Morphological affinities of the proximal ulna from Klasies River main site: Archaic or modern?

The Middle Stone Age (MSA) asociated hominids from Klasies River Mouth (KRM) have taken on a key role in debate about the origins of modern humans, with their craniofacial remains seen as either representing the earliest well-dated modern humans in southern Africa or orthognathic late archaic humans. Diagnostic postcranial remains from Klasies are few, but one specimen - a proximal right ulna from the lower SAS member - is useful for assessing the morphological affinities of these hominids. Canonical variates analysis using 14 proximal ulnar dimensions and comparative data from European, west Asian and African archaic humans, and Levantine Mousterian, European Upper Paleolithic, African Epipaleolithic and diverse recent modern human samples (many of recent African descent) were employed to assess the morphological affinities of this specimen. Results suggest an archaic total morphological pattern for the Klasies ulna. Analysis of diaphyseal cross-sectional geometry reveals an ulnar shaft with relatively thick cortical bone, but the specimen cannot be readily distinguished from Neandertals or early anatomically modern humans on the basis of shaft cross-sectional properties. If the isolated ulna from Klasies is indicative of the general postcranial morphology of these hominids, then the MSA-associated humans from KRM may not be as modern as has been claimed from the craniofacial material. It is possible also that the skeletal material from KRM reflects mosaic evolution - retention of archaic postcranial characteristics, perhaps indicating retention of archaic habitual behavior patterns, in hominids that were becoming craniofacially modern. © 1996 Academic Press Limited.

Duke Scholars

Author Steven E. Churchill Evolutionary Anthropology