐rich and morphologically diverse families in Gastropoda, with a worldwide distribution. The classification of Muricidae has traditionally been based on shell and radular characteristics; however, the phylogenetic relationships within the family are debated due to morphological convergence and plasticity. In this study, to explore the phylogenetic relationships of Muricidae, we sequenced 11 muricid mitochondrial (mt) genomes and compared them with 13 previously reported complete muricid mt genomes. All muricid mt genomes shared the same gene arrangement and exhibited conserved genome size and nucleotide composition. Three‐nucleotide deletions in atp8 and nad4, and three‐nucleotide insertions in nad2 were detected in Rapaninae. Both maximum likelihood and Bayesian inference analyses supported the monophyly of each subfamily studied (Ocenebrinae, Muricinae, Rapaninae and Ergalataxinae). Ergalataxinae was recovered as the sister taxon of Rapaninae, refuting the traditional morphology‐based placement of Ergalataxinae within Rapaninae. In Rapaninae, Indothais was confirmed to be monophyletic and determined to be a valid genus. Similarly, Drupina was determined to be an independent genus rather than a subgenus of Drupa. Purpura was recovered as a paraphyletic group, with Purpura panama being sister to Reishia + Rapana + Indothais and clustering with Purpura bufo. [ABSTRACT FROM AUTHOR]

Microphytobenthos (MPB), typically comprised mainly of diatoms, is a key contributor to nearshore energy flow and nutrient cycles. Deposit‐feeding invertebrates are known to alter the structure and activity of MPB. The eastern mud snail Ilyanassa obsoleta can reach extremely high densities in estuaries of the northwestern Atlantic, and their deposit‐feeding and locomotion strongly influence other invertebrates and microbes. Our objective was to explore quantitative and qualitative effects of this keystone deposit‐feeder on diatoms of intertidal sediments. We gathered snails from mudflat and sandflat habitats and collected their fresh fecal pellets in the laboratory. DNA metabarcoding allowed us to characterize diatom assemblages of ingested sediments and feces. We noted selective feeding such that reduction in MPB biomass with gut passage was difficult to quantify. Diatom α‐diversity was reduced with gut passage in snails from both sedimentary regimes. Mudflat and sandflat diatom assemblages were distinct and differed markedly between feces and sediment in mud‐feeding snails, whereas the difference in sand‐feeding snails was minor. The sandy habitat was dominated by a mix of epipelic and epipsammic diatoms. In contrast, mudflat samples were dominated by epipelic and planktonic diatoms. Compositional differences between sediment and feces reflected preferential removal of planktonic taxa. Our results suggest the importance of phytodetritus to the mud snail diet, particularly in hydrodynamically quiescent environments. Due to the natural spatial patchiness of the snails and the capacity for rapid microbial recolonization, field experiments are recommended to determine whether MPB community changes attributed to gut passage are manifested at the landscape scale. [ABSTRACT FROM AUTHOR]

The systematics and distribution of the family Pupinidae (Gastropoda: Cyclophoroidea) in Java is reviewed. The family is represented in Java by four species of the genus Pupina, P. bipalatalis, P. compacta, P. junghuhni, and P. treubi. The shells of the species are described and figured, and the distribution data of the species are summarized. We have synonymized Pupina verbeeki Möllendorff, 1897 with Pupina treubi Boettger, 1890. All of the species except P. treubi, which is also known from Sumatra, are endemic to Java. Most previous records of Pupina from Java were from the western part of the island. Our new records show that the Pupina species are also more widespread in the drier central and eastern parts of Java. Their conservation status is therefore Least Concern. [ABSTRACT FROM AUTHOR]

Cone snails, as a type of marine organism, have rich species diversity. Traditionally, classifications of cone snails were based mostly on radula, shell, and anatomical characters. Because of these phenotypic features' high population variability and propensity for local adaptation and convergence, identifying species can be difficult and occasionally inaccurate. In addition, mitochondrial genomes contain high phylogenetic information, so complete mitogenomes have been increasingly employed for inferring molecular phylogeny. To enrich the mitogenomic database of cone snails (Caenogastropoda: Conidae), mitogenomes of four Conus species, i.e., C. imperialis (15,505 bp), C. literatus (15,569 bp), C. virgo (15,594 bp), and C. marmoreus (15,579 bp), were characterized and compared. All 4 of these mitogenomes included 13 protein-coding genes, 2 ribosomal RNA genes, 22 tRNA genes, and non-coding regions. All the Protein Codon Genes (PCGs) of both newly sequenced mitogenomes used TAA or TAG as a terminal codon. Most PCGs used conventional start codon ATG, but an alternative initiation codon GTG was detected in a gene (NADH dehydrogenase subunit 4 (nad4)) of C. imperialis. In addition, the phylogenetic relationships were reconstructed among 20 Conus species on the basis of PCGs, COX1, and the complete mitogenome using both Bayesian Inference (BI) and Maximum Likelihood (ML). The phylogenetic results supported that C. litteratus, C. quercinus, and C. virgo were clustered together as a sister group (PP = 1, BS = 99), but they did not support the phylogenetic relation of C. imperialis and C. tribblei (PP = 0.79, BS = 50). In addition, our study established that PCGs and complete mitogenome are the two useful markers for phylogenetic inference of Conus species. These results enriched the data of the cone snail's mitochondrion in the South China Sea and provided a reliable basis for the interpretation of the phylogenetic relationship of the cone snail based on the mitochondrial genome. [ABSTRACT FROM AUTHOR]

We analyse the distribution of the potamidid genus Terebralia Swainson, 1840 in the European fossil record (middle Eocene to Miocene). Extant Terebralia contains species restricted to mangroves and mudflats, rendering it a reliable element for detecting these coastal environments in the fossil record. Our contribution summarizes the European fossil record of this taxon and highlights the presence of this genus within coastal environments in the European realm. Distribution in the Cenozoic is interpreted based on ecological preferences, dispersal modes and climatic restrictions of recent species. Maximum geographical distribution is reached during the Early and Middle Miocene with two species being present from the southernmost parts of Europe and Anatolia to the North Sea Basin and the Paratethys. During the Late Miocene, the distribution of Terebralia lignitarum (Eichwald, 1830) is patchy and limited to the South of Europe. The Messinian Salinity Crisis coupled with a changing climate caused the disappearance of Terebralia in the Mediterranean first, and then marked the end of mangrove environments in this province. [ABSTRACT FROM AUTHOR]

This work presents information about 19 taxa recorded from different habitats at depths between 0.2 and 508 m in the last two decades, which are new records or poorly known species along the Turkish coasts. Among the identified species, Epitonium vaillanti, Melanella cf. lubrica, Melanella monterosatoi, Pelseneeria minor, Setia amabilis, Kurtziella serga, Rissoella diaphana, Rissoella inflata, and Spirolaxis clenchi are new records for the Turkish mollusc fauna, Eatonina pumila is new report for the Turkish coast of the Aegean Sea, and Eatonina ochroleuca, Acirsa subdecussata, Lamellaria latens, Setia pulcherrima, Setia valvatoides, and Turbonilla cangeyrani are species with rare distribution which were sampled for one or a few times only. Viriola cf. bayani, Acirsa subdecussata, Melanella monterosatoi, Eatonina ochroleuca, E. pumila, Setia amabilis, Setia pulcherrima, Lamellaria latens, Rissoella diaphana, R. inflata, and Syrnola sp. were encountered along the Aegean Sea coast, whereas Epitonium vaillanti, Pelseneeria minor, Rissoidae sp., Kurtziella serga, Turbonilla cangeyrani, and Spirolaxis clenchi were recorded on the Levantine coast of Turkey, and Melanella cf. lubrica in the prebosphoric region of the Sea of Marmara. Setia valvatoides is the only species found on the Turkish Black Sea coast. On the other hand, Epitonium vaillanti and Viriola cf. bayani are species originated outside the Mediterranean basin. Most of the species were found at infralittoral and circalittoral depths, except for Kurtziella serga and Spirolaxis clenchi found at a depth of 508 m. The present study elucidates some ecological and distinguishing characteristics of the investigated species, along with their colour photographs and distribution along the Turkish coasts. [ABSTRACT FROM AUTHOR]

The superfamily Buccinoidea is the most speciose group of Neogastropoda within the Antarctic Convergence, with ~70 species classified in 21 genera, but is still poorly represented in molecular phylogenies. The first molecular data on the group presented in the recent phylogeny of the Buccinoidea (Kantor et al. 2022) lacked many important lineages, thereby limiting inference of the relationships of Antarctic Buccinoidea. We revisited relationships of the Antarctic Buccinoidea, involving recently collected molecular-grade samples from the bathyal and abyssal depths of the Scotia Sea, the Weddel Sea and adjacent regions. Our data set includes 25 species (including six genera studied on a molecular basis for the first time), sequenced for five phylogenetic markers: the barcode fragment of cox 1 gene, fragments of ribosomal 12S , 16S rRNA and 28S and nuclear H3 genes. Based on phylogenetic reconstructions, we synonymise the genus Lussitromina with Falsitromina and reassign the latter from Cominellidae to Prosiphonidae. We confirm the placement of four further genera, Drepanodontus , Germonea , Parabuccinum and Spikebuccinum in Prosiphonidae. We detect a previously unrecognised deep lineage of the family Prosiphonidae and describe this as the new genus Scotiabuccinum. The genus Parabuccinum , previously recorded in the Magellanic province and off the eastern coast of Argentina was reported for the first time within the Antarctic Convergence. We discover four previously unrecognised species of Antarctic Prosiphonidae and these are the first Buccinoidea from Antarctic waters described based on molecular data. According to our data, all but two species of Antarctic Buccinoidea belong to the family Prosiphonidae. Seven of the nineteen Recent Antarctic Prosiphonidae genera (36%) cross the boundaries of the Convergence and eight Antarctic genera are monotypic (42%). Currently no Buccinoidea species are known to occur both within and outside the Antarctic Convergence. ZooBank: urn:lsid:zoobank.org:pub:DEEA1599-C951-414E-9098-563EAD10BD57 The superfamily Buccinoidea is the most speciose group of Neogastropoda within the Antarctic Convergence with ~70 species classified in 21 genera. We revisited the relationships of the Antarctic Buccinoidea based on published molecular phylogeny and recently collected samples. In total, 25 species attributed to 17 (out of 21) genera were sequenced for five phylogenetic markers. We synonymised the genus Lussitromina with Falsitromina and reassigned the latter to Prosiphonidae. The new genus Scotiabuccinum and four new species are described. Parabuccinum is reported within the Antarctic Convergence for the first time. All but two species of Antarctic Buccinoidea belong to Prosiphonidae. No Buccinoidea species are known to occur both within and outside the Convergence. [ABSTRACT FROM AUTHOR]

The benthic macrofauna of Arctic and subarctic seas is mainly represented by widespread species and is generally devoid of endemics. The exceptions are reduced habitats, such as cold seeps, hydrothermal areas, and wood falls, which include endemics of at least the species level. A detailed study and analysis of such endemics allows us to understand the mechanisms of colonization and to assess the age of the fauna of high-latitude marine regions. Here, the new species Provanna annae sp. nov. is described from the geothermal zone of the Piip volcano in the Bering Sea (subarctic Pacific) based on the morphological and molecular phylogenetic data. The new species appears to be the northernmost and one of the most shallow-water species among the known representatives of the family and is suggested to be endemic to the region. The new species is related to a group of Provanna species from reducing habitats off Japan. Composition of the gut content indicates that the new species bottom sediments. Bacteria are found on the gills of the mollusc and are probably symbionts that also provide nutrition. This type of mixotrophic feeding is rare in gastropods and may be a unique feature among Caenogastropoda. [ABSTRACT FROM AUTHOR]

The gastropod radula is highly diverse in structure in comparison with that of other mollusсs. The main radular types in the different phylogenetic groups of gastropods differ not only in the general morphology and configuration of the teeth but also in the mode of tooth synthesis and the ultrastructure of the formation zone. Previously, the formation and anlage of the radula in the ontogeny of radulae of all major phylogenetic gastropods groups have been studied, with the exception of the taenioglossan radula of Caenogastropoda. The data obtained in this study on the radular anlage and synthesis in one littorinimorph species Lacuna pallidula supplement the existing knowledge of diversity in gastropod radula formation. The radula is initially formed at the stage of the post-torsion veliger, with five teeth in each transverse row, and acquires the adult morphology before hatching from the egg mass. The larval radula is synthesized by a few morphologically uniform cells in the radular sac. Synthesis of the adult radula also occurs at the blind end of the radular sac, where groups of numerous odontoblasts each form one tooth, and membranoblasts, located on the ventral side, form the membrane. Characteristic features of the adult radular sac are an additional supporting cartilage-like structure at the radula curve in the middle of the radular sac, a well-defined proliferation zone in the zone of radula formation and the presence of an additional extracellular matrix around the teeth in the maturation zone. [ABSTRACT FROM AUTHOR]

Neogastropoda is a group of marine organisms with an extremely wide distribution that is rich in species and economic and ornamental values, the classification of species in this order has been ongoing for a long time, but there is still a great controversy about whether this order is monophyletic. In this study, we obtained the complete mitogenome of Lophiotoma leucotropis by next-generation sequencing and analyzed the basic structural features of the genome, and we found that the number of genes was consistent with that of most of the Neogastropoda snails, containing 37 genes, including 13 protein-coding genes (PCGs), 2 rRNAs, and 22 tRNAs. Analyzing base content, amino acid content, codon usage preference, and tRNA structure, the mitogenomes of eight species of Turridae were selected for analysis of selection pressures, and it was found that the evolution of species in this family was affected by purifying selection. In addition, by analyzing the rearrangement characteristics, it was found that the sequence of L. leucotropis was consistent with the Conoidea consensus order, and four of the eight species involved in the analysis showed rearrangements. Finally, we constructed a phylogenetic tree by combining PCGs of 60 species within Caenogastropoda and found Neogastropoda to be a monophyletic group, validating the results of morphological classification. The results will provide more references for the classification and species evolution of Neogastropoda, as well as phylogenetic analysis.

The gastropod genus Litthabitella Boeters, 1970, type species L. chilodia Westerlund, 1886, inhabits mainly freshwater springs in the coastal regions of the Balkan Peninsula from Greece to Slovenia, southern Italy and the Ionian Islands. These snails are minute and show several synapomorphic character states, such as: broadly ovate osphradium, gonopore deep inside the mantle cavity, thickened circular oviduct, distal termination of the penis wide with a sharp and short lateral filament and two flat, cockscomb-like, four-folded lobes. These characters justify a family rank for the taxon. Three molecular loci – mitochondrial cytochrome oxidase subunit I, nuclear 18S and histone H3 – also confirm the distinctiveness of the Litthabitellidae fam. nov. Analysis of molecular data indicates an estimated time of origin in the Late Miocene (Tortonian) and supports its position as the sister clade of the Hydrobiidae. The shells, protoconchs, radulae, operculum, some histology, female reproductive organs and penis are herein illustrated and described. Molecular data presented for 10 studied populations, confirmed partly by morphological characters, indicate four distinct taxa of species rank. Three species are described: Litthabitella aquaadcrucem sp. nov., Litthabitella cetinensis sp. nov. and Litthabitella levkadensis sp. nov. [ABSTRACT FROM AUTHOR]

The snorkel snail genus Rhiostoma Benson, 1860 is comprised of terrestrial cyclophorid snails with wideranging species diversity and radiation in Southeast Asia. The typical characters of the genus are a depressed shell, a detached and descending portion of the last whorl with a distinctive peristomal breathing device attached, and a calcareous cup-shaped operculum. Herein, we have revised the systematics of extant species based on shell morphology combined with COI barcoding. From these thirty recognised species, twelve are described as new to science: R. ? amarapuraense sp. nov., R. anceyi sp. nov., R. breviocollar sp. nov., R. ebenozostera sp. nov., R. cheliopegma sp. nov., R. furfurosum sp. nov., R. gnomus, sp. nov., R. lannaense sp. nov., R. laoense sp. nov., R. platymorpha sp. nov., R. rhothonotaphrosa sp. nov., and R. tigrina sp. nov. All conchological characters are provided via illustrations of type specimens and living snails, and descriptions of the shells and radulae. Phylogenetic analysis based on partial COI gene sequences strongly supports the designated morphospecies and a monophyletic Rhiostoma, confirming that all pterocyclinid snails with a calcareous, cup-shaped operculum belong to the same clade. A high intra-specific divergence was observed in R. jalorensis and R. housei populations from locations in close proximity, suggesting a lower dispersal and higher level of isolation. The low inter-specific divergence found in R. hainesi, R. samuiense, R. asiphon, and R. rhothonotaphrosa sp. nov. supports their recent diversification and local adaptation, and is congruent with their marked morphological differences. Finally, nine formerly Rhiostoma-placed species were reclassified into either the genus Cyclotus or the genus Opisthoporus. [ABSTRACT FROM AUTHOR]

Anaglyphula yanseni, new species, is described and illustrated based on specimens collected from Babi Island, off the west coast of Sumatra, Indonesia. The new species mostly differs from its congeners having similarly pitted surface sculpture by its small size. Additionally, Anaglyphula cancellata Rensch, 1932, the type species of the genus, is redescribed based on the type materials. The diagnostic features of Anaglyphula are also discussed in comparison with those of similar genera. [ABSTRACT FROM AUTHOR]

Background Genomes are powerful resources to understand the evolutionary mechanisms underpinning the origin and diversification of the venoms of cone snails (Conidae: Caenogastropoda) and could aid in the development of novel drugs. Findings Here, we used PacBio continuous long reads and Omni-C data to assemble the chromosome-level genome of Kalloconus canariensis , a vermivorous cone endemic to the Canary Islands. The final genome size was 2.87 Gb, with a N50 of 79.75 Mb and 91% of the reads located into the 35 largest scaffolds. Up to 55.80% of the genome was annotated as repetitive regions, being class I of transposable elements (16.65%) predominant. The annotation estimated 34,287 gene models. Comparative analysis of this genome with the 2 cone snail genomes released to date (Dendroconus betulinus and Lautoconus ventricosus) revealed similar genome sizes and organization, although chromosome sizes tended to be shorter in K. canariensis. Phylogenetic relationships within subclass Caenogastropoda were recovered with strong statistical support. The family Conidae was recovered as a clade, with K. canariensis plus L. ventricosus sister to D. betulinus. Conclusions Despite the great diversity of cone snails (>900 species) and their venoms (hundreds of peptides per species), only 2 recently reported genomes are available for the group. The high-quality chromosome-level assembly of K. canariensis will be a valuable reference for studying the origin and evolution of conotoxin genes as well as whole-genome duplication events during gastropod evolution. [ABSTRACT FROM AUTHOR]