Analysis of the structure of the morphological diversity of the Altai osmans of the genus Oreoleuciscus in the Urt River (water system of the Tes River) indicates that this is a polymorphic population, consisting of three forms, clearly differentiated by a set of characters. The ratio of differences between these forms and forms previously identified in the Zavkhan (water system of the Great Lakes Hollow) and Tuin (water system of the Lake Valley) rivers suggests that the characters considered in the study are adaptively plastic, and the revealed structure of the morphological diversity of the genus is mostly determined by local patterns of environmental conditions.