Four new species of the mite genus Bakerdania (Heterostigmata, Pygmephoridae) from Russia

Four new mite species (Bakerdania palustris, B. taymyrica, B. mycophila, and B. littoralis) from different regions of Russia are described. Bakerdania palustris sp. n. is most similar to B. janetscheki Mahunka, 1970, differing in the presence of adjoining bases of setae ps ₂ and ps ₃ (in B. janetscheki, ps ₃ is separated from ps ₂) and also by shorter smooth setae 2b (in B. janetscheki, setae 2b are serrate and distinctly longer). Bakerdania taymyrica sp. n. is most similar to B. heisseli Mahunka, 1970, differing in the presence of the brush-like setae 1a (that are trichoid and serrate in B. heisseli); shorter setae tc′ on the tibiotarsus I, that are almost half as long as setae pl′ (in B. heisseli, tc′ is much longer, nearly as long as pl′). Bakerdania mycophila sp. n. is most similar to B. racki (Mahunka, 1967), differing in the presence of significantly longer ventral setae and the separate solenidion ω₁ (in B. racki, the latter is fused with the tibiotarsus). Bakerdania littoralis sp. n. is most similar to B. racki, differing from the latter in the shape of setae 1a, 2a, 3a, 3b, 4a that are basally thickened; in the shape of setae ps ₁ (trichoid in B. racki); and in the presence of the non-furcated setae 1b (in B. racki, these setae are bifurcate).