Morphological integration of the human mandible in two pre‐ Columbian skeletal samples

Abstract

The human skull is a complex structure composed of many semi‐independent but integrated units. Functionally, the cranium is often partitioned into three modules: the vault, basicranium, and splanchnocranium. While the mandible is an integral functional component of the skull, it is rarely examined in the field of human morphological integration. In this study, we investigate patterns of integration between the vault, basicranium, and mandible in adult skulls from two related pre‐Columbian populations—Caddo and Arikara—using 3D geometric morphometrics. The Caddo exhibit artificial cranial deformation (ACD), while the Arikara are nondeformed (ND). This study tests two null hypotheses: (1) ACD skulls will demonstrate the same levels of overall integration as ND skulls, and (2) patterns of integration between the mandible and cranial base are not affected by ACD. Procrustes superimposition is used to scale and rotate the coordinate data, and principal component analysis and discriminant function analysis are used to assess shape differences and variation between the samples. Results indicate that integrated shape changes are complex, but the overall pattern is similar among the ACD and ND samples. This is one of the first studies to examine how patterns of integration between the mandibule and other modules of the cranium are affected by ACD.Grant Funding Source: AAA