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Daphniola dionesp. nov., a valvatiform hydrobiid gastropod from Western Greece, is described based on conchological, anatomical and molecular data. D. dione is distinguished from the other species of the Greek endemic genus Daphniola by a unique combination of shell and soft body character states and by a 7–13% COI sequence divergence when compared to congeneric species. The only population of D. dione inhabits a cave spring on Lefkada Island, Ionian Sea.

This study reviews theDicharaxspecies in Thailand. Altogether tenDicharaxspecies are reported, four of which are new to science and described herein. They areDicharax borealisJirapatrasilp & Páll-Gergelysp. nov.,Dicharax burchiJirapatrasilp & Páll-Gergelysp. nov.,Dicharax panhaiJirapatrasilp & Páll-Gergelysp. nov.andDicharax pongratiJirapatrasilp & Tongkerdsp. nov.Alycaeus davisiGodwin-Austen, 1914 is regarded as a junior subjective synonym ofAlycaeus cucullatusTheobald, 1870 (=D. cucullatus) based on a similar depressed-conical shell shape, a long sutural tube and a sharp swelling behind the peristome. Furthermore, the type locality ofAlycaeus pratatensisPanha & Burch, 1997 (=D. pratatensis) had to be amended. Most important characters to distinguishDicharaxspecies are the general shell shape and relative lengths of teleoconch regions, whereas the spiral striation of R1, the shape of swelling of R3, the outer peristome crenulation and protrusion, and the exterior opercular sculpture show large intraspecific variability.

Members of the small bivalve family Cyrenoididae inhabit brackish waters of the eastern and western Atlantic Ocean. Cyrenoida floridana (Dall, 1896) from the western Atlantic is poorly known aside from shell descriptions. A detailed shell and anatomical study of C. floridana is here presented and compared with available data for Cyrenidae and Glauconomidae, two families of closest relationship according to recent phylogenetic studies. The species is characterized by valves externally covered by thin light brown periostracum; muscle scars and pallial line (without sinus) weakly impressed on the internal shell surface; a unique hinge pattern composed of cardinal and lateral teeth joining each other, right hinge with two laterals and two cardinals forming two inverted-V-shaped teeth and left hinge with two cardinals and one lateral forming a horizontal reversed F-shaped tooth; and microtubules inside the shell walls. Anatomically, the species presents unequal adductor muscles; demibranchs fused to each other along their posterior ends; a pair of totally fused, pigmented siphons; two pairs of siphonal retractor muscles; and a stomach with conjoined style sac and intestine, a single typhlosole, and three sorting areas. Evidence of shell parasitism is described.

Platydoris angustipes (Mörch, 1863) is a common nudibranch in the Western Atlantic, ranging from Florida, USA, to Rio de Janeiro, Brazil. In this study, we examined the anatomy of P. angustipes along its distribution, including its type material. Our analysis shows consistent differences between the Caribbean and Brazilian populations, mainly in the reproductive system, radular teeth and odontophore musculature. This strongly suggests that the two populations actually belong to distinct species. The Brazilian population is described herein as a new species, Platydoris guarani sp. n.

The Interior Highlands, in southern North America, possesses a distinct fauna with numerous endemic species. Many freshwater taxa from this area exhibit genetic structuring consistent with biogeography, but this notion has not been explored in freshwater snails. Using mitochondrial 16S DNA sequences and ISSRs, we aimed to examine genetic structuring in the Pyramid Elimia, Elimia potosiensis, at various geographic scales. On a broad scale, maximum likelihood and network analyses of 16S data revealed a high diversity of mitotypes lacking biogeographic patterns across the range of E. potosiensis. On smaller geographic scales, ISSRs revealed significant population structure, even over the distance of a few hundred meters. Unlike other freshwater mollusks like mussels, E. potosiensis showed no evolutionary patterns relating to biogeography. The species does show population-level genetic structure, which may have implications in conservation efforts.

Herein, we present a taxonomic revision of the genus Polygyratia Gray, 1847, with a new systematic placement in Scolodontidae and containing only the species Polygyratia polygyrata (Born, 1778). We offer an updated morphological description and geographical distribution, based on museum specimens and occurrence data gathered from literature and online database iNaturalist. We synonymise P. charybdis Mörch, 1852 with P. polygyrata. The species is known only from Atlantic Forest areas in Bahia state, eastern Brazil. We exclude three other species from the genus Polygyratia, classifying them as: Systrophia (Systrophia) heligmoida (d’Orbigny, 1835) and S. (Entodina) reyrei (Souverbie, 1858), based on conchological features; and S. (E.) pollodonta (d’Orbigny, 1835), though tentatively, based on scant published data. Finally, we present the first report of S. (S.) heligmoida (d’Orbigny, 1835) from Brazil.

A phylogenetic analysis using a combination of mitochondrial (COI, 16S) and nuclear markers (ITS2, 28S) indicated that Punctoidea, as previously interpreted, is polyphyletic. It comprises two main groups, containing northern hemisphere (Laurasian) and predominantly southern hemisphere (Gondwanan) taxa respectively, treated here as separate superfamilies. Within Punctoidea sensu stricto, Punctidae, Cystopeltidae and Endodontidae form separate monophyletic clades, but Charopidae, as currently interpreted, is paraphyletic. Most of the charopid taxa that we sequenced, including Charopa coma (Gray, 1843) and other Charopinae, grouped in a clade with Punctidae but some charopid taxa from Australia and South America grouped with Cystopeltidae. Cystopeltidae previously contained a single Australia-endemic genus, Cystopelta Tate, 1881, but our analysis suggests that it is considerably more diverse taxonomically and has a much wider distribution. For taxonomic stability, we suggest that Charopidae be retained as a family-level group for now, pending further study of the systematic relationships of its constituent taxa. A new superfamily, Discoidea, is erected here for two Northern Hemisphere families, Discidae and Oreohelicidae, which were previously assigned to Punctoidea. The North American species Radiodomus abietum, previously in Charopidae, is also here assigned to Discoidea. The phylogenetic relationships of Helicodiscidae, previously assigned to Punctoidea, were not fully resolved in our analysis, but the family is apparently closely related to Arionoidea Gray, 1840 and infraorder Limacoidei.

Asia contains a high species diversity of the freshwater gastropod genus Theodoxus. Recent molecular and morphological reviews of this diversity have uncovered a number of yet undescribed species while suggesting the urgent revision of several others. Moreover, some of these studies have indicated a number of species previously not recorded for this continent. Despite the advancements, a taxonomic revision and an update on the distribution of Theodoxus spp. in Asia is still pending. Here, we construct the most robust phylogeny of Theodoxus up to now and review original descriptions, type material, recent taxonomic revisions, compendia, and species lists to provide a comprehensive checklist of all known extant Asian Theodoxus spp. Our checklist also provides descriptions for three recently discovered and yet undescribed species (Theodoxus gurur Sands & Glöer, sp. nov., Theodoxus wesselinghi Sands & Glöer, sp. nov., and Theodoxus wilkei Sands & Glöer, sp. nov.), as well as shows the need to synonymise several previously described morphospecies. The present revision recognizes 14 extant Theodoxus spp. for Asia. Some of these species are widespread, while others are endemic to just a single location. Based on the revised and new distribution data, we provide updates and new assessments of species conservation statuses.

Malacological research in India has a long and productive history going back to the early 19th century, initially promoted by the Asiatic Society of Bengal and with significant material, including type material, deposited in the Indian Museum in Kolkata. Following the birth of the Zoological Survey of India (ZSI) in 1916, the Museum’s collecting activities and care for the collections themselves became the responsibility of the ZSI. The ZSI holds important collections of freshwater snails in the family Ampullariidae, including type material of taxa collected and described in the late 19th and early 20th centuries. This catalogue brings together information about these types, including for each taxon: bibliographic details of the original description, current taxonomic status, details of the type locality and type material, dimensions and illustrations of type specimens, and additional information as deemed necessary or interesting. The catalogue provides this information for 10 taxa, including four valid species and six junior synonyms. Two published names of subvarieties are listed but these are nomenclaturally unavailable. Lectotypes are designated for three taxa to stabilise the names.

The genus Habeastrum Simone, 2019 was recently described based on empty shells, counting with two troglobite species. Conchological features allowed a preliminary classification in the caenogastropod family Diplommatinidae, but this family allocation was left open to future studies. Herein, we present a detailed anatomical study of newly acquired specimens, confirming the classification in Diplommatinidae. These new specimens, from Minas Gerais state, SE Brazil, belong to a new troglobite species described herein, Habeastrum strangeisp. nov. The present records extend the genus distribution ca. 1,100 km east-northeast.

A new genus and a new species of Eulimidae are described based on the shell morphology and on the host-parasite relationship of the type species. Eulimacrostomamicrosculpturata Souza & Pimenta gen. nov. and sp. nov. parasitizes a starfish of the genus Luidia and has an elongated, conical, straight, or slightly curved shell, a protoconch with a brownish spiral band and convex whorls, a peculiar large and broad aperture with a strongly protruding outer lip, and microsculpture of axial lines on the teleoconch. Four other species are included in the genus, all from the western Atlantic: Eulimacrostomachascanon (Watson, 1883), comb. nov., Eulimacrostomafusus (Dall, 1889), comb. nov., Eulimacrostomalutescens (Simone, 2002), comb. nov., and Eulimacrostomapatula (Dall & Simpson, 1901), comb. nov. Newly available material of Eulimacrostomapatula expands the known geographic distribution of this species in the Caribbean to the north coast of Brazil. Eulimacrostomachascanon and Eulimacrostomafusus and Eulimacrostomalutescens are known only by the type series which was re-examined. A redescription is provided for Eulimacrostomachascanon and Eulimacrostomafusus. Species within Eulimacrostoma differ mainly by teleoconch sculpture, the presence or absence of an umbilical fissure, and shell dimensions. Lectotypes are designated for Eulimacrostomachascanon, Eulimacrostomafusus, and Eulimacrostomapatula.

The Eastern Mediterranean land snails Levantina display a disjunct distribution spanning the Middle East (Levant), Cyprus, few locations along the Aegean Turkish coast between Bodrum and Datça and on the islands of Rhodes, Karpathos and a few surrounding islets (Dodecanese). These land snails are strictly bound to limestone; shell variability is noticeable with a pair of umbilicate and non-umbilicate forms parapatrically distributed in the Levant and along the Aegean Turkish coast; they overlap on the Dodecanese islands. We sequenced fragments of two mitochondrial genes (Cytochrome Oxidase I and 16S rRNA) from the historical Levantina materials available at the Museums of Hamburg and Berlin. The aim of the study is to explain the current distribution of Levantina in the Eastern Mediterranean in light of an earlier hypothesis suggesting anthropochory due to the movements of Crusaders across the area. The deeper nodes in our phylogeny indicate that Levantina reached the Dodecanese from continental Turkey during the Pliocene exploiting continuity of landmasses. In five circumstances the same haplotype co-occurs on two different islands; one haplotype is shared between one island (Rhodes) and the Levant. We suggest that the movements of Crusaders likely explain the current distribution of haplotypes. In particular, the Knights Hospitaller of St. John occupied Cyprus, the Dodecanese and the facing Turkish coasts for more than two centuries (1306–1522) after they withdrew from Jerusalem in 1187 and from the Levant in 1291. Snails could have been introduced as an item of food or transported with other material including limestone used for building.

Larval stages of trematodes obtained from the freshwater snail Melanoides tuberculata (Cerithioidea, Thiaridae) as intermediate host were studied by using cercarial emergence and crushing snails. Between December 2004 and September 2009 snails from one hundred twenty locations in Thailand were collected every two months for one year at each sampling site. Counts per unit of time method was used in this study, and the samples of snails were collected every 10 minutes per sampling by five collectors. The cercarial stages were examined using shedding and crushing methods. The infection rate was found to be 18.79%, i.e. 6,019 animals infected in a total of 32,026. Nine different types in eighteen species of cercariae were categorized, viz. are (1) Parapleurophocercous cercariae: Haplorchis pumilio, Haplorchis taichui, and Stictodora tridactyla; (2) Pleurophocercous cercariae: Centrocestus formosanus; (3) Xiphidiocercariae: Acanthatrium hitaense, Loxogenoides bicolor, and Haematoloechus similis; (4) Megalurous cercariae: Cloacitrema philippinum and Philophthalmus sp.; (5) Furcocercous cercariae: Cardicola alseae, Alaria mustelae, Transversotrema laruei, Apatemon gracilis, and Mesostephanus appendiculatus; (6) Echinostome cercariae: Echinochasmus pelecani; (7) Amphistome cercariae: Gastrothylax crumenifer; (8) Renicolid cercariae: Cercaria caribbea LXVIII; and, (9) Cotylomicrocercous cercariae: Podocotyle (Podocotyle) lepomis.