Kartavtseva I. V., *, Pozdnyakov A. A.,, Stepanova A. I., Sheremetyeva I. N., Pavlenko M. V.
Biology Bulletin 2026; 53: 101
The Evoron vole is a narrow-range species known from isolated populations of three mountain basins in the south of the Russian Far East. The species has a multiple chromosomal polymorphism, detected in two chromosomal races (“Evoron” and “Argy”). Morphotypic variability of the surface pattern of 357 third upper molars (M3) was analyzed in voles from six natural samples (Evoron-Chukchagir Lowland, 2; Verkhne-Bureinskaya Depression, 1; Verkhne-Zeya Basin, 2; and upper reaches of the Amgun River, 1), as well as three groups of laboratory breeding of chromosomal races. The traditional and complex methods were used to isolate the morphotypes. Using the complex method, 16 morphotypes were isolated, ten of which were not previously described for this species. Each sample was characterized by its own set of the main morphotypes. The number of reserve morphotypes in natural samples was lower (from 0 to 5) than in laboratory groups (from 5 to 10). In individuals of the chromosomal race “Evoron” (samples from the Evoron-Chukchagir Lowland), M3 morphotypes with fused first two prisms, as well as lower morphotypic variability as compared to the “Argy” chromosomal race (samples from the Verkhne-Bureinskaya Depression and Verkhne- Zeya Basin), were identified using the complex method. It was also demonstrated that the chromosomal races have differences in the number of morphotypes, asymmetry index, and frequency of their combinations. A comparison of M3 complexity coefficients in two groups of all samples taken at different times in the 1970s and 2000s from three intermountain basins allowed us to identify a chronographic trend of an increase in the portion of simple teeth in a forty-year study interval.
