‘Do larger molars and robust jaws in early hominins represent dietary adaptation?’ A New Study in Tooth Wear

Anna Clement,Simon Hillson

doi:10.5334/ai.1605

Abstract

Diet imposes significant constraints on the biology and behaviour of animals. The fossil record suggests that key changes in diet have taken place throughout the course of human evolution. Defining these changes enables us to understand the behaviour of our extinct fossil ancestors. Several lines of evidence are available for studying the diet of early hominins, including craniodental morphology, palaeoecology, dental microwear and stable isotopes. They do, however, often provide conflicting results. Using dental macrowear analysis, this new UCL Institute of Archaeology project will provide an alternative source of information on early hominin diet. Dental macrowear has often been used to analyse diet in archaeological populations, but this will be the first time that this type of detailed study has been applied to the early hominin fossil record.

Highlights

Diet imposes significant constraints on the biology and behaviour of animals
Four different taxa within these two main genera are well known within the fossil record – Australopithecus afarensis and Paranthropus boisei from sites in East Africa and Paranthropus robustus and Australopithecus africanus from sites in South Africa (Fig. 1)
To remove age as a factor, we present the dentine proportion of each tooth as a ratio of the dentine proportion of another tooth from the same jaw

Summary

Introduction

Diet imposes significant constraints on the biology and behaviour of animals. The fossil record suggests that key changes in diet have taken place throughout the course of human evolution. Craniodental evidence Compared with most primates, both living and extinct, Australopithecus and Paranthropus had relatively large, flat, thick enamelled cheek teeth held within robust jaws with large muscle attachments (Robinson, 1956; Wolpoff, 1973; Rak, 1983; Wood and Abbot, 1983; Kay, 1985; Martin, 1985; Benyon and Wood, 1986; Macho and Thackery, 1992; Teaford and Ungar, 2000; Ungar, 2004; Lucas, 2007) These features have been interpreted as adaptations for masticating a mechanically resistant diet that demanded the generation of a powerful bite force over a broad grinding area of teeth (Kay, 1981; Walker, 1981; Demes and Creel, 1988; Hylander, 1988; Daegling and Grine, 1991; Teaford and Ungar, 2000; Strait et al, 2009). This is interpreted as the result of less emphasis being placed on foods that required substantial incisor use, such as those with large thick husks and hard seeds surrounded by a thick layer of flesh (Teaford and Ungar, 2000)

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Methods

Conclusion