Variants of tooth mesowear in Microtus voles as indicators of food hardness and abrasiveness

Methodological approaches to the description of variants and degrees of hypselodont tooth mesowear in voles are proposed on the basis of studies on the collection of skulls of two vole species trapped in the field (narrow-headed vole, n = 38; common vole, n = 22) and two species from laboratory colonies (narrow-headed vole, n = 46; root vole, n = 76). Trends in the manifestation of different mesowear variants have been analyzed in experiments on feeding root voles from the laboratory colony with “hard” and “soft” foods. It has been found that animals kept on low-abrasive diet show signs of wear due to tooth-to-tooth contact, such as low crown height, relatively obtuse wear angle and more upright position of m/1 in the jaw, shallow occlusal surface relief, and lateral wear facets. Chewing hard food items requires application of vertical occlusal pressure, which result in the formation of a depression in repair dentin, while denser dentin at the anterior enamel wall of prisms remains unworn.