Dental enamel ultrastructure in ochotona and prolagus (Mammalia: Lagomorpha: Ochotonidae) from three late miocene localities in Ukraine

Abstract

The comparison of the dental enamel of late Miocene ochotonids from the Ukraine shows only very subtle differences. The ultrastructure of premolars, molars, and incisors of pikas: Ochotona and Prolagus (Lagomorpha, Ochotonidae) from three localities (Popovo 3, MN 11; Verkhnya Krynytsya 2, MN 12; Lobkove, MN 12/13) is mainly multilayered. In cheek teeth it is composed of a radial (up to 60% of total enamel thickness) and an irregular layer (up to 40%). There is almost no difference in the enamel ultrastructure between remains of different geological age and tooth position (premolars, molars). However, the lower incisor of Ochotona differs from the upper one in having a radial enamel and a HSB layer, whereas the upper have a radial and a tangential enamel. Minor differences between the various species of Ochotona and Prolagus could be recognised in the arrangement of the prisms.