Identifying the Influence of Artificial Neurocranial Deformation on Craniofacial Dimensions

Abstract

When the normal shape of a neurocranium has been altered by cranial deformation many craniofacial measurements can be affected. But, if those measurements less affected by such deformation are identified, they may then become useful in determining the phylogenetic positions of the populations in which artificial neurocranial deformation had been practiced. Univariate comparisons in means between undeformed and deformed skull groups in three American Native populations and the principal component analyses of direct associations between craniofacial measurements and the degree of neurocranial deformation showed that some of the craniofacial measurements are particularly strongly influenced by neurocranial deformation. As a result of excluding such measurements, five sets of craniofacial measurements relatively free of deformation were obtained for the classification of an Australian Pleistocene sample from Coobool Creek. The Mahalanobis' D² distances between the undeformed and deformed skull groups in Coobool Creek estimated using the five sets of variables are not significantly different from zero. The typicality probabilities calculated using the three sets of variables showing the highest probabilities for the null hypothesis of D² show that Keilor, an Australian Pleistocene individual, belongs to the Coobool Creek population, containing both undeformed and deformed individuals, at the typicality probability of 0.62 to 0.80. If the variables significantly or relatively strongly affected by deformation are excluded from the sets of variables to be used, the sets of remaining variables may be used to reasonably classify the relevant populations.