A metric study of three types of artificial cranial modification from north‐central Peru

Artificial cranial modification (ACM) involves the alteration of cranial vault shape by cultural means, and is performed during infancy while the cranial bones remain soft and malleable. The direction of normal cranial growth is altered through the application of external forces. In this study, three types of ACM from north‐central Peru (posterior flattening, bilobed and circumferential) were analysed using standard craniometric techniques. The aim was to determine the effects of these forms of ACM on craniofacial morphology, and the extent to which different types of ACM could be distinguished from one another and unmodified crania on the basis of these measurements. Significant differences between artificially modified and unmodified crania, and between different types of ACM, were demonstrated in cranial vault shape for all types. Significant differences in facial morphology were found only in the bilobed group compared with the unmodified crania. Canonical variates analysis (discriminant analysis) confirmed that major differences between modification types and unmodified crania were in measurements and angles of the cranial vault. While the results show some similarities to previous studies, they add to the variability in the patterns and extent of differences documented to date. It is suggested, based on these results and visual observations, that interpopulation variation in ACM within major modification categories may explain some of the variability in results between studies, an explanation which has previously received insufficient recognition but which remains to be tested since varied methodology between studies may also be a contributory factor. While previous studies have often sought to generalise about the effects of ACM, the examination of the differences between populations even within major ACM categories may offer new insight into cultural variation in modification techniques between populations and the nature of craniofacial development. Copyright © 2009 John Wiley & Sons, Ltd.     

Boards and Cords: Discriminating Types of Artificial Cranial Deformation in Prehispanic South Central Andean Populations

For over a century, a number of ambiguous typologies have been employed to distinctly categorise types of artificial cranial deformation. This paper provides a quantitative method, based on multiple dimensions and discriminant function analysis, by which to assign skulls not only into discrete categories: deformed or not, but also by type: annular or tabular. A series of prehispanic, adult, human crania (n = 469) from archaeological sites in Argentina, Bolivia, Chile and Peru represented by both normal and artificially deformed specimens, provide craniometric data for four measurements across the vault: maximum cranial length, breadth and height and the frontal chord. These data are used to develop three indices which in turn are used to compute two discriminant functions. Results are plotted on a territorial map whereby the type of deformity can be determined. When these methods were applied to a comparative cranial sample of nondeformed skulls from South America, 100% of the samples was found to be nondeformed. When these methods were applied to the samples which were subjectively classified a priori by the first author as nondeformed, 81.3% of the samples were found to be nondeformed. This study demonstrates the value of a more objective and quantitative method by which to classify artificial cranial deformation, and thus provides a new approach. Copyright © 2011 John Wiley & Sons, Ltd.     

Comparison of coordinate measurement precision of different landmark types on human crania using a 3D laser scanner and a 3D digitiser: Implications for applications of digital morphometrics

A total of 11 340 Cartesian coordinates of 42 homologous landmarks on five excavated human crania were recorded by three observers using a three‐dimensional (3D) digitiser and computer models created with a 3D laser scanner. The aim was to compare the errors of the coordinate data of landmarks of different types recorded with these two techniques. The results showed that digitiser‐based and 3D model‐based coordinate measurements had overall standard deviations of, respectively, ±0.79 and ±1.05 mm. However, the 3D digitiser yielded the most precise coordinate data for landmarks defined primarily by biological criteria (Type I landmarks), while the 3D laser scanner models yielded the most precise coordinate data for landmarks defined primarily by geometric criteria (Type III landmarks). These findings are likely to influence the research design of future craniometric studies, as they indicate that the suitability of certain landmark types as reference points for geometric operations, such as partial Procrustes analysis, depends on the method by which they are measured. This information is particularly important for retrospective research or for combined databases such as FORDISC or CRANID, which may integrate different types of landmarks recorded by different researchers and/or instruments. Crania displaying poor preservation and surface discoloration yielded larger measurement errors, especially for the 3D model measurements. This is not surprising given that landmarks on 3D models cannot be located using tactile means, but have to be located solely on a visual basis. Nonetheless, even though the digitiser measurements exhibit an overall precision slightly greater than the 3D model measurements, both techniques yield coordinate data with a precision sufficient for most craniometric research. Copyright © 2010 John Wiley & Sons, Ltd.     

Past or present? Differentiating California prehistoric native American remains from forensic cases: An empirical approach

The goal of this project is to provide additional data and statistical analyses for differentiating between prehistoric/historic Native American remains and modern forensic cases that may be potentially confusing. Forensic anthropologists often receive requests from local law enforcement to infer whether skeletal remains are of forensic or non‐forensic significance. Skeletal remains of non‐forensic significance are commonly of Native American ancestry, but the empirical methods common for determining Native American affinity from skeletal remains have not been established for California prehistoric/historic Native Americans. Therefore, forensic anthropologists working in California lack empirical methods for not only identifying prehistoric California Native American remains, but also differentiating them from modern/forensic populations whose skeletal attributes are similar. In particular, skeletal remains of Latin American US immigrants of indigenous origins are becoming more present in the forensic anthropological laboratory, and can exhibit the same suite of skeletal traits classically used to identify Native American affinity. In this article, we initiate an investigation into this issue by analyzing both craniometric and morphoscopic data using a range of statistical methods for differentiating prehistoric Northern California Native Americans from modern Guatemalan Maya. Our discriminant analyses results indicate that by using nine craniometric variables, group classification is 87% correct. In addition, seven morphoscopic variables can predict group classification correctly for 77% of the sample. The results suggest that it is possible to differentiate between our two samples. Such a method contributes to the efficient and empirical determination of temporal and geographic affinity, allowing for the repartriation of Native American remains to their tribes, as well as the accurate analysis of forensically significant remains. Copyright © 2010 John Wiley & Sons, Ltd.     

A Geometric Morphometric Study of Regional Craniofacial Variation in Mexico

Spanish speaking populations in the USA have long been categorised under the umbrella term ‘Hispanic’, which is a cultural construct. The term Hispanic ignores the unique ethnohistories and biological variation among Hispanic groups with various European, African and indigenous American influences. Considerable heterogeneity has been identified in pre‐contact America and has continued to influence the cultural and biological compositions of various regions today. The purpose of this research is to examine biological variation in Mexico, which was influenced by indigenous migration patterns and the Old World conquests of the Americans. Using multivariate statistics, this paper compares 16 three‐dimensional craniometric landmarks of samples from northern Central Mexico, northern Yucatan and western Mexico to examine the regional biological variation present in Mexico in both prehistoric and historic groups and also compares Mexican, Spanish and African American groups to examine patterns of Old World conquests. Multivariate statistics detected significant group differences for both size and shape (centroid size, p < 0.0001; shape, p < 0.0001) and showed that while significantly different, all the Mexican groups are more similar to one another except for one prehistoric inland‐western Mexican group, which is morphologically distinct from the other Mexican groups. Previous mtDNA research in these areas shows a low prevalence of African American admixture and a high indigenous component in the northern Mexican groups, which is consistent with the findings of this paper. The prehistoric and historic Mexican groups were the most similar indicating the retention of indigenous admixture after contact. The results from this analysis demonstrate that all groups are significantly different from one another supporting other findings that have shown that the indigenous populations of the New World are heterogeneous and that this variation may also contribute to the heterogeneity of contemporary populations. Copyright © 2013 John Wiley & Sons, Ltd.