Volume 28

This paper summarizes the mechanisms behind the patterning of the intra-population spatial arrangement of the land snail Vallonia pulchella (Müller, 1774) in terms of edaphic and vegetation properties. The molluscs were collected from a regular grid in recultivated soil (the research station of Dnipro State Agrarian and Economic University, Pokrov, Ukraine). As predictors of the snail population abundance, spatial variables were used, as well as edaphic and vegetation indices. It is shown that V. pulchella to prefer microsites characterized by higher soil electrical conductivity, which contain larger aggregate fractions with low mechanical impedance and the low temperature at the depth of 0-10 cm, with a more developed dead plant layer, low-light and low hygromorph and heliomorph index values of the vegetation.

37 species of the land molluscs were identified in the material collected in 2002-2017,  many being earlier unknown from Zaporozhye region. In total 39 species of molluscs can be considered as reliably recorded from this region. The presence of some species is the result of anthropochory. This concerns first of all those land snails which have spread from the Crimea: Brephulopsis bidens, B. cylindrica, Phenacolimax annularis, Oxychilus deilus, Monacha fruticola, Xeropicta derbentina, X. krynickii, Eobania vermiculata, Helix lucorum. One species (Xerolenta obvia) was introduced to Zaporozhye region from the western part of Ukraine. The data obtained made it possible to clarify the current distribution of Helicopsis retowskii and Chondrula tridens martynovi over the territory of Ukraine.

A comparative analysis of the camera eyes of gastropod pulmonate molluscs Cepaea nemoralis and Cepaea hortensis was carried out on the basis of original and published data. It was demonstrated that the eyeballs and their main components in C. nemoralis and C. hortensis have more similarities in morphological and optical properties than in anatomical parameters.

At the end of the XX – beginning of the XXI century 85 species of the land molluscs of 49 genera and 25 families were reliably registered in the steppe zone of Ukraine. The highest species richness was recorded in the northern steppe subzone (79 species). The main centers of the species diversity are the Donetsk Upland (65% of the total number of species) and the western part of the Black Sea Lowland with the southern spurs of the Podolian Upland adjoining it (55%). The modern composition of the land molluscs fauna of the steppe zone is influenced by the proximity of the Caucasus (for the southeast of Ukraine), the Podolian Upland (for the North-Western Black Sea coast) and the Crimea (for the entire investigated territory). Anthropochory plays an important role in the formation of the land molluscs complexes in the steppe zone of Ukraine.

The locations of Boreoelona contortrix in the waterbodies of Western Siberia and Kazakhstan are reported as well as the data on morphology of shells and copulatory apparatuses of the species from different parts of its range. The interpopulation variation is considered. On the basis of anatomical and morphometric study, it has been shown that there are no statistically significant differences between males and females of B. contortrix. Some problems related to taxonomic diagnostics of the Boreoelona snails are discussed.  

Morphological and optical properties of tentacular epidermis and cornea of the eyes of some species of terrestrial gastropod pulmonate molluscs were studied and their evolutionary transformations were estimated. It was demonstrated that all examined properties of tentacular epidermis and cornea of those species are typical for terrestrial pulmonates. In the course of evolution tentacular epidermis of terrestrial pulmonate molluscs was modified to less extent than cornea, and both these structures underwent minor changes in comparison with analogous structures of the eyes of marine prosobranch molluscs.

The new data about seasonal dynamics of species composition, abundance and biomass of molluscs on soft sediments in the corner part of the Sevastopol bay were analyzed. 24 species of molluscs were recorded in 2006-2007. The microdistribution of Mollusca at stations depends on salinity. The trophic structure of molluscs’community was determinated and includes 6 trophic groups.

Only four species of the family Cancellariidae had been reported from the Arctic. However, known distribution of three of them had been limited by the extreme north of the eastern Atlantic so far. The present paper describes findings of Admete contabulata Friele, 1879 from the Barents and the Kara seas and Iphinopsis inflata (Friele, 1879) from the Pacific part of the Arctic Ocean. Lectotype for Admete contabulata is here designated.