1Division of Basic Medical Sciences, Mercer University School of Medicine, 2Department of Anthropology, University at Albany, 3Department of Biology, Mercer University
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Craniofacial sutures are weak points compared to rigid bone on the skull thence they must be shielded from unduly high stresses so as not to disrupt vital growth processes and skeletal functions. Thus, it is hypothesized that the placement of sutures should maximize their growth potentials yet minimize their negative biomechanical impacts, especially in areas under high stress during dietary activities, such as the midface. Specifically, for any given suture, it is hypothesized that suture position would be different in skulls of different form adapted to different dietary ecology. In this study, we investigated the position of the Maxillo-Zygomatic suture (MZS) in five species of Old World Monkeys (OWM) and six species of New World Monkeys (NWM) by calculating the relative Zygoma breadth compared to the facial breadth at the level of the inferior rim of the orbit. Results demonstrated that the ZMS in NWM has a more lateral position compared to that in OWM. Consequently, the ratio of facial surface vs. temporal surface of the Zygoma in NWM is relatively smaller than that in OWM, which is coupled with different configuration patterns in the orbital and pterion areas. Variation is also present within closely related taxa. For example, the ZMS is more laterally placed in Cebus apella than in C. albifrons. These findings suggest different bone interaction patterns related to differences in dietary ecology. The significance of the placement of sutures thus warrants careful ontogenetic, phylogenetic, and biomechanical studies.
Supported by NSF HOMINID BCS-0725126, BCS-0725183.