| abstract | This work deals with five species of oribatid mites from Trans-Altai Gobi, Mongolia. Mainothrus transaltaicus sp. n. is proposed on the basis of adults, deuto- and tritonymphs, and a diagnostic key to adults of all known species of Mainothrus is presented. Ramusella samiyai sp. n. is proposed based on adults, which assigned to the subgenus Insculptoppia Subías, 1980. Passalozetes africanus Grandjean, 1932 is newly recorded in Mongolia, and two other species, Atropacarus striculus (C.L. Koch, 1836) and Tectocepheus alatus Berlese, 1913 are reported for the first time from Trans-Altai Gobi. Following the descriptions and comparisons, we discuss aspects of the distribution and habitat ecology of these species. |