Functional anatomy of bovid upper molar occlusal surfaces with respect to diet

Abstract

This paper presents an analysis of molar occlusal morphology and its relation to diet in modern bovids. The work develops previous research by analysing samples from 86 species from all major subfamilies and from across their geographical distribution. Molar surfaces are characterized by the length, thickness and shape of enamel formations. Discriminant function analysis (DFA) is used to characterize the dental anatomy of each group and permits interpretations as to the selective pressures governing occlusal form. Grazers and most browsers are very different and distinguishable, the former possessing long and thickened enamel with a bimodal distribution of central ridge enamel alignment. Frugivorous duikers possess thickened enamel and large surface areas, traits interpreted as adaptations for hard-object feeding. Mixed feeders consuming mostly dicot material cluster with browsers, while mixed-grazers approach but do not attain a grazer-like morphology. Many browser-like characteristics are present in mixed feeders that consume significant proportions of grass. Plant toughness is seen as a primary driver of occlusal form in bovids. A greater variation in occlusal form between and within feeding groups is observed compared with that noted previously. Finally, the use of DFA renders the application of occlusal morphology as a means of inferring dietary ecology in extinct forms a distinct possibility.