Abstract:
The study of the human metatarsals reveals frequent morphological variations from the typical descriptions. Pathologies of these bones in contemporary humans are common, and it has been suggested that some of these may be associated with some of these variants. Within this context, it was not clear to what extent footwear and other environmental factors such as modern substrates have influenced metatarsal
morphology.
This study essentially consists of three parts. First a preliminary morphometric study of the first, second and fifth metatarsals, to demonstrate the broad patterns of discrimination between selected hominoidea, namely humans, gorillas, chimpanzees and orangutans. In addition, the SKX 5017 first metatarsal fossil thought to be of Paranthropus robustus was included. Second, a primary morphometric investigation into the patterns of morphological discrimination in the five metatarsals of selected humans from South Africa, namely Sotho, Zulu, European and pre-pastoral subgroups. The contemporary human subgroups are associated with modern lifestyles and the pre-pastoral individuals represent habitually unshod forager societies from the western and southern Cape, dated 9750 - 2000 B.P. Third, a non-metric investigation into the patterns of variation in epigenetic and pathological variants of the metatarsus of the four human subgroups.
A suite of existing metrical data was utilized for the preliminary hominoid study, and a suite of metrical and non-metrical data was collected for the primary human study from appropriate skeletal collections. Univariate analysis of these iv samples revealed important, though simplistic trends in morphology. Subsequent
multivariate analyses utilizing principal components and canonical variates analysis
were undertaken.
Multivariate analysis of the hominoid samples revealed large scale variation between the species. This discrimination was on the basis of genetics, locomotor function and geography. Multivariate analysis of the human metrical data revealed very subtle morphological discrimination within and between the subgroups. Most of this discrimination appears to be genetic, followed by a functional or life-style based discrimination suggesting a broad discrimination between recent humans and the
habitually unshod pre-pastoral subgroup.
The epigenetic traits reveal considerable variation within groups, with similar trends between them. All subgroups have an appreciable number of identifiable pathological changes, with the recent human subgroups having the most and the prepastoral subgroup the least. In all subgroups, the hallucal metatarsal displays by far the greatest frequency in osseous modification.
The main conclusions of this study are:
1.) The general patterns of morphological discrimination between the metatarsals of the human subgroups are very subtle. The non-metric traits are very variable, but do not discriminate between any of the subgroups.
2.) Both recent and ancient human groups present with similar patterns of pathological changes, but the frequency is different, these changes are to a great extent influenced by lifestyle. Regardless of temporal context, no clear correlation between morphological variation and pathological changes could be found.
