ENAMEL THICKNESS AND THE TOPOGRAPHY OF THE ENAMEL-DENTIN JUNCTION IN SOUTH-AFRICAN PLIOPLEISTOCENE HOMINIDS WITH SPECIAL REFERENCE TO THE CARABELLI TRAIT

This study explores the internal morphology of early hominid teeth usi ng high-resolution computed tomography. Data on Carabelli feature size , enamel thickness, and the topography of the enamel-dentine junction are considered together in order to examine the relationship among the se variables in the maxillary molars of gracile and robust australopit hecines from South Africa. In particular, one aim is to investigate th e degree to which Carabelli feature size influences enamel thickness i n the plane of the mesial cusps. The results demonstrate that maxillar y molars attributed to Australopithecus africanus from Sterkfontein, T aung and Makapansgat possess larger Carabelli features and thinner ena mel along the lingual wall of the protocone than do specimens attribut ed to Paranthropus robustus from Swartkrans and Kromdraai. Distinct di fferences in the position of the Carabelli feature at the level of bot h the enamel-dentine junction and tooth crown surface between early ho minid species may help explain the observed disparity in enamel thickn ess at that region of the tooth crown as well as offer clues to the fu nctional role of Carabelli's cusp. As the size and position of the Car abelli feature affects the linear thickness of enamel at this one part icular region of the tooth crown, future comparative studies focusing on taxa that possess moderate to strong development of the Carabelli c omplex should use the linear thickness of enamel taken close to the pr otoconal dentine horn or at the maximum projection of the Carabelli's cusp. (C) 1998 Academic Press.