The feeding biomechanics and dietary ecology of Australopithecus africanus

Published

February 19, 2009

Author(s)

Brian R. Lawn, David Strait, Gerhard Weber, Simon Neubauer, Janine Chalk, Brian Richmond, Peter Lucas, Mark Spencer, Caitlin Schrein, Paul Dechow, Callum Ross, Ian Grosse, Barth Wright, Paul Constantino, Bernard Wood, Qian Wang, Dennis Slice, Craig Byron, Amanda Smith

Abstract

The African Plio-Pleistocene hominins known as australopiths evolved a distinctive craniofacial morphology that traditionally has been interpreted as a dietary adaptation1 for feeding on small, hard objects2. This adaptive complex includes large postcanine tooth crowns covered with thick enamel, mandibles with large, robust bodies, exaggerated markings for the masticatory muscles, and substantial bony buttressing of the face. A classic analysis of this morphology hypothesizes that loads applied to the premolars during feeding had a profound influence on the evolution of australopith craniofacial form3. Here, we test this hypothesis using finite element analysis (FEA) in conjunction with comparative, imaging, and experimental methods. We find that the facial skeleton of one of these early hominins, Australopithecus africanus, is well suited to withstand premolar loads. However, we suggest that the mastication of small objects is unlikely to fully explain the evolution of facial form in this species. Rather, craniofacial morphology in australopiths is more likely to be related to the ingestion and initial preparation of larger, mechanically protected food objects like large nuts and seeds. These foods may have been critical resources that australopiths relied on during periods when their preferred dietary items were in short supply 4-7. Our analysis reconciles apparent discrepancies between dietary reconstructions based on biomechanics, tooth morphology and dental microwear2-4,6,8,9.

Citation

Nature

Pub Type

Journals

Keywords

fracture, teeth, hominids, food objects

Citation

Lawn, B. , Strait, D. , Weber, G. , Neubauer, S. , Chalk, J. , Richmond, B. , Lucas, P. , Spencer, M. , Schrein, C. , Dechow, P. , Ross, C. , Grosse, I. , Wright, B. , Constantino, P. , Wood, B. , Wang, Q. , Slice, D. , Byron, C. and Smith, A. (2009), The feeding biomechanics and dietary ecology of Australopithecus africanus, Nature (Accessed April 19, 2024)