Testaceans (Testacea, Protozoa) of taiga soils in Western Siberia (Surgut Polesye)

We studied population structure of testaceans of automorphic and hydromorphic soils in the middle taiga of Western Siberia. Rich testacean fauna has been revealed. The fauna representation was comparable to the studied soils of Ciscaucasian Russia. The bryophilic group was the most typical for the region, since its representatives inhabited the predominating hydromorphic soils of bogs. The typical species included Amphitrema flavum, Heleopera petricola, Placocista spinosa, Trigonopyxis arcula, Centropyxis laevigata, Nebela tincta, Arcella catinus, as well as other moss forms. Flood plain proved to be the richest by testacean species variability among the studied habitats. The set of species here included both representatives of watershed and typical aquatic forms present due to the flood conditions of a given area. The highest quantitative indices of the testacean complexes were revealed in the forest area soils. Quadrulella quadrigera Deflandre, 1936 found in a flood plain area has been revealed for the first time in Russia.