Materials on the fauna of freshwater pulmonate mollusks of the Zapovednik (Nature Reserve) "Yuganskiy" and adjacent territories

The malacofauna of waterbodies of the State Nature Zapovednik (Nature Reserve)“Yuganskiy” is still underexplored, and the full species list of mollusks is absent in the literature. The inventory of the Zapovednik aquatic malacofauna is needed since freshwater mollusks (snails and bivalves) represent an important component of aquatic coenoses and have high value for fisheries and epidemiological studies. Here, the materials on the fauna of aquatic pulmonate snails (Mollusca: Gastropoda: Pulmonata) of the Zapovednik and some adjacent areas collected during the field season of 2012 are presented. This species list is by no means complete and may serve as the starting point for the full inventory of the Zapovednik malacofauna in the future. We followed the standard techniques of mollusk sampling, fixation and laboratory treatment. Nearly 1200 individuals of pulmonate snails were collected by the authors from 33 waterbodies of different type representing the full spectrum of habitats know for the area studied. As a result, we report the presence of 17 species of pulmonate mollusks belonging to three families (Acroloxidae, Lymnaeidae, Planorbidae). Which species mentioned in the article is accompanied by a short comment on its distribution, bionomics and, if needed, taxonomic position. A brief zoogeographical analysis of the fauna is also provided. Most species of mollusks registered by us belong to the group of widely distributed in Northern Palearctic species. Their ranges are usually characterized as Transpalearctic or Euro-Siberian. Only five species of pulmonates (Anisus borealis, A. stroemi, Lymnaea dolgini, L. saridalensis and L. terebra) may be considered as endemics of subendemics of Siberia. The taxonomic content of the fauna is rather poor. We could not find any representatives of the pulmonate family Planorbidae as well as species of such widespread in Western Siberia pulmonate genera as Armiger, Planorbis, Segmentina. The striking fact is the complete absence of snails of the family Bithyniidae in the area under investigation. Two possible causes of this taxonomic poverty are discussed. First, the sampling effort made in the area is too low to detect all the species of Pulmonata living here. Second, the area studied is located in the upper part of the Bolshoy Yugan River basin that impedes molluscan migration (most aquatic snails use passive mode of dispersal in downstream direction).

Gastropoda, Pulmonata, Freshwater mollusks, Gastropoda, Pulmonate snails, inventory of fauna, Zoogeography, Zapovednik (Nature Reserve) “Yuganskiy”, Western Siberia