Department of Pathology and Anatomical Sciences, University of Missouri
Friday All day, Park Concourse
Recent experimental research has demonstrated that restricted growth along the zygomaxillary suture results in profound alteration of both the course of the zygomaxillary suture and overall facial morphology (especially facial projection and infraorbital surface topography). Given the potential evolutionary implications of a relationship between the zygomaxillary suture and overall facial morphology, it is currently necessary to more rigorously evaluate zygomaxillary suture morphology in both recent and fossil Homo. In this study, nine semilandmarks derived from a ridge-curve traced along the external surface of zygomaxillary suture were employed as a proxy for the course of the sutural plane. These semilandmarks were collected on a large sample of fossil (n = 58) and recent humans (n = 335). A subsequent principal components analysis reveals that the first three principal components account for 71% of the total sample variation. Cumulatively, these three components reveal that among the modern human sample, the greatest degree of variation exists between individuals from the Arctic Circle (straighter and more orthogonal sutures) and individuals from Africa and aboriginal Australia (more curved and parasagittally-oriented sutures). Among the fossils, Neandertals exhibit a considerable range of variation, with Early Neandertals (e.g. Saccopastore 2) appearing morphologically similar to Middle Pleistocene specimens such as Bodo and Petralona. Conversely, later Neandertals (e.g. La Chapelle-aux-Saints 1) exhibit markedly shorter, wider and more parasagittally-oriented sutures. These preliminary results further suggest that the zygomaxillary suture may be important for understanding shifts in craniofacial form during human evolution.
This research was supported by grants from the Wenner-Gren Foundation, Leakey Foundation, and the University of Iowa.