Laetoli revisited: Renewed paleontological and geological investigations at localities on the eyasi plateau in northern Tanzania

Laetoli, one of the key paleontological and paleoanthropological localities in Africa, is renowned for the recovery of fossil remains of early hominins belonging to Australopithecus afarensis and for the remarkable trails of hominin footprints. In addition, the faunas from the Upper Laetolil Beds (3.63–3.85 Ma) and Upper Ndolanya Beds (2.66 Ma) are from time periods that are generally poorly represented at other paleontological sites in East Africa. Fossils from these stratigraphic units provide important insights into the faunal and floral diversity during the Pliocene, and they serve as reliably dated reference faunas for comparison with other Plio-Pleistocene sites in Africa. The paleoecology of Laetoli is unusual for early hominin sites in East Africa in the absence of evidence for extensive or permanent bodies of water, and in having habitats that are reconstructed as being less densely wooded. Therefore, Laetoli provides key evidence for interpreting the possible diversity of hominin habitat preferences and for understanding ecological changes in East Africa during the Pliocene. The main goal of renewed fieldwork at Laetoli, starting in 1998, was to recover additional fossil hominid specimens and to obtain more detailed contextual information on the paleontology, geology, dating, and paleoecology. The substantially expanded fossil collections have added significantly to our understanding of the systematics and paleobiology of Pliocene East African faunas. The recovery of new Australopithecus afarensis specimens from the Upper Laetolil Beds has contributed information on the morphology, variation and evolutionary status of this taxon. Fossil hominins have been recovered for the first time from the Upper Ndolanya Beds. These include the first specimen of Paranthropus aethiopicus to be recovered from outside the Turkana Basin, and one of the oldest securely dated specimens definitively attributable to this taxon.