Functional and phylogenetic variation in anthropoid incisor size.

Although both ratios support a link between incisor size and diet, there is some evidence indicating that mandible-based ratios are more sensitive to dietary variation at smaller phylogenetic scales. Understanding why the signals from the two ratios diverge at such scales may help clarify the functional significance of variation in incisor width. The results of this study undermine the view that platyrrhines, as a group, tend to have narrower incisors than catarrhines, regardless of diet. Instead, the difference between the two clades noted in previous studies can be explained by greater incisor functional diversity in platyrrhines.