The 85th Annual Meeting of the American Association of Physical Anthropologists (2016)


Enamel-dentine junction morphology and enamel thickness of the Dinaledi dental collection

MATTHEW M. SKINNER1,2,3, ANNABELLE L. LOCKEY1, PHILIPP GUNZ3, JOHN HAWKS2,4 and LUCAS K. DELEZENE2,5.

1School of Anthropology and Conservation, University of Kent, 2Evolutionary Studies Institute, University of Witwatersrand, 3Department of Human Evolution, Max Planck Institute for Evolutionary Anthropology, 4Department of Anthropology, University of Wisconsin-Madison, 5Department of Anthropology, University of Arkansas

April 16, 2016 8:45, Imperial Ballroom A Add to calendar

The dental remains of the H. naledi hypodigm constitute one of the largest samples of teeth and jaws of any fossil hominin species. Estimated to derive from at least 15 individuals, they offer an opportunity to characterize dental morphology in a temporally and geographically restricted population belonging to the genus Homo. We apply microtomography to examine the morphology of the enamel-dentine junction (EDJ) of the mandibular molar sample. Previous research has demonstrated that EDJ morphology carries a strong taxonomic signal, facilitates the examination of discrete dental traits, and provides insights into the developmental processes underlying tooth crown morphology. Using geometric morphometrics (GM), we compare molar EDJ morphology of the H. naledi remains to a comparative sample that includes numerous Plio-Pleistocene hominin species from Australopithecus, Paranthropus and Homo. We also measure 2D average and relative enamel thickness and conduct a qualitative analysis of the EDJ expression of dental traits. Results of the GM analysis indicate that the molars of H. naledi are distinct from both Australopithecus/Paranthropus and early/later Homo; presenting a unique combination of dentine horn size and spacing and cervix shape. 2D enamel thickness of H. naledi is relatively thick, overlapping with P. robustus and some specimens of early Homo. Discrete traits, such as cusp 6 and the protostylid, are both rare and only mildly expressed and the molar occlusal basin lacks complexity in terms of crest development. The molar EDJ morphology of H. naledi is discussed within the context of both early and later species of the genus Homo.

This research was supported by the Max Planck Society, the National Geographic Society and the National Research Foundation of South Africa.