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the previous studies of Euro-American and African-American samples ( Wescott and Jantz,
2005 ), the confounding variables were more easily controlled. The authors tested two hypoth-
eses found in previous studies: (1) cranial morphology will change as a result of demographic
transitions (population growth, urbanization, etc.) and (2) allometry will have a localized
effect on cranial shape, specifically in areas of variation found to be important in growth
and development.
They tested these hypotheses by using geometric morphometrics on 67 cranial landmarks,
and dividing the series into an ontogenetic (subadult) series and an adult series. Multiple
regression on the symmetric components of the Procrustes coordinates on year of birth
and Centroid Size were used to examine shape change over time and examine patterns of
allometry. The sample was further divided by sex into 25-year birth cohorts to assess the rela-
tive position of the birth cohorts in the multivariate analyses. A secular trend was indicated
by the chronological ordering of birth cohorts in the data as detected in CVA. The multiple
regression of shape on year of birth in the sample indicates a strong and statistically signif-
icant temporal change over the last 150 years. The changes that occurred during this time
period in Portugal were mostly to the cranial base, a region of the skull that experiences
an early growth curve. Weisensee and Jantz (2011) argued that this change was most likely
associated with declines in childhood morbidity and mortality.
Forensic Anthropology
The use of geometric morphometrics within the field of forensic anthropology is varied,
and includes methods for sex estimation and ancestry analyses. The following are just
a few examples of the use of geometric morphometrics in the field over the last decade or so.
In an early attempt at using geometric morphometrics to differentiate groups based on
craniofacial morphology, Ross et al. (1999) compared a sample of Euro-Americans and
African Americans to test for differential morphological patterns. A total of 14 cranial land-
marks was recorded. After Procustes superimposition, the crania were subjected to discrim-
inant analysis. This early study was successful in the classification of crania and
demonstrated how these methods could be employed as a tool to locate specific regions of
morphological variation important to distinguishing between groups.
Similar to the estimation of sex in subadult skeletal material, the estimation of ancestry is
equally difficult. Buck and Strand Viðarsd ´ ttir (2004) analyzed mandibular morphology for
ancestral estimation as skeletal remains in forensic cases are often found incomplete. Their
study sample represented five distinct morphological groups and included both adult and
subadult mandibles. Seventeen unilateral landmarks were digitized on the mandibular ramus
and corpus. Coordinate data were subjected to Procrustes superimposition. PCA of the fitted
coordinates was used to account for the principal axes of variation within the sample and
discriminant analysis was applied to the data in order to classify individuals. Their results
show that significant classification is achieved for the completemandible (
70%), with slightly
less accurate classification results for incomplete mandibular remains. The results suggest that
mandibular shape might be useful in the estimation of ancestry in subadult skeletal material.
Using facial contours, Sholts et al. (2011b) examined the midfacial skeleton in modern
human groups, as this region of the skull has been found to have higher predictive value
for group classification. They analyzed the midfacial skeleton employing digital scans of
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