Species diversity and DNA barcode library of freshwater Molluscs of South Caucasus

This study provides the first attempt to investigate the molecular diversity of South Caucasian freshwater molluscs (Mollusca, Gastropoda) and lay down the first bricks to build up a DNA-barcode library. In total, 289 COI barcode sequences were obtained from 33 morpho-species belonging to 24 molluscan genera and 10 families that represent nearly 30% of known freshwater molluscan diversity of the South Caucasus region. DNA barcodes were analysed by means of the Barcode Index Number (BIN) and the other tools available in BOLD Systems. Results showed that the knowledge of freshwater molluscs diversity in the South Caucasus is far from comprehensive. For the studied 33 morpho-species, 289 barcodes were clustered into 40 BINs, from which unique BINs were defined for 12 species and five species were characterised with more than a single BIN. From the studied taxa, 60% were characterised larger than 2.2% sequence divergence indicating high genetic variation or cryptic diversity. Within our limited taxonomic coverage, we found one new species for the Republic of Georgia (Galbaschirazensis) and at least three undescribed species belonging to the genera Stagnicola, Segmentina and Anisus. Uniqueness and high molecular diversity of the studied species emphasise the need for further intensive morphological and molecular investigations of the South Caucasian freshwater molluscan fauna.

New data on the valvatiform-shelled Hydrobiidae (Caenogastropoda, Truncatelloidea) from southern Greece

The minute valvatiform-shelled Hydrobiidae are less studied than other hydrobiid gastropods. In this paper, new data on these snails are presented, which have been collected at twelve springs in southern Greece: one in Boeotia, one on Evvoia Island, and ten on the Peloponnese Peninsula. Mitochondrial cytochrome oxidase subunit I (COI) and nuclear histone (H3) have been used to confirm the determinations and infer the relationships of the studied gastropods. They represent the genera Daphniola, Graecoarganiella and Isimerope. New localities, expanding the known geographic ranges, have been presented for Daphniolahadei and Daphniolalouisi. A species of Daphniola found at two localities has been identified as a species new to science, and its description, including the shell, penis, and female reproductive organs is given. Possible relationships between Graecoarganiella and Isimerope are discussed; their representatives are possibly new species. At one locality a single specimen likely represents a new genus: it was found to be most closely related with Islamia, but genetically (p-distance) too distant to be congeneric with Islamia.

Crenobiont, stygophile and stygobiont molluscs in the hydrographic area of the Trebišnjica River Basin

In the paper the crenobiont, stygophile and stygobiont malacofauna of the karst area of Popovo Polje around Trebinje (Eastern Herzegovina, BiH) is presented. The materials were collected from springs, caves and interstitial habitats (with a Bou-Rouch pump) at 23 localities. The following species were found: Pisidium cf. personatum A.W. Malm, 1855, Theodoxus callosus (Deshayes, 1833), Sadleriana fluminensis (Küster, 1852), Radomaniola curta (Küster, 1852), Radomaniola cf. bosniaca (Radoman, 1973), Kerkia briani Rysiewska & Osikowski, 2020, Montenegrospeum bogici (Pešić & Glöer, 2012), Litthabitella chilodia (Westerlund, 1886), Travunijana vruljakensis Grego & Glöer, 2019, a new genus and species of the Sadlerianinae, Emmericia ventricosa Brusina, 1870, Iglica cf. absoloni (A.J. Wagner, 1914), Plagigeyeria tribunicae Schütt, 1963, Paladilhiopsis arion Rysiewska & Osikowski, 2021, Valvata montenegrina Glöer & Pešić, 2008, Radix labiata (Rossmässler, 1835), Galba truncatula (O. F. Müller, 1774), Ancylus recurvus Martens, 1783, Ancylus sp. and the amphibiotic Succinea cf. putris (Linnaeus, 1758). The redescription of the genus Travunijana Grego & Glöer, 2019, applying the characteristics of shell, female reproductive organs and penis, is also presented. The new genus and species are described, based on the shell, penis, radula and fragmentary data on the female reproductive organs. For all species, the mitochondrial cytochrome oxidase subunit I (COI) is applied to confirm the determination; in the case of Travunijana and the new genus, the nuclear histone H3 locus is also used, in order to infer both their distinctiveness and phylogenetic relationships.

Two new species of the Balkan genus Paladilhiopsis Pavlović, 1913 (Caenogastropoda, Moitessieriidae)

The Balkan Peninsula is inhabited by the worldwide most diverse subterranean gastropod fauna. This fauna is still poorly studied, since its habitats are not easily accessible, and its sampled populations are mostly not rich in specimens' numbers. Often only empty shells are known, but the shell is hardly useful, not only in phylogeny reconstruction, but even in species determination. The exclusively obligatory subterranean family Moitessieriidae is especially poorly studied. Representatives of the genus Paladilhiopsis Pavlović, 1913 (Moitessieriidae) collected at three localities, distributed in Croatia and Bosnia & Herzegovina, were studied. The pigmentation of their shells and soft parts, as well as the female and male reproductive organs in one taxon, are presented. The partial sequences of the molecular markers mitochondrial cytochrome oxidase subunit I (COI) and nuclear histone 3 (H3) were used to infer their systematic status and phylogenetic relationships. Two species new to science are described. For one of them, also studied anatomically, 15 specimens were sequenced for COI, and all show the same haplotype.

A new genus and species of Hydrobiidae Stimpson, 1865 (Caenogastropoda, Truncatelloidea) from Peloponnese, Greece

Minute caenogastropod brackish-water gastropods, formerly classified as Hydrobia, are important elements of the brackish-water fauna and were objects of intensive study for many years. Until now, five genera have been distinguished, most of them represented by a number of species, but rather indistinguishable without molecular data (cytochrome oxidase subunit I - COI). In the eastern Mediterranean region, they are still poorly studied. In this paper, we present a new species of "Hydrobia" from the brackish Moustos spring, Arkadia, eastern Peloponnese, Greece. The shell, protoconch, radula, female reproductive organs, and penis are described and illustrated, together with the molecular (COI) relationships with other hydrobiids. All data confirm that these snails represent a distinct taxon, which must be classified as a new species belonging to a new genus. The formal descriptions are given. The closest, sister taxon is Salenthydrobia Wilke, 2003. The molecularly estimated time of divergence, 5.75 ± 0.49 Mya, coincides with 5.33 Mya, which is the time of the Oligocene flooding that terminated the Messinian salinity crisis. During the latter period, brackish "Lago-Mare" habitats were most probably suitable for the last common ancestor of Salenthydrobia and the newly described genus. Later, the Pliocene flooding isolated the Apennine and Peloponnese populations, promoting speciation.

A new hydrobiid species (Caenogastropoda, Truncatelloidea) from insular Greece

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.

A new species of Kerkia Radoman, 1978 (Caenogastropoda, Hydrobiidae) from Bosnia and Herzegovina

A new species of Kerkia, K.briani Rysiewska & Osikowski, sp. nov. is described from the spring Polički Studenac Vrelo (Crkvina), adjacent to the Trebišnjica River (Bosnia and Herzegovina) collected with Bou-Rouch technique, pumped from an interstitial habitat 50 cm below the bottom of the spring. The shell, female reproductive organs, and the penis are described and illustrated. Mitochondrial cytochrome oxidase subunit I (COI) and nuclear histone H3 partial sequences confirm the distinctness of the new species, and molecularly based phylogenetic relationships of Kerkia are briefly presented.

Revealing the stygobiotic and crenobiotic molluscan biodiversity hotspot in Caucasus: Part I. The phylogeny of stygobiotic Sadlerianinae Szarowska, 2006 (Mollusca, Gastropoda, Hydrobiidae) from Georgia with descriptions of five new genera and twenty-one new species

The position of the southwestern Caucasus as a stygobiotic Mollusca hotspot is confirmed. Molecular data of stygobiotic gastropods revealed the diversity of subfamily Sadlerianinae Szarowska, 2006, inhabiting the subterranean environment of Georgia. In addition to the well-known endemic genera Pontohoratia Vinarski, Palatov & Glöer, 2014 and Motsametia Vinarski, Palatov & Glöer, 2014, five more genera were identified in northwestern Georgia as new to the science: Kartvelobia gen. nov., Imeretiopsis gen. nov., Caucasopsis gen. nov., Caucasogeyeria gen. nov., and Hausdorfenia gen. nov. Additionally, 21 new species were found to inhabit the studied area (Samegrelo, Imereti, Racha regions in Georgia).