A detailed study of morphology of the rare phytophilous cladoceran Camptocercus lilljeborgi Schoedler, 1862 revealed that populations from Eastern Siberia and Far East of Russia belong to a new species. C. smirnovi sp. nov. differs from C. lilljeborgi in body shape, morphology of ventral margin of valves, morphology of postabdomen, and length of IDL seta 1 of the thoracic limb I. C. lilljeborgi s. str. is distributed in Europe and Western Siberia, therefore, the lilljeborgi-group provides an example of the western-eastern differentiation in Northern Eurasia. Some characters of taxa from the lilljeborgi-group are convergently similar to the characters of the species of genus Graptoleberis Sars, 1862; both groups are adapted to a snail-like crawling on the surface of water macrophytes.

The mouth areas of large rivers can serve as a good model of heterogeneity sites with a pronounced trophic gradient to assess the impact of the degree of eutrophication on different plankton communities. The aim of this research was to identify the possible response of the diversity indicators of phyto- and zooplankton communities to trophic gradients in the mouth area of two large tributaries of the reservoir, formed in the Middle Volga River (Russia). Both linear regression models and canonical correlation analysis (CCA) were used to assess the role of abiotic and biotic predictors in the structural organization of plankton communities and to assess the changes in the parameters of the species plankton community structure in the trophic gradient. It was found that the species diversity (Adjusted R² = 0.116) and evenness (Adjusted R² = 0.114) of phytoplankton significantly decreased with an increase in the degree of eutrophication, while the species diversity (Adjusted R² = 0.059) and evenness (Adjusted R² = 0.073) of zooplankton increased. According to the CCA models, electrical conductivity (EC) explained the largest proportion of the observed dispersion. The Trophic State Index (TSI) explained 3.0% of the total variance in the phytoplankton community species structure and 7.8% in the zooplankton one. The variation in phyto- and zooplankton dominant complexes generally corresponded to the well-known patterns of plankton species succession in the gradient of trophic conditions and can be considered as a classic manifestation of the cascade effect in the food chains of freshwater plankton communities. Our results highlight the necessity of studying the mouth river areas, as well as applying an integrated approach to investigating the response of plankton communities to eutrophication processes of continental water bodies.

In view of frequent findings of the alien North American rotifer Kellicottia bostoniensis (Rousselet, 1908) in water bodies and watercourses of Russia, the generalization of information about its loca

Находка тропического вида Thermocyclops taihokuensis Harada, 1931 (Copepoda: Cyclopoida) в европейской части России

—Information on the functional traits of the most widespread species of freshwater zooplankton (Rotifera, Cladocera, and Copepoda) in European Russia was collected and analyzed. Our database includes 355 species described by four traits, namely, the maximum body length, trophic group, feeding type, and movement type. Cluster analysis based on Gower’s functional distances shows that freshwater zooplankton can be classified into 19 groups with different ecological roles. The characteristics of each functional group identified are presented. We believe it to be fundamentally important to build a unified classification using all available data and traits applicable to all three main taxonomic groups of zooplankton. Comparison with the existing ecological zooplankton classification proposed by Yu.S. Chuikov has demonstrated a number of advantages of our approach. Several ecological groups in Chuikov’s classification are represented by more fractional categories in our classification. Our system of functional groups can be used in studies of the structure of zooplankton communities based on direct cluster analysis and ordination or based on functional distances between samples. To calculate the functional similarity between species, one can use our database of traits, which is contained in the Appendix. Analysis based on functional groups gives a better understanding of the community structure than conventional ordination, which takes into account only the taxonomic affiliation of species. The approach used for functional group identification can be useful in assessing the functional diversity and identifying patterns in the dynamics of freshwater zooplankton communities. The database of functional traits of zooplankton can be used to check the relationship of functional traits with environmental variables.