The 82nd Annual Meeting of the American Association of Physical Anthropologists (2013)


Metopism and early human brain evolution

RALPH L. HOLLOWAY1, DOUGLAS C. BROADFIELD2 and KRISTIAN CARLSON3,4.

1Department of Anthropology, Columbia University, 2Department of Anthropology, Florida Atlantic University, 3Institute for Human Evolution, University of Witwatersrand, South Africa, 4Department of Anthropology, Indiana University

Thursday 4:30-4:45, Ballroom C Add to calendar

A recent article by Falk et al (2012) has claimed that the presence of a metopic suture and an open anterior fontanelle on the Taung natural endocast indicates that the species Australopithecus africanus was undergoing prefrontal neural reorganization. They speculate that this reorganization is demonstrated by prefrontal outline widening, but do not show any convolutional changes that would mark such a neural reorganization. Instead, the authors speculate that these changes were probably necessitated by some adaptation to a “pelvic dilemma”. We show here that the Taung natural endocast does not show these metopic and fontanelle features, and that the prefrontal widening suggested for A. africanus is exceeded by bonobos and chimpanzees with smaller brain sizes. A careful examination of their Supplementary Data table claiming to have shown metopic sutures/anterior fontanelles in many early Homo endocasts indicates that most of the signs of metopic sutures are confined to the glabellar region of the frontal bone. Additional studies are being undertaken to settle the issue of metopism and fontanelles in the Taung specimen, and other early hominins.

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