Human fossils from Omo Kibish

Article By:

Royer, Danielle Department of Anthropology, Stony Brook University, Stony Brook, New York

Last reviewed:2010

DOI:https://doi.org/10.1036/1097-8542.YB100025

In 1967, paleontologists made a series of major fossil discoveries of early humans in the ancient sedimentary layers of the Kibish Formation along the banks of the Omo River in southwestern Ethiopia (Fig. 1). Omo I, the most complete specimen discovered, consists of numerous fragments of the skull, teeth, and much of the skeleton, including several limb bones, whereas Omo II preserves only a nearly complete neurocranium, the portion of the skull that surrounds the brain. While the modern appearance of Omo I was quickly accepted by most paleoanthropologists (that is, specialists in the study of human evolution), the Omo II skull was described as more primitive, with many similarities to more ancient members of the human lineage. In the years following these discoveries, the importance of the Kibish fossils for understanding the origins of our own species, Homo sapiens, was surrounded by considerable speculation and confusion about the age and exact provenance of these fossils. Motivated by this, researchers recently returned to the Kibish Formation to clarify the many ambiguities surrounding the fossils found decades earlier, as well as to search for new fossil and archeological material. Their efforts yielded new fossils and a wealth of stone tools, and also provided an age of approximately 195 KYA (thousand years ago) for the fossils, securing their place as the earliest evidence of our own species yet recovered. Thus, in the decades since their initial discovery, the human fossils from the Omo Kibish continue to occupy a critical role in our understanding of modern human origins and provide insight into the last 200,000 years of human evolution.

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