The 81st Annual Meeting of the American Association of Physical Anthropologists (2012)

Dental microwear texture analysis of fossil bovids from Hadar, Ethiopia: implications for the paleoenvironment of Australopithecus afarensis


Doctoral Program in Environmental Dynamics, University of Arkansas

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Considerable paleoecological research has focused on the Pliocene locality of Hadar in Ethiopia, due to the long occupation by Australopithecus afarensis. In order to better understand the adaptations of these early hominins, it is necessary that reconstructions of the paleoenvironment are as accurate as possible. This study employs dental microwear texture analysis to reconstruct the diets of the local bovid fauna, frequently used as indicator taxa for habitat. To interpret the microwear signatures, the Hadar taxa are compared to a database including 25 extant bovid species with well understood diet and habitat preferences. This paper also addresses the paleoenvironments of the Sidi Hakoma, Denen Dora and Kada Hadar Members, as inferred from the dietary data. Clear differences in microwear textures were present among the members. The Sidi Hakoma bovids are reconstructed as browsers or browser-grazer intermediates, suggesting closed habitats and the presence of woodland resources. The Denen Dora bovids evince microwear textures ranging from obligate grazers to browser-grazer intermediates, indicating a mosaic habitat with access to both browse and graze. The Kada Hadar bovids primarily have variable or obligate grazing signatures, although a few browsing taxa are present. This suggests open habitats for grazing, although the presence of browsing taxa support a mosaic reconstruction for this member. The results presented here are consistent with a gradual aridification trend at Hadar. The microwear signatures of the fossil bovids indicate a transition from closed habitats comprising the Sidi Hakoma Member to a more open environment by the time of Kada Hadar deposition.

This research was funded by NSF Doctoral Dissertation Grant #0925822.

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