Abstract
Abstract only Primate evolutionary and comparative studies often rely on an understanding of scaling patterns in the primate masticatory complex. Recently, it was proposed that molar root size predicts masticatory loading and molar crown size predicts facial size. We hypothesize that root surface area (RSA) scales isometrically with mandibular strength, and crown surface area (CSA) scales isometrically with facial size. CT scans of Macaca (n=19) and Papio (n=18) were used to calculate M 1 RSA, CSA and facial size (geometric mean of 9 linear distances). Mandibular strength (Zx) was calculated posterior to M 1 . RMA regressions were used to test scaling patterns among these properties. RSA was significantly correlated with Zx (r=0.76 and 0.69), exhibiting similar slope trajectories (p=0.182) in both species. Macaca scaled with isometry, however Papio was negatively isometric. RSA and facial size scaled isometrically in both taxa with similar slopes and elevations. In contrast, CSA displayed divergent scaling patterns relative to both Zx and facial size. For both variables, Papio possessed a significantly greater CSA slope trajectory. CSA scales isometrically with Zx and facial size in Papio , but with negative isometry in Macaca . Results partially support our hypotheses yet indicate that unique species‐specific scaling relationships exist for CSA and suggest that future studies should control for phylogenetic signals. Grant Funding Source : NIDCR (R03‐ DE019816 )