The earliest elephants out of Africa: Taxonomy and taphonomy of proboscidean remains from Bethlehem

摘要

The bone-bearing beds of Bethlehem were excavated by Gardner and Bate in the late 1930s, yielding an important Plio-Pleistocene faunal assemblage. In the 1950s, Hooijer revised the fauna and described elephant remains, including a large tusk, a mandible, several molars and some post-cranial elements, identified by him as Archidiskodon cf. planifrons. Recent preparation and Computed Tomography has given new insights into the early elephant remains from Bethlehem - both in terms of their anatomy and their post-depositional deformation. This includes two further mandibles, distorted and almost totally obscured by sediment, whose morphology has been revealed. The elephant material has been studied in detail and compared morphometrically with key taxa including Siwalik Elephas planifrons and European Mammuthus rumanus. The morphology of the molars cannot definitively distinguish between Elephas or Mammuthus, but their evolutionary grade, and the morphology of the mandible, are most conformable with a primitive mammoth intermediate between African M. subplanifrons and European M. rumanus. Conversely a largely complete tusk shows none of the spiral twisting associated with Mammuthus and is more conformable with Elephas. The possibility that two elephantid taxa are represented in the Bethlehem deposit cannot be discounted, and is consistent with a wide size variation seen among the postcranial bones. These remains, together with some others recently described, represent the most primitive known elephantines out of Africa. (C) 2016 Elsevier Ltd and INQUA. All rights reserved.