Alexandromys evoronensis, (Kovalskaya et Sokolov, 1980) (Kovalskaya et Sokolov, 1980)

Kartavtseva, Irina V., Stepanova, Anastasia I., Sheremetyeva, Irina N., Pavlenko, Marina V. & Frisman, Liubov V., 2023, A new record of the Evoron vole (Rodentia, Arvicolinae: Alexandromys evoronensis) in the Far East, Amurian Zoological Journal XV (2), pp. 378-384 : 382-383

Results and discussion

The karyotype with 2n = 36, NF = 56 ( Fig. 1 : D) contains 18 biarmed and 16 acrocentric autosomes. The X chromosome is a medium-sized submetacentric. This karyotype corresponds to the Evoron vole of the Argi race ( Kartavtseva et al. 2021a). Chromosome numbers are assigned according to the previously published data for voles with 36 chromosomes: karyotype 2n = 36b. Without differential staining of chromosomes, we cannot confidently state which chromosomes underwent structural rearrangements and the type of these rearrangements.

Body measurements of the Evoron vole from four populations (Table 2 and Fig. 2 ) show two groupings. The first group includes populations I and III, the second populations II and IV. Population IV studied by us for the first time is similar to population II. The Tyrma and Urgal rivers (population II) originate in the southwestern slopes of the Bureinsky Range and flow into the Bureya River ( Fig. 1 : A). In the lower reaches, the Tyrma River makes a sharp bend, inside which swampy lowlands overgrown with grass and tussock meadows with small areas of broad-leaved forests predominate ( Fig. 1 : B). Both populations (II and IV) are located in the western spurs of the Bureinsky Range. These populations may have a common origin.

However, drawing the conclusion about the similarity of populations with those studied previously requires further morphological and genetic investigation. Karyotyping of one female (2n = 36) revealed a similarity with the Argi chromosomal race of the A. evoronensis (karyotype 36 = 36b) from populations II and III. The new records of voles in the Tyrma River valley expand the range of Evoron vole and indicates more southerly habitats than previously stated.

Figures

Рис. 1. Карта мест сбора, внешний виÀ Alexandromys evoronensis и кариотип. (A) Черные кружки соответствуют хромосомной расе «Эворон»; черные звезÀочки — хромосомной расе «Арги» (Kartavtseva et al. 2021a; 2021b). ПопуΑяции, распоΑоженные в межгорных районах юга ΔаΑьнего Востока России: I — Эворон-Чукчагирская низменность; II — Верхнебуреинская впаÀина; III — Верхнезейская равнина. РяÀы пунктирных Αиний обозначают горные хребты. (B) — забоΑоченная низменность поросшая разнотравьем, Àерновые Αуга с небоΑьшими участками широкоΑиственных Αесов ÀоΑины р. Тырма, 7 августа 2022 г. (С) Фотография эворонской поΑевки (№ 4700 ♀). (D) Кариотип эворонской поΑевки (№ 4700 ♀): 2n = 36, NF = 56, M-Sm – метацентрики-субметецентрики, А — акроцентрики, С — хромосомы разной морфоΑогии, образованные в резуΑьтате сΑияния акроцентрических хромосом Àвумя типами: центромера-центромера (13.15, 17.18) и центромера-теΑомера (11/19). Fig. 1. The map of the collection localities, appearance of the Alexandromys evoronensis and its karyotype. (A) Black circles correspond to the Evoron chromosomal race; black stars to the Argi chromosomal race (Kartavtseva et al. 2021a; 2021b). Populations located in the intermontane regions of the south of the Far East: I — Evoron- Chukchagirskaya Lowland; II — Verkhnebureinskaya Depression; III — Verkhnezeiskaya Plain. Rows of dotted lines indicate mountain ranges. (B) The swampy lowland overgrown with grass, sod meadows with small areas of broad-leaved forests of the Tyrma River valley, August 7, 2022. (С) An image of Evoron vole (No 4700 ♀). (D) The karyotype of Evoron vole (No 4700): 2n = 36, NF = 56, M-Sm — metacentrics-submetecenrtics, A — acrocentrics, C — chromosomes of different morphology formed as a result of fusion of acrocentric chromosomes of two types: centromere-centromere (13.15, 17.18) and centromere-telomere (11/19)

Рис. 2. КΑассификация выборок (I – IV) Alexandromys evoronensis по Àанным промеров теΑа метоÀом UPGMA. Fig. 2.Classification of Alexandromysevoronensis (I – IV) usingUPGMA body measurements (given in Euclidean distances)