Methods of geometric morphometrics have been used to study geographic and chronographic forms of variation in the shape of the upper third molar (M3) in the gray red-backed vole C. rufocanus, a petrophilic rodent specialized to mountain habitats in the Urals. It has been shown that sexual dimorphism in M3 shape increases in the direction from the Southern to the Polar Urals. In the Middle Urals, differences in M3 shape (more distinct in males than in females) have been revealed between samples taken in years of high and low abundance of the species, which are apparently conditioned by a switch in tooth morphogenesis. This is suggestive of change in the morphofunctional properties of teeth and in related trophic preferences of males and females, i.e., in the possibility for them to consume different spectra of food resources. The increase in M3 sexual dimorphism in the south–north direction and in low-mountain biotopes (not common for the species) is in agreement with Chernov’s compensation principle manifested at the intra- and interpopulation levels, as it helps to alleviate trophic competition between males and females. The phenotypic plasticity of teeth provides for population-cenotic stability of the species in climatically unfavorable years and in atypical biotopes and environmental conditions of the Polar Ural Mountains.

中文翻译：

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灰红背田鼠 (Craseomys rufocanus) 和 Yu.I. 的种群内和种群间牙学变异性 切尔诺夫补偿原理

几何形态计量学方法已被用于研究灰红背田鼠 C. rufocanus 上第三磨牙 (M3) 形状变化的地理和时间记录形式，这是一种专用于乌拉尔山区栖息地的嗜岩啮齿动物。已经表明 M3 形状的两性二态性在从南部到极地乌拉尔的方向上增加。在中乌拉尔地区，M3 形状的差异（雄性比雌性更明显）在该物种高丰度和低丰度年份采集的样本之间已经显现出来，这显然是由牙齿形态发生的转换所决定的。这暗示了牙齿的形态功能特性以及雄性和雌性相关营养偏好的变化，即它们可能消耗不同种类的食物资源。南北方向和低山生物群落（该物种不常见）的 M3 性别二态性的增加与在种群内和种群间水平上表现出的切尔诺夫补偿原则一致，因为它有助于缓解雄性之间的营养竞争和女性。牙齿的表型可塑性为该物种在气候不利的年份和极地乌拉尔山脉的非典型生物群落和环境条件下提供了种群的稳定性。