Adaptive evolution of primate mandibles across taxa: Diet and feeding ecology shapes the jaw.

Recent investigations into the functional link between diet and form have focused on rigorous quantitative methods for describing shape using geometric morphometrics. I used geometric morphometric analysis to investigate primate mandibular shape with respect to four dietary categories: frugivores, folivores, ripe fruit specialists and the cooked food specialist. I used statistical shape analysis to evaluate the contribution of dietary composition and feeding ecology to jaw morphology compared to other factors (e.g. phylogeny). Twenty-eight landmark coordinates on 178 haplorhine mandibles of 9 different taxa were collected using a 3D Microscribe. Coordinates were superimposed using procrustes analysis and then analyzed using MorphoJ software analysis package. Landmark coordinate values were analyzed using two sets. The first set utilized all 28 landmarks to represent the overall shape of the mandible, whereas the second set used only landmark coordinates found along the corpus and symphysis. Canonical variate analysis (CVA), ANOVA and discriminant function analysis revealed significant variation between frugivores, folivores and cook food specialists with less variation between ripe fruit specialists and frugivores in both data sets. This study not only shows predictable relationships to dietary classifications but also adds to the hypothesis that our bodies are adapted to a diet of cooked food