Ontogenetic variation in occlusal shape of evergrowing molars in voles: An intravital study in Microtus gregalis (Arvicolinae,Rodentia)

In order to reveal patterns of ontogenetic change in occlusal shape of evergrowing molars in arvicolines, an intravital tooth printing method was applied to 20 individuals of Microtus gregalis born in captivity. Complexity patterns of the first lower molar were assessed by morphotype analysis of the anteroconid complex. Morphotype dental patterns were monitored using tooth prints at 0.5, 1, 2, 3 months of age, and postmortem. Ontogenetic changes in molar complexity and bilateral symmetry among right and left molars of the same individual during the process of tooth wear were assessed. Our results suggested that morphotype dental patterns could not be clearly established in half-month old animals due to presence of juvenile characters. For animals of 1 month and older, age differences in morphotype dental patterns were non-significant and negligible compared to among-individual variation. Within-individual differences among right and left molars, when present, were not related to age of an animal suggesting that bilateral asymmetry of morphotype dental pattern could be regarded as inherent characteristic of an individual persisting during post-juvenile tooth wear.