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Human Craniofacial Ontogeny

Dr. Gary D. Richards

In the past, research on the skull and dentition relied on measurements of actual specimens. Today this work is being augmented at a rapidly increasing rate by research done on images of specimens. Recent advances in computed tomography and magnetic resonance imaging are allowing imaging at a submicron scale with very high resolutions. Further, computerized representations of these specimens are based on 3D meshes (triangles, tetrahedrals). Meshes not only allow for visual representation of the object, via isosurfaces or volume renderings, but they provide the basis from which to analyze shape and shape change by employing finite-element, thin-plate spline, and eigenvector analyses. Whereas these technologies unlock significant new areas of research, understanding how one's results relate to biological reality is an ongoing problem.

I am both testing and employing a range of imaging sources in my research on human ontogeny and evolution. Currently, we are expending significant effort in our quest to image histological details of teeth with synchrotron microCT. We are working closely with beamline scientists at the Advanced Light Source, Lawrence Berkeley National Laboratory in this effort. Additionally, I hope to begin incorporating newly developed high resolution MRI into my research later this year.

Current projects:

Computed tomography-based investigations of cranial evolution in Middle to Late Pleistocene cave bears from Europe and Middle Pleistocene hyaenas from Africa. Research in collaboration with investigators from the Laboratorio de Evolución Humana, Dpto. de Ciencias Históricas y Geografía, Universidad de Burgos, Spain.

Computed tomography-based investigation of modern human semicircular canals. In collaboration with investigators at the Human Evolution Research Center, UC Berkeley, the National Museum of Ethiopia, and the University of Zurich.

Current publications:

"Color centers induced in dental enamel during synchrotron microcomputed tomography: phase I assessment". Caroline F. Horton, Gary D. Richards, Tim D. White, Alastair MacDowell, Rebecca S. Jabbour, and James Nasiatka. 2010. Am. J. Phys. Anthropol. 44 (Suppl):

"Color centers induced in dental enamel during synchrotron microcomputed tomography". Gary D. Richards, Caroline F. Horton, Alastair MacDowell, Caitlin L. Ibarra, Rebecca S. Jabbour, James Nasiatka, and Tim D. White. Manuscript in preparation for the Am. J. Phy. Anthropol.

Contact:

Dr. Gary D. Richards, grichard@pacific.edu, 415.929.6573