1Interdepartmental Doctoral Program in Anthropological Sciences, Stony Brook University, 2Department of Anthropology, Stony Brook University
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The dentition and maxillae are abundant in the hominin fossil record and have many important morphological and metric characteristics that are used to identify species. For example, Homo sapiens is distinguished from nonhuman primates and other hominin species by a smaller anterior dentition and reduced subnasal prognathism while some species of Paranthropus share a distinct suite of cranio-dental traits. In addition to their use in taxonomy, these traits are frequently treated as independent characters in phylogenetic analysis. However, facial and dental morphology may be developmentally correlated, and therefore not independent. This study analyzed how the size and shape of the face and palate covaried with the maxillary dental roots to determine the extent to which the face and dentition are morphologically integrated as a functional unit. First, we analyzed linear dimensions of Pan, Pongo, Gorilla and Homo crania measured from CT scans. Two-block partial least squares analysis was used to explore the covariation between dimensions of the maxillary dentition and the face. The results indicated dimensions of the face and dentition exhibit a similar magnitude and pattern of covariation across taxa, although the facial size dimensions had a stronger pattern of covariation with the dental variables than did those representing facial shape. Specimens with larger anterior dentition had larger faces that were broader and more protruding. These interspecific results will be compared to intraspecific analyses within P. troglodytes and H. sapiens. This study has implications for phylogenetic analyses and for understanding how dental development influences facial morphology.