Can you bite a nut?

An international research team found that a more than two million year-old early human ingested large nuts and seeds that may have been "foods of last resort". The ability to eat foods that were difficult to process could have been an ecologically significant adaptation. The article "The feeding biomechanics and dietary ecology of Australopithecus africanus," is the first of a series devoted to the study of the mechanics of feeding in primates and Australopithecines.

The results showed that Australopithecus africanus, a human relative that lived in South Africa over two million years ago, had a facial skeleton that was well designed to withstand premolar bites. This suggests that A. africanus might have used its enlarged premolars and structurally reinforced face to crack open and ingest large hard nuts. These nuts may have been critical resources upon which these humans relied during times of resource scarcity or when their preferred foods were unavailable.

Advanced Techniques
The scientists implement advanced techniques for their research. The team of Gerhard Weber from the University of Vienna provided the basis with Virtual Anthropology (VA). Then David Strait and his workgroup from the University of Albany, NY, conducted the Finite Element Analysis (FEA). The FEA an engineering method used to examine how objects of complex geometry respond to loads.

University of Vienna: Center of Virtual Anthropology
Before FEA can be applied, an accurate 3D model of the fossil’s skull is needed. At University of Vienna, Gerhard Weber’s workgroup “Virtual Anthropology” is one of the few centers where such kind of reconstructions of fossil specimens can be undertaken. After scanning the fossils with computer tomography the digital copies can be handled and measured electronically. Also unwanted structures like former plaster reconstructions or embedded stone matrix can be removed without touching the precious originals again. “In this case we were lucky to have teeth available from a very similar other specimen so that we could reconstruct the edentulous face of ‘Mrs. Ples’, as the fossil is called” says Weber.

Gerhard Weber leads a European network funded by the EU (European Virtual Anthropology Network – EVAN). The network aims to spread this kind of technology in Europe and to train young researchers. Applications meanwhile reached the medical sector as well where diagnosis and implant planning exploit the same methods as those used for investigating fossils.

The international project is funded by the National Science Foundation and the European Union. It enables collaboration between US American universities and EVAN.

Figure legend:

Left: The original skull of Mrs. Ples (Sts 5) from South Africa (~ 2.5 Million years old). Note the plaster reconstruction of the original skull (white) and the stone matrix in the eye sockets. (courtesy of Transvaal Museum, Pretoria)

Middle: The reconstructed skull with teeth fitted from another specimen (Sts 52), plaster and stone matrix removed and bone reconstructed, and the cavities like the braincase (red) and the paranasal sinuses (blue) segmented. This is the basis for the biomechanical modelling following in the next step. (By Simon Neubauer & Gerhard Weber)

Right: The loading FEA-experiment shows the stress in the skull of Australopithecus africanus imposed by biting on the premolar teeth. Bright colors correspond to high stresses, and indicate that a bony pillar running alongside the opening of the nasal cavity acts as a strut that structurally reinforces the face such loads. (By David Strait).

Contact person in Europe:
Gerhard W. Weber
Department of Anthropology
University of Vienna
Althanstr. 14, A-1090 Vienna, Austria
M +43-664-817 49 26
gerhard.weber(at)univie.ac.at
www.evan.at
www.virtual-anthropology.com