Department of Anthropology, University of Iowa
Friday All day, Clinch Concourse
The mid-face of extant H. sapiens is known to undergo shape changes through fetal and neo-natal ontogeny; however, little work has been done to quantify these shape changes. Further, while mid-facial traits which vary in frequency between populations of extant humans are presumed to develop prenatally, patterns of populational variation maxillary shape across ontogeny are not well documented. Only one study has taken a 3D geometric morphometric approach to studying prenatal maxillary ontogeny, and that study was limited to one population (Japanese). The present research project seeks to augment our understanding of fetal maxillary growth patterns, most especially in terms of intraspecific variation. The primary hypothesis tested is whether fetal maxillary dimensions can accurately predict ancestry. 3D coordinate landmark data was taken on the right maxillae of 80 fetal and neo-natal individuals from three groups (Euro-American, African-American, “Mixed Ancestry”) using an Immersion Corp. Digital Microscribe. Data were analyzed using regression, principle components analysis (PCA), and canonical variates analysis (CVA) using the programs Morphologika and MorphoJ. Shape changes were seen mainly in the lateral wall of the piriform aperture, the anterior nasal spine, and the anterior alveolar region. Specimens did not cluster distinctly by age in the CVA. However, the Euro-Americans and African-Americans did cluster by population with only modest overlap, indicating that populational variation in maxillary morphology appears very early in ontogeny. The mid-face is a critical region of the skull for assessing ancestry, and these results indicate that maxillary dimensions may be useful for estimating ancestry for prenatal individuals.