UNIFICATION OF THE CRITERIA FOR DISTINGUISHING THE CHEEK TEETH MORPHOTYPES IN LEMMINGS (LEMMINI, ARVICOLINAE, RODENTIA)

摘要

The paper summarizes data on morphotype dental patterns in recent lemmings (Lemmini) and their earliest presumed ancestors as obtained based on an analysis both of existing literature and zoological collections. The criteria for distinguishing the morphotypes are unified and four metrics are proposed to assess 1) the occlusal surface complexity, 2) the regularity of enamel cutting edges, 3) the asymmetry of lingual and buccal prisms, and 4) the degree of cement deposition at reentrant angles. A catalogue of basic, reserve and rare morphotypes is created for Lemmus sibiricus and Myopus schisticolor. The approach developed here is recommended for further research in spatial, temporal, and ontogenetic variations in Lemmini, based on their dental characters.