Revisiting historical Khoe-San skeletal remains in European collections: A search for identity through craniometric analysis.

As the identity of a large number of Khoe-San skeletal material in European collections recently came into question during its documentation, a re-evaluation of the remains by employing a non-invasive method such as craniometrics was done to investigate the biological affinity. For this purpose, gene flow and population diversity present within the group, as well as between the study sample (N=63) and other modern and historic population groups from southern, central and east Africa were explored. Available comparative groups included the historic Khoe-San from Riet River (N=31), the Sotho-Tswana from southern Africa (N=61), the Basuku from central Africa (N=66) and the Bahutu (N=53) and Teita (N=24) from east Africa. Ten craniometric variables were selected and used to perform population structure analysis based on model bound quantitative genetics and multiple discriminant function analysis (MDA). Quantitative genetic distances revealed that the Khoe-San sample was closest to the Riet River group. Residual variance analysis performed on two-sample subsets of the Khoe-San group (Cape KS and Various KS) showed a higher level of heterogeneity in the Cape KS than seen in the Khoe-San from various other areas in southern Africa. MDA revealed that Khoe-San intra-sample variance is relatively high, with 44% of the sample (sexes pooled) classified into the Riet River group. The remaining individuals were classified (in decreasing order) into Bahutu (24%), Basuku (24%) and Sotho-Tswana (8%). Although the Khoe-San specimens are closest to the Riet River group, they are clearly not homogenous. Their high level of phenotypic diversity most likely originated from a complex population history involving many group interactions driven by social and political marginalization.

An assessment of the repeatability of pubic and ischial measurements.

Forensic anthropologists frequently use measurements of the human skeleton to determine sex and ancestry. Since the establishment of the Daubert criteria of admissibility of scientific evidence to court, methodologies used by anthropologists came under severe scrutiny. It is therefore important to ensure that the osteometric standards that are used in skeletal analyses are clearly explained, repeatable and reliable. Adams and Byrd (2002) found that measurements of the pelvis that originated from a point inside the acetabulum could not be repeated accurately. The purpose of this paper was to use three different sets of pubic and ischial measurements to establish whether they can be repeated with high precision between four different observers, and also by the observers themselves. Generally, high levels of repeatability were obtained, with intra-class correlations (ICC) above 0.8. Pubic and ischial measurements using a point in the acetabulum as origin performed the worst (ICC values of 0.82 and 0.79 respectively for inter-observer repeatability), whereas other methods performed better with ICC values above 0.9. It is advised that pubic and ischial measurements should be taken using the origin of the iliac blade as landmark.

A geometric morphometric study into the sexual dimorphism of the human scapula.

Sex determination is vital when attempting to establish identity from skeletal remains. Two approaches to sex determination exists: morphological and metrical. The aim of this paper was to use geometric morphometrics to study the shape of the scapula and its sexual dimorphism. The sample comprised 45 adult black male and 45 adult black female scapulae of known sex. The scapulae were photographed and 21 homologous landmarks were plotted to use for geometric morphometric analysis with the 'tps' series of programs, as well as the IMP package. Consensus thin-plate splines and vector plots for males and females were compared. The CVA and TwoGroup analyses indicated that significant differences exist between males and females. The lateral and medial borders of females are straighter while the supraspinous fossa is more convexly curved than that of males. More than 91% of the females and 95% of the males were correctly assigned. Hotelling's T(2)-test yielded a significant p-value of 0.00039. In addition, 100 equidistant landmarks representing the curve only were also assigned. These, however, yielded considerably poorer results. It is concluded that it is better to use homologous landmarks rather than curve data only, as it is most probable that the shape of the outline relative to the fixed homologous points on the scapula is sexually dimorphic.

Investigation into the usability of geometric morphometric analysis in assessment of sexual dimorphism.

Understanding sexual dimorphism is very important in studies of human evolution and skeletal biology. Sexual dimorphic characteristics can be studied morphologically and metrically, although morphologic studies pose several problems such as difficulties with quantification and interobserver error. Geometric morphometrics is a relatively new method that allows better assessment of morphologic characteristics. This paper aims to investigate the usability of this method by assessing three different morphologic characteristics in a sample of South African blacks: shape of the greater sciatic notch, mandibular ramus flexure, and shape of the orbits. Relative warps, thin-plate splines, and canonical variates analysis (CVA) analyses were performed. As expected, the shape of the greater sciatic notch provided the best separation between the sexes. Surprisingly, however, the shape of the orbits performed better that ramus flexure. Several possible explanations for this result are possible, which include the possibility that orbit shape is more sexually dimorphic than previously expected, or that biological reality is not reflected by this technique. More research is, however, needed.