Two new water mite species of the genus Atractides (Acariformes,Hygrobatidae) from the Northern Caucasus

An illustrated description of two new water mite species of the genus Atractides (male, female, and larvae of A. expansipalpis and male of A. caucasicus) is given. The adult mites of the first species are characterized by the following features: setae Fch thick and relatively short, pedipalpal femur without ventrodistal tubercle; pedipalpal tibia strongly thickened, with convex ventral margin; genital plate almost circular in male (length to width ratio 0.96–1.00); genital plates elongate in female (length to width ratio 3.2–3.7); and dorsal shield of larva with 5 pairs of setae. The male of A. caucasicus sp. n. is similar to that of A. expansipalpis but differs from it in the following characters (characters of A. expansipalpis are shown in parentheses): setae Fch long and thin (short and thick), pedipalpal femur with ventrodistal tubercle and hyaline projection (without ventrodistal tubercle and hyaline projection), posterior margin of genital plate convex (concave). Both species were collected in the Ubin River of Krasnodar Territory (the Northern Caucasus, Russia).