Range-constrained co-occurrence simulation reveals little niche partitioning among rock-dwelling Montenegrina land snails (Gastropoda: Clausiliidae)

Geographical and environmental patterns of Carpathian land snail faunas in a region of high endemicity

The land snail faunas of limestone gorges of Romanian Carpathians were sampled to test the effect of geographic and environmental factors on the malacofauna richness and composition. A total of 134 sites within 28 limestone gorges were surveyed during 2011-2019 using a combined strategy of visual search and litter/topsoil analysis. Environmental variables such as geographic location, altitude, climate, microhabitat type, dominant vegetation, tree cover and width of the gorge were recorded to detect the relationship with species richness and composition. While the numbers of species, their identities and their abundance varied greatly among samples, both presence and absence data and quantitative multivariate analyses showed that region and climate or altitude (both strongly associated with region) accounted for far more variation than differences in tree cover and dominant microhabitat. Nevertheless, the effects of different habitat preferences were evident. The mixture of species with very restricted ranges within this Pleistocene refugium and those that have spread widely during the Holocene raise questions about the meaning of region when related to local richness and composition.

Speciation of rock-dwelling snail species: disjunct ranges and mosaic patterns reveal the importance of long-distance dispersal in Chilostoma (Cingulifera) in the European Southern Alps

To better understand the origin of the high diversity and endemism in the Southern Alps of Europe, we investigated the phylogeny and population structure of the rock-dwelling snail group Chilostoma (Cingulifera) in the Southern Alps. We generated genomic ddRAD data and mitochondrial sequences of 104 Cingulifera specimens from 28 populations and 14 other Ariantinae. Until recently, about 30 Cingulifera taxa were classified as subspecies of a single polytypic species. The phylogenetic and population genetic analyses of the ddRAD data and mitochondrial sequences revealed that Cingulifera in the Southern Alps is differentiated into three species. Each of the three Chilostoma (Cingulifera) species occupies disjunct sub-areas, which are separated by areas occupied by other Chilostoma taxa. Neighbouring populations of different species show little or no admixture. Tests indicating that the genetic differentiation of the three Cingulifera taxa cannot be explained by isolation by distance confirmed their species status. The disjunct range patterns demonstrate the importance of stochastic events such as passive long-distance dispersal for the evolution of population structure and speciation in these snails, and of priority effects and ecological competition as important factors influencing species distributions.

Further notes on the taxonomy of the land snail family Clausiliidae Gray, 1855 (Stylommatophora, Helicina) from Myanmar with description of two new species

This study presents a complete species list of the door snails inhabiting Myanmar, updated to now include 33 taxa, and provides taxonomic notes together with a re-description of the shell, radula, and genitalia for 13 species and subspecies, including Oospiraphilippiana, the type species of the genus Oospira. The snails previously treated as subspecies or synonyms of Oospiragracilior and Oospiramagna are reclassified and recognized as distinct species. The lectotype of Oospirainsignis has been clarified and an illustration of the original type specimen provided. A long-overlooked species, Oospiraandersoniana, has been collected and redescribed herein. Two new species from the limestone karsts in the Salween River Basin are introduced: Oospiraluneainopsis Man & Panha, sp. nov. and Oospirazediopsis Man & Panha, sp. nov. A synoptic view of all clausiliid taxa known from Myanmar is presented along with taxonomic information and distributional records. Photographs of the type materials for all taxa are provided for further comparison or, if unavailable, photographs of the examined specimens or the original figure from the literature.

Contribution to the taxonomy and distribution of Aciculidae (Mollusca: Gastropoda: Caenogastropoda) in Albania and the surroundings

Reviewing historical and recently collected material of family Aciculidae from Albania and the neighbouring region, we synonymized two species and one subspecies, namely Platyla corpulenta Subai, 2009 under Platyla procax Boeters, E. Gittenberger Subai, 1989; Platyla ceraunorum A. Reischtz, N. Steiner-Reischtz P. L. Reischtz, 2016 under Platyla similis (Reinhardt, 1880) and Renea kobelti albanica Boeters, E. Gittenberger Subai, 1989 under Renea kobelti (A. J. Wagner,1910). Four aciculid species are first mentioned for Albania: Platyla similis and Platyla procax that replace their junior synonyms; and Platyla feheri Subai, 2009 and Platyla gracilis (Clessin, 1877) that are new to the country. Furthermore, new distribution data are provided for Platyla albanica Subai, 2012, Platyla banatica (Rossmssler, 1842), Platyla wilhelmi (A. J. Wagner, 1910) and Renea kobelti (A. J. Wagner, 1910). In the light of new distribution data, their conservation statuses according to IUCN criteria are assessed at the national level and, when necessary, are re-assessed at global level.

A molecular phylogeny of Geotrochus and Trochomorpha species (Gastropoda: Trochomorphidae) in Sabah, Malaysia reveals convergent evolution of shell morphology driven by environmental influences

There are currently eleven Geotrochus and four Trochomorpha species in Sabah. The primary diagnostic character that separates the two genera is the intensity of sculpture on the shell upper surface. All Trochomorpha species have a coarse nodular sculpture while Geotrochus species has a non-nodular sculpture or smooth shell. However, it is known that shell characters are often evolutionary labile with high plasticity in response to environmental factors. Hence, identifying the phylogenetic and ecological determinants for the shell characters will shed light on the shell-based taxonomy. This study aims to estimate the phylogenetic relationship between Geotrochus and Trochomorpha species in Sabah based in two mitochondrial genes (COI, 16S) and one nuclear gene (ITS) and also to examine the influence of temperature, elevation and annual precipitation on the coarseness of shell upper surface sculpture and shell sizes of the species of both genera. Additionally, we also investigated the phylogenetic signal of the shell characters. The phylogenetic analysis showed that Geotrochus and Trochomorpha species are not reciprocally monophyletic. The phylogenetic signal test suggested that shell size and upper surface sculpture are homoplastic, and these shell traits are strongly influenced by elevation and annual precipitation, particularly at the cloud zone of Mount Kinabalu. The highland species of both genera have a coarser shell surface than lowland species. The shell and aperture width decrease with increasing elevation and annual precipitation. In the view of finding above, the current taxonomy of Geotrochus and Trochmorpha in this region and elsewhere that based on shell characters need to be revised with sufficient specimens throughout the distribution range of the two genera.

Ecological specialization resulting in restricted gene flow promotes differentiation in door snails

We tested the hypothesis that ecological specialization that affects dispersal promotes diversification by a comparison of the genetic structure of two sister species of door snails across their broadly overlapping ranges in the Crimean Mountains. The hypothesized effect of ecological specialization on diversification is supported by STRUCTURE analyses that showed that Mentissa gracilicosta that is restricted to limestone rocks, is subdivided into several distinct clusters, whereas all populations of the species adapted to more continuous habitat, the forests-dwelling Mentissa canalifera, were assigned to a single cluster. Furthermore, it is supported by AMOVAs that showed that a larger part of the genetic variation of M. gracilicosta is apportioned among populations than in M. canalifera. The stronger genetic differentiation of the M. gracilicosta populations corresponds to their more distinct morphological differentiation that resulted in the classification of M. gracilicosta into several geographical subspecies, whereas the more continuously distributed M. canalifera was not subdivided into subspecies. The stronger differentiation of populations of M. gracilicosta compared to M. canalifera can be ascribed to reduced gene flow between the isolated populations of M. gracilicosta and to founder events associated with the long distance dispersal events that are necessary for the colonization of isolated rocks by M. gracilicosta. In Central Europe, the Pleistocene climatic oscillations selected for species with high dispersal abilities, whereas the more stable climate in southern Europe facilitated the non-adaptive radiation of rock-dwelling door snails. Thus, the intrinsic ecological properties of these species groups contributed to the latitudinal diversity gradient.