Molluscan Fauna Research Articles

Update of the non-marine (terrestrial & freshwater) molluscs systematic inventory occurring in Santa Catarina State/ SC, Central Southern Brazil region

Introduction: The survey of the mollusc fauna (malacofauna) of a geopolitical region (State) is important from several aspects, reaching several important sectors of knowledge. So if all regions could do the same we would have within, a few years, expanded and completed the catalog of molluscs in Brazil, with much still to be added with regard to terrestrial and freshwater fauna. Objective: Updated general rеᴠiеw of the inventory of non-marine molluscs occurring in the Santa Catarina State/ SC, subtropical Central Southern portion of the Brazilian territory. Methodology: Organization of a occurring State species taxonomic checklist and their corresponding reference database, comprising the regional knowledge formally produced around the theme at least since the year 2003. Results and Conclusions: Confirmed and recorded regional total of 241 species (202 Gastropoda & 39 Bivalvia), among which at least 86 (79 Gastropoda & 7 Bivalvia) exhibit radicals synonymical (among others) changes recently reported through the global platform "MolluscaBase" and available literature of recent production, taxonomically included all in 95 genera (83 Gastropoda & 12 Bivalvia) and 40 families (35 Gastropoda & 5 Bivalvia), with aggregated additional information about their known biogeographical distribution in the territorial space of the State.

Analysis of fauna of mollusks, pollen assemblages and sedimentary environments in the Taganrog Bay of the Sea of Azov

The paper presents the results of a comprehensive study of well sections drilled on the coastal spits of the Taganrog Gulf of the Sea of Azov and bottom sediment columns selected in the water area. A detailed analysis of the early malacological communities, an important participant in the sedimentary process, made it possible to trace changes in their living conditions in the Holocene. Based on determining the absolute age (14C) from the valves of mollusk shells buried in situ, it is shown that at the beginning of the Phanagorian regression, in the area of the distal part of the Dolgaya Spit, there was a sea reservoir with an Azov-Black Sea complex of reference species. Based on the results of palynological analysis, changes in the natural conditions of the Azov region over the past few thousand years have been reconstructed and arid and humid climatic phases have been identified.

Impact of river discharge and suspended sediments on the nearshore benthic environment along the Indian southwest coast

River discharge into the sea and its implications on the environmental setting and fauna in the nearshore represent the intricate interactions among the atmosphere, hydrosphere, lithosphere, and biosphere. This study, based on in-situ and satellite data, presents how spatially varying river discharge laden with suspended sediments structure the hydrography and the nearshore benthic environment over a 590 km southwest (Kerala) coast of India. The 41 rivers that discharge along the Kerala coast are monsoon-driven; they are small but swift and cumulatively supply huge amounts of freshwater and suspended sediments into the Southeastern Arabian Sea (SEAS) during the Southwest Monsoon (SWM) when around 70 % (1925 mm) of the yearly rainfall occurs. These rivers are distributed unevenly along the coastline, with twenty-four of them discharging in the northern region (10.9–12.5°N), nine in the central (9.2–10.9°N), and eight in the south (8–9.2°N). During the SWM, plumes of low salinity (<32) with high clay content were widespread in the northern and central regions of the study area due to heavy river discharge and the presence of crystalline rocks and laterite deposits. In contrast, the low salinity plumes and suspended sediments were markedly low in the southern region due to limited river discharge and a predominance of sedimentary rocks and coastal alluvium that supported sandy sediments. This resulted in a spatial change in benthic sediment texture as well, with the central and northern regions more silty or clayey, while the south was sandy. Interestingly, the sandy south section had a noticeably higher faunal abundance than the rest of the region with an increased abundance of sensitive fauna of molluscs and echinoderms. This is a clear case of how spatially varying river discharge and sediment flux impact the nearshore environment and fauna.

Species diversity of Molluscan fauna of Madhav National Park, Madhya Pradesh, India

The present study is based on the Molluscs samples present in National Zoological collection of Central Zone Regional centre, Zoological Survey of India, Jabalpur and the available Literatures. The Samples were collected back in the year from 1970 to 2017 by different tour parties surveying Madhav National Park and its vicinity over the years. The current study reveals the occurrence of 21 species of freshwater and Land mollusks belonging to 18 genera, 10 families, 7 orders of 2 classes of Phylum Mollusca. This is the first report of the mollusks species from this area which will help in evaluate the mollusks diversity of Madhav NP, Shivpuri.

The Biparjoy Cyclone Impact on Molluscan Fauna Inhabiting Clifton Beach, Karachi

The Biparjoy Cyclone Impact on Molluscan Fauna Inhabiting Clifton Beach, Karachi

The use of the malacofaunistic method for reconstructing the palaeoecological conditions of the late late pleistocene to holocene based on material from the Tetyukhinskaya Cave Site, Southern Far East, Russia

Results of the study of terrestrial mollusc shells from the unconsolidated deposits of the Tetyukhinskaya Cave, Dalnegorsk, Primorsky Krai, Russia are presented. Brief species descriptions of the molluscs and their images complete the scarce information on the fossil Quaternary mollusc fauna of the region. With the help of malacological analysis, characteristic zones and malacological complexes were identified, which were used as indicators of the habitats near the cave entrance and in the adjacent territory. The data concerning the palaeoecological conditions of individual mollusc species confirm the development of broad-leaved and mixed forests, alongside open meadows with herbage vegetation in the region near the cave, towards the end of the Late Pleistocene and in the Holocene.

Nematodes of concern to public and animal health associated with the invasive snail Achatina fulica, in Sergipe, Northeastern Brazil

The giant African land snail Achatina fulica is known to be the intermediate host of a number of nematode species that are prejudicial to human and veterinary health, being also an agricultural and urban pest. The present study investigated the presence of nematodes in A. fulica and other terrestrial mollusks in 24 municipalities of Sergipe State, northeastern of Brazil, in the dry and rainy seasons. In 2019 and 2020, the specimens were collected in standard 20 m × 10 m plots (10 min/01 collector), while in 2021, they were collected by convenience sampling. The nematode species were identified based on sequencing of the mitochondrial Cytochrome C Oxidase Subunit I (COI) gene and the ribosomal nuclear Internal Transcribed Spacer (ITS 2). Specimens of A. fulica infected with Angiostrongylus cantonensis, a nematode that causes eosinophilic meningitis (EM) in humans and animals, were collected in four municipalities. Two nematodes of veterinary importance were also identified, Aelurostrongylus abstrusus and Cruzia tentaculata in seven municipalities. This is the first record of Cruzia tentaculata in Sergipe. Free-living nematodes were also found in 18 municipalities. One of these species – Caenorhabditis briggsae – was identified in the municipality of Itabaiana. Specimens of other mollusks species were also collected. Only one of these mollusks, C. fasciata from Japaratuba, was found infected with free-living nematodes. A. fulica showed greater positivity for nematodes in the dry season, especially in the regions of Lower São Francisco River, Greater Aracaju and South Central Sergipe. The probability of infection increased when mollusks were larger and more recurrent in plots. Given that A. cantonensis is the etiological agent of EM and was found associated to A. fulica in four municipalities, it will be important to implement programs of continuous monitoring of the mollusk's fauna, combined with educational programs that provide information necessary to control A. fulica.

Snails of ‘sky islands’ above an equatorial desert: Terrestrial molluscs on four isolated mountain ranges in northern Kenya

AbstractThe mountains of northern Kenya (Ndoto, Nyiro, Kulal and Marsabit) are separated by semi‐arid plains uninhabitable for most terrestrial molluscs (snails and slugs). Nevertheless, each “sky island” supports a little‐known forest mollusc fauna. The diversity and endemism of these faunas are addressed here based on surveys and the limited records available in the literature. In total 75 forest mollusc species and subspecies were found, including six previously undescribed Streptaxidae and many first records. Most previously recorded taxa were refound. The richness of faunas is broadly comparable to that of other Kenyan forests surveyed using similar methods (Ndoto 41 taxa, Nyiro 40, Kulal 33, Marsabit 34). A large proportion of the forest taxa (24 taxa, 29%) are endemic to Kenya north of the Mathews Range. More than half of these (14 taxa, 17% of the total) are known only from a single mountain range. At Nyiro, where different forest types were compared, fewer endemic species were found in Juniper forest than in other forest types. Moving northwards along the Ndoto‐Nyiro‐Kulal chain, diversity declines while endemism increases, perhaps reflecting increasing isolation from the southern forests, but the trends are not significant when Marsabit is included. Across the four ranges, neither diversity nor endemism is clearly linked to the isolation, maximum elevation, forest cover or geological origin of each range (Kulal and Marsabit are volcanoes, while Nyiro and Ndoto are uplifted basement rock). Instead, the unique circumstances of each range create a distinctive set of isolated faunas.

The terrestrial gastropods (Mollusca: Gastropoda) of the Mavrovo National Park, North Macedonia

Sixty-one species taxa of land gastropods are known for Mavrovo National Park, and 34% of them are species taxa of high conservation value. Considering the unsystematic surveys in the area, it can be assumed that in the future the number of species taxa will significantly increase. The status of Mavrovo as a national park under high protection, and there are no immediate threats to the malacofauna. Potential problems for invertebrate communities, including snails, would be big destructive changes in their habitats and especially the presence of hydropower projects and stone quarries. The protection of the species habitats from human activity and different types of modification is the best protection measures for the mollusk fauna in Mavrovo National Park.

THE SIGNIFICANCE OF THE PLEISTOCENE AQUATIC FAUNA OF MOLLUSKS FOR THE REPRODUCTION OF SEDIMENTATION CONDITIONS IN WESTERN UKRAINE

The territory of Western Ukraine is characterized by the development of a wide range of genetic types of continental formations. The Carpathian Mountain Country (properly the Carpathians, East Carpathian Foreland, and Transcarpathia) and the highly fragmented parts of the Volhynia and Podolia Uplands are characterized by a special diversity. The time range of their formation is vast – from the Early Pleistocene to the present. The complexity of the structure of the Quaternary sequence gives rise to discussions about the origin of some components of anthropogenic accumulations. Despite the fact that most of the challenging issues have already been resolved, we find debatable information in the works of some researchers of the 20th and even the 21st centuries about the aqueous origin of the thick sequences of anthropogenic sediments covering the terraces of the Dniester and Dnieper basins. The researchers use many methods to solve the issue of the deposit genesis. Some of them are based on the study of paleontological (including paleomalacological) remains, which are often found in both aqueous (alluvial, lake, swamp) and aerial (primarily loess) formations. Malacofauna has been used since the second half of the 19th century to determine the age, conditions of formation, and origin of the deposits. To establish the origin of sediments we have used the mollusk fauna in this work, which can be often found in the formations of the studied territory. The interpretation of the fauna is debatable in the sections where several genetic types of formations are exposed, primarily alluvial and eolian–deluvial loess. This type of combination of deposits is found in outcrops on the numerous terraces of the Dniester and the terraces of its East Carpathian Foreland’s and Podolia tributaries. The results of the research obtained by us using paleomalacological studies correlate well with data obtained using other methods. Such methods include actual field observations, as well as lithological, palaeopedological, paleontological (study of fossil mammals, fish, spores, and pollen), archaeological, and other methods. The results presented in this work made it possible to establish the genesis of some components of polygenetic complex strata, as well as testify to the effectiveness of the applied research method. Keywords: anthropogen; malacofauna; alluvium; loess; paleogeography; Podolia; East Carpathian Foreland.

Malacofauna of Crimea as a possible source of introductions to other regions of Ukraine: land snails of non-Crimean origin

Background. Due to global climate changes, a number of land mollusc species, previously known only from southern Ukraine or only from Crimea, are increasingly being recorded in different parts of the country. Apparently, not only species of the Crimean origin but also some other molluscs, native or alien to the Crimean Peninsula, could have been introduced from Crimea in different time periods. Therefore, the main purpose of this study was to generalise and give a critical analysis of data on the present distribution in Ukraine outside Crimea for 8 such species, whose primary source of dispersal could be, at least partially, the Crimean Peninsula. Materials and Methods. We used the results of our own long-term (from 1994 to 2023) research of the land mollusc fauna in different parts of Ukraine, examined collections of other researchers and amateurs, numerous stock materials of the State Museum of Natural History in Lviv, analysed a number of literature sources from the beginning of the 20th century to the present day, as well as reports from two citizen science databases (iNaturalist and UkrBIN). Results and Discussion. We have sequentially analysed the available data about the present distribution and chronology of discovery in different administrative regions of Ukraine outside Crimea for Cecilioides raddei, Phenacolimax annularis, Oxychilus deilus, Xeropicta derbentina, X. krynickii, Monacha cartusiana, Eobania vermiculata, as well as Helix lucorum with the shell colouration characteristic of the mountainous Crimea. It has been established that one or more species have now been reliably recorded in all parts and almost all administrative regions of Ukraine, with the exception of Sumy and Kirovohrad ones. Conclusion. The conducted analysis confirms the potential influence of Crimea on the formation of the present species composition of alien land molluscs not only in the south, but also in other parts of Ukraine. Most of the analyzed species are so far known only from those administrative regions that border the Black and Azov Seas. Two species, X. derbentina and M. cartusiana, are now rather widespread in Ukraine, but most of their known records were made no earlier than 1990s. The data systematized in this study can become the basis for monitoring the further spread of the species under study into different parts of Ukraine, which may become especially relevant in the post-war period.

Mid-Holocene marine faunas from the Bangkok Clay deposits in Nakhon Nayok, the Central Plain of Thailand.

Based on several field investigations, many molluscan shells and chondrichthyan teeth, together with other invertebrate and actinopterygian remains were found from the marine Bangkok Clay deposits in Ongkharak, Nakhon Nayok, at a depth of ~ 5-7 m below the topsoil surface. Animal macrofossils recovered from these Holocene marine deposits were identified and their chronological context was investigated in order to reconstruct the paleoenvironments of the area at that time. The majority of marine fossils recovered from the site consist of molluscs, with a total of 63 species identified. Other invertebrate species include a stony coral, a mud lobster, barnacles, and a sea urchin. The vertebrates are represented by fish remains, including carcharhinid shark teeth from at least nine species, stingray and trichiurid teeth, and one sciaenid otolith. The molluscan fauna indicates that the paleoenvironments of the area corresponded to intertidal to sublittoral zones, where some areas were mangrove forests and intertidal mudflats. The fish fauna is dominated by the river shark Glyphis, indicating freshwater influences and possibly occasional brackish conditions. The carbon-14 analysis of mollusc and charcoal remains shows that deposition of the marine sediment sequence began during the mid-Holocene, spanning approximately from 8,800 to 5,300 cal yr BP. This study provides in-depth insights into the diversity of fishes, marine molluscs, and other invertebrates from the Bangkok Clay deposits, supporting the existence of a marine transgression onto the Lower Central Plain of Thailand during the mid-Holocene.

Late Miocene mollusks from the Dar Pahn Unit, Makran, SE Iran

Diverse, abundant and well-preserved mollusk fauna are here reported for the first time from the eastern coast Makram area, where Upper Miocene (Tortonian) sediments of the Dar Pahn Unit crop out, representing shoreface tidal influenced deposits composed mainly of ligh-gray marls. Multiple articulated bivalves and completely preserved the gastropod and bivalve shells indicate little or no transport at all from the original habitat of the mollusk assemblage. A total of 313 specimens, from which 271 correspond to gastropods, were identified only at generic level, since the purpose of this contribution is to offer an introduction to this exceptionally well-preserved mollusk assemblage. Previous studies of the area include detailed nannoplankton biostratigraphy and the report of a balaenopterid cetacean. Future studies include the detailed identification of the specimens, along with sediment analysis in order to find protoconchs and offer an extended version of this introductory report.

The Hasli Formation of the Irchel Plateau – A key record for older Early Pleistocene interglacial sediments in northern Switzerland

In the Alpine region of Central Europe, terrestrial Early Pleistocene deposits with preserved faunal and botanical remains are rare. The predominantly gravelly Höhere Deckenschotter (HDS) deposits of northern Switzerland and adjoining south-western Germany are considered the oldest Quaternary sediments in the northern Alpine Foreland, linked with the first extensive Quaternary Alpine glaciations.This multidisciplinary study investigates the Hasli Formation (HF), a unique silty unit with well-preserved biological remains within an HDS sequence at the Irchel Plateau north of Zürich, providing new climatic and environmental data for these exceptional deposits, as well as crucial information about their age. Systematic mapping of the HF, in addition to the underlying and covering gravel units, has been coupled with sedimentary logging and biostratigraphic analysis at several sites. The HF is present over an area c.4 by up to 1.4 km, and where studied is 1.6–6.2 m thick. The sediments and biological material are indicative of overbank deposits accumulating within the damp floodplain of a large meandering river.The recovered small mammal remains are from eight arvicolid species or genera, including Mimomys pliocaenicus, M. reidi/tigliensis and Clethrionomys cf. kretzoii, which became extinct c.1.8 Ma, and Pliomys episcopalis/simplicior, which first appeared c.2 Ma ago. The over 75k identified molluscs, include c.72k coming from 89 terrestrial species and over 3k from 28 aquatic taxa. The molluscan faunas from all locations where the HF has been studied share important biostratigraphic marker species, and indicate analogous climatic and environmental conditions. The marker species include several that became extinct during the Early Pleistocene, of which Clausilia stranzendorfensis and Cochlostoma salomoni, present throughout the HF, are the most important as they disappeared c.1.8 Ma. Many marker species have modern or palaeo-distributions that lie far to the west, south and east of the Swiss Plateau, showing that the climate was much warmer than today, typical for the Tiglian warm stage. The alluvial floodplain was covered by rather dense, mature woodland.Amino acid (AA) analysis shows that molluscan remains from the HF are among the oldest of the Quaternary shell material studied from across the Swiss Plateau. Palaeomagnetic data shows a change from reversed to normal polarity within the upper part of the HF. When combined, the small mammal and molluscan remains, palaeomagnetic measurements, AA geochronology and sedimentary data, suggest an age of 2.1–1.8 Ma for the HF. Recently produced cosmogenic dates bracket the age of the HDS gravels beneath the HF to depositional periods between 2.6 and 0.9 Ma, with the youngest ages being in disagreement with our findings. The abundance and diversity of the molluscs from the Irchel Plateau, with several rare extinct species, together with a notable small mammal assemblage, make this a key palaeontological site and an important reference point for European Quaternary biostratigraphy.

First record of Arionvulgaris Moquin-Tandon, 1855 (Arionidae) from Armenia.

Arionvulgaris Moquin-Tandon, 1855 is amongst the fastest-spreading terrestrial slugs Europe-wide. In recent years, it has been recorded in Canada, Mexico and continues to expand eastwards into Eurasia. Renowned for its high invasiveness, combatting its swift spread creates significant challenges in organising effective preventative measures. This study presents the first record of Arionvulgaris from Armenia, which is the second record of this species' invasion of the Caucasus. In 2022, a substantial population of A.vulgaris was observed close to the City of Stepanavan, which is also the first record in Armenia of the family Arionidae. How the species was introduced to Armenia remains unknown. Identification of Arionvulgaris was conducted, based on external and genital morphology and mitochondrial CO1 (cytochrome c oxidase subunit 1) gene sequencing, revealing notable similarities with Central European clades. Our results confirm the introduction and distribution of A.vulgaris to Armenia. Invasion of such species into Armenia will require additional monitoring and would be aided by further research on Armenia's mollusc fauna in the future.

Miocene instead of Jurassic: the importance of sound fieldwork for paleontological data analysis—a reply

In their detailed comments, Das et al. (2023) try to discount our arguments that the strata cropping out at the so-called Jhura pond locality are not Late Jurassic in age but Miocene. We wrote this paper (Fürsich et al., 2023) because of the far-reaching conclusions that have been drawn from the molluscan fauna at that locality, in particular with respect to the evolution of turritellid gastropods and the evolution of drilling predation by naticid gastropods. We still maintain that the beds containing abundant turritellids are not Jurassic but Neogene, most probably Miocene, in age. In no way do we contest the various analyses on the material collected from the outcrop by the authors, but just the erroneous age assignment of the strata. In order to keep this reply short, we support our point by referring to just to two aspects: the position of the outcrop and the composition of the fauna. Rather than refuting each of the other arguments of Das et al. (2023), we think that a joint visit to the locality would be more productive for arriving at a consensus on the origin and age of the fauna of the Jhura pond locality.

Patterns of distribution of mollusc fauna associated with Halopteris scoparia (Linnaeus) Sauvageau: a baseline study in the Azores archipelago helps understanding the impact of climate change/invasive species on biodiversity

Patterns of distribution of mollusc fauna associated with Halopteris scoparia (Linnaeus) Sauvageau: a baseline study in the Azores archipelago helps understanding the impact of climate change/invasive species on biodiversity

PALAEOECOLOGICAL SITUATION IN PRE-DELTA AREA OF THE NORTH CASPIAN SEA DURING THE HOLOCENE

Palaeoecoligical reconstructions of predelta area of the North Caspian Sea were based on the multidisciplinary study of the core from the Rybachya borehole containing the Holocene deposits. Geochemical, grain size, mollusk fauna, diatom and ostracod analyses were performed, and the radiocarbon dating was carried out. The structure of deposits reflects palaeogeographic events of different scales including the inception of a palaeoincision in the Lower Khvalynian deposits, accompanied by erosion of the Upper Khvalynian deposits; its development during the Mangyshlak regression and gradual filling during the multistage Holocene Neocaspian transgression. The Holocene age of the deposits filling the palaeodepression is confirmed by radiocarbon dates - 8070 ± 110 and 7020 ± 140 cal. BP. The paleontological data indicate the interchange of tranquil and dynamic water regimes and the quasicyclical change in the conditions of the water basin, from brackish to freshwater and to marine during the stage of sedimentation, corresponding to the presentday conditions on the North Caspian shelf.

Recent and subfossil malacofauna of Witkowe Rocks in the Jerzmanowice area (Kraków-Częstochowa Upland, Southern Poland)

Malacological analysis was carried out on the deposits filling small karst forms within Witkowe Rocks in the southern part of the Kraków-Częstochowa Upland (Southern Poland). The study included six profiles and was supplemented by observations of the contemporary mollusc fauna inhabiting the area. Four types of subfossil faunal assemblages, characterised by different taxonomic composition and zoogeographic and ecological structures, were identified. The observed diversity of malacofauna indicates that the sediments filling the analysed forms accumulated in different climatic phases of the Holocene. In the oldest deposits, cold-loving taxa no longer found in the Upland were common. These sediments represent the Early Holocene or Late Glacial. The younger generation of fillings included an assemblage with shade-loving taxa with high thermal tolerance representing the Early Holocene. In the most recent fills, assemblages with composition and structure similar to contemporary malacocoenoses are present, varying depending on local environmental factors and corresponding to the period of the last few hundred years. No significant anthropogenic conversion of habitats was identified within Witkowe Rocks, and the observed diversity of malacofauna is due to natural factors operating at a local scale.

Middle Miocene (Late Badenian) microvertebrates from Hidas, SW Hungary

Up to the present, no terrestrial vertebrate fauna has been published from the pre-Pannonian Miocene of SW Hungary. In 2022 a microvertebrate assemblage was unearthed from a lime mud bed of the Middle Miocene Hidas Formation, in an abandoned coal mining field close to Hidas in the Mecsek Mts. The herpetofauna and the rodent material are described here. Fossil findings point to the Late Badenian MN 7+8 Zone, which, together with the earlier results based on the marine mollusc fauna, narrows the age of the unit to ~13.5–13.3 Ma. The amphibians and reptiles are aquatic, semiaquatic or periaquatic forms. Sedimentary features and the accompanying freshwater gastropod fauna are indicative of a shallow pond or a paludal depositional environment. Crocodylian finds reported earlier from the Hidas Formation indicate a subtropical climate, just before the end of the Miocene warm period in Central Europe. Among the rodents, glirids and flying squirrels as well as Democricetodon and Megacricetodon indicate the presence of humid arboreal vegetation around the site. The rodent taxa are well known from the Middle Miocene faunas of northern Hungary, western Romania and from the Upper Freshwater Molasse of southern Germany and Switzerland. The rodent material does not show characteristics of an insular fauna, e.g. gigantism or endemism. Consequently, although the coeval palaeogeography of the region has been described as an archipelago in the Central Paratethys, with the Mecsek Mts. being one of the islands, the area must have had ecological connections towards the northern and eastern parts of the Pannonian Basin, and the marine areas within the archipelago did not form a barrier against the distribution of microvertebrates. The corridor could have been located towards the NE from the Mecsek Mts., across the elevated basement blocks of central Hungary.