3D geometric morphometric study of cranial deformation in medieval Nesef

Abstract

Introduction. Skulls from the medieval necropolis Shulluktepa (Nesef, XI-XII centuries) were previously studied using 2D geometric morphometrics. Based on the analysis of the sagittal contour, two types of artificial cranial deformation were identified. These types could be associated with different populations gathering in this urban center of Southern Sogdiana. We observed that samples with different types of deformation could be clearly distinguished, while undeformed skulls differ from slightly deformed insignificantly. 3D models and the landmark’s placement algorithm we have developed allow us to utilize these materials again.

Materials and methods. 3D models of skulls from Shulluktepa (MAE No. 7275) were studied using geometric morphometrics. The sample included 44 male and 42 female skulls. The types of deformation were analyzed through processing the landmark’s coordinates within a triangular patch between craniometric points (bregma, left and right asterions). The surface of this patch was automatically filled with semilandmarks. The comparison was carried out using generalized Procrustes analysis, Principal component analysis and canonical analysis realized in R-Studio.

Results and discussion. Based on the analysis results artificially deformed skulls were divided into two types of cranial deformation — parietal and occipital. 3D methods, unlike 2D, allowed us to identify undeformed skulls. There are no differences between males and females in case of parietal deformation, but occipital deformation is more pronounced in males. Comparison of the viscerocranium and neurocranium variability confirmed their independence. There is no influence of interpopulation differences on the results of the neurocrania shape study.

Conclusion. The presence of two types of artificial cranial deformation in the group was proved. It was shown that a triangular patch is more advantageous for the study of artificial deformation than analysis of 2D sagittal contours. Results of the comparison of viscerocranium and neurocranium variability can be used to verify the possible influence of interpopulation differences.

Funding. The research was carried out with the support of grant Russian Scientific Found No. 25-28-01027 "Artificial deformation of the human skull in ancient and near-modern populations: a study by methods of two-dimensional and three- dimensional geometric morphometry”.

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