No abstract

Objectives: Although the homology of the Neanderthal occipital bun and anatomically modern human "hemi-bun" has long been debated, little is known about the developmental timing and patterning of these two patterns of prominent occipital squama convexity. In this study, occipital hemi-bun ontogeny and cranial shape covariation are assessed in a comparative extant human sample.Materials and Methods: Two-dimensional geometric morphometric methods were used to investigate hemi-bun development in a longitudinal sample of growth study cephalograms representing extant human subjects predominantly of European ancestry. Subjects were each measured at three distinct age points, ranging from 3.0 to 20.4 years, and two-block partial least squares analysis was used to assess patterns of covariation between midsagittal occipital bone morphology and other aspects of craniofacial shape.Results: Occipital hemi-bun morphology, when present, was found to develop early in ontogeny, in association with anteroposterior elongation of the frontal and parietal bones. No significant pattern of covariation was found between occipital hemi-bun shape and cranial/basicranial breadth, basicranial length, basicranial angle, or midfacial prognathism.Discussion: This study suggests that the occipital hemi-bun, at least in this extant human population, should not be considered an independent trait, as its development is closely linked to shape variation in the frontal and parietal bones. Importantly, these results suggest that occipital hemi-bun morphology is not significantly influenced by basicranial morphology during development, but instead covaries with changes in midsagittal neurocranial vault shape. K E Y W O R D S chignon, cranial development, occipital bun, ontogeny, shape covariation

I would also like to acknowledge my fellow graduate students at The University of Iowa, all of whom have shaped my work and provided valuable guidance and moral support over the past five years. I would specifically like to thank Dr. Christina Nicholas for her wise advice and friendship. Thank you to my fellow "Guilt Guild" members, Meredith Wismer-Lanoë, Shelby Putt, and Teddy Marks, for providing accountability during my last semester of dissertation writing. And finally, I would like to thank my family and friends for their patience, love, and encouragement during my graduate education. Thank you to my grandmother, Martha Scharfenberg, and my uncle, Chuck Scharfenberg, for instilling in me the desire to learn and the stubbornness to make it through graduate school. I would also like to thank my sister, Megan Boveri, for her brilliant writing suggestions. And last, but certainly not least, I would like to thank my husband John for believing in me during my weakest moments, for encouraging me to do my best, and for helping me stay grounded.