Abstract
The present study is based on oribatid mite material collected from Altai Krai and Altai Republic, southern part of Western Siberia, Russia. A list of 60 species, belonging to 51 genera and 29 families, is presented; of these, two species (Moritzoppia metulifera, Zachvatkinibates latilamellatus) are recorded for the first time in Russia; one new species -Sphaerozetes parafirthensis Ermilov n. sp.- is described from soil and moss collected in the Kosh-Agachsky District, Altai Republic. The new species differs from the closely related species, Sphaerozetes firthensis by the larger body size, narrowly lanceolate bothridial seta, strong lateral tooth on lamellar cusp, and broadly oval postanal porose area. An identification key to representatives of this genus from the Palaearctic region is provided.