PMID: 6403498Jan 1, 1983Paper

Analysis of the dental morphology of Plio-pleistocene hominids. I. Mandibular molars: crown area measurements and morphological traits

Journal of Anatomy
B A Wood, S A Abbott

Abstract

This study has used accurate measurements of crown area and precise assessments of the morphological traits of mandibular molars in an attempt to define the metrical and morphological characteristics of early hominid taxa. A total of 196 Plio-Pleistocene hominid molars were either allocated to one of six informal taxonomic groups or considered as individual cases. Accurate measurements of crown base area made from occlusal photographs have enabled us to estimate the effects of interproximal wear on crown areas. The average correction factor over the three molar types is around 2-4% with a maximum of 6%. The patterns of distribution of extra cusps show interesting differences between taxa. None of the M-1S in the two groups of 'gracile' hominids from East and South Africa bears a C6, but it is common in the two 'robust' taxa. The distribution of a C7 is the reverse of this, it being rare in the robust' taxa, and more common in the 'gracile' groups. There is thus no simple relationship between cusp number and tooth size. Our observations on the protostylid suggest that though it is more common in the 'robust' australopithecines than the 'graciles', when it does occur it is more strongly expressed in the 'gracile' group. The combi...Continue Reading

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