The recognition, frequency, and taxonomic association of skeletal pathology from selected Plio-Pleistocene-aged sites from the Cradle of Humankind, Witwatersrand, South Africa

• Main Author: Franklin, Ryan D.
• Format: Others
• Language: en
• Published: 2011
• Online Access: http://hdl.handle.net/10539/9238

Skeletal pathology has been largely unexplored from South African Plio-Pleistocene cave contexts. As a result, there is little known about the types of pathology present in these assemblages or the frequencies at which they occur. This study was designed to identify and analyze skeletal pathology from two sites in the Cradle of Humankind, South Africa. Over 7000 postcranial fossils, representing the broad range of macromammalian taxa from the early hominid sites of Cooper‟s D and Swartkrans (Members 1-3), were examined for evidence of gross skeletal pathology. Frequencies of pathology were recorded at order and family levels and the elements were categorized to skeletal section to identify possible trends in the anatomical location of lesions. Chi-square and randomization tests for goodness-of-fit were conducted at family level and by skeletal section to note any significant disagreement between observed and expected frequencies of pathology. Pathological fossils were described and lesions were identified to broad diagnostic categories. In total, twenty-four pathological fossils were identified from Cooper‟s D and forty from Swartkrans. Joint disease, trauma and enthesopathy are the most common disease types from both sites. For the Swartkrans fauna there is the additional presence of neoplasia. The frequency of pathology at order level is similar for both sites, with artiodactyls showing the lowest frequency, followed by carnivores and primates. Pathology by family occurs at frequencies of between 0 and 6%. Hominids fall outside of this range, occurring at a frequency of 100% for Cooper‟s D and 16% for Swartkrans. For both sites there is a significant disagreement between the observed and expected frequencies of pathology for bovids, felids and hominids. This indicates that pathology does not occur in equal proportion throughout the assemblage, but rather occurs at high frequency for felids and hominids and low frequency for bovids, possibly correlated to the trophic roles of the different taxa. It was, however, found that pathology predominantly occurred on the same elements for all families, specifically the vertebrae and distal-limb. Chi-square and randomization tests by skeletal section revealed a non-significant result for Cooper‟s D (P = 0.07) and a significant result for Swartkrans (P = 0.03). For Swartkrans there is a significant disagreement between the observed and expected frequencies of pathology for distal-limb and hindlimb elements. This result may be due to the high frequency of pathology on hominid distal elements, explained, in part, by a mechanical stress aetiology involving activity related to hominid grip and grasping.