A team of researchers from UC Berkeley and the Los Alamos branch of the Institute of Geophysics and Planetary Physics (IGPP) announced in July the discovery of fossil bones and teeth belonging to the earliest human ancestors yet discovered—a chimpanzee-sized hominid who walked the wooded highlands in what is now a desert region of Ethiopia between 5.2 and 5.8 million years ago.
The team was led by Berkeley Professors Desmond Clark and Tim White, Berkeley graduate student Yohannes Haile-Selassie and IGPP Los Alamos geologist Giday WoldeGabriel, with technical and financial support from IGPP Los Alamos and funding from the National Science Foundation. They found fossil bones that predate the oldest previously discovered human ancestor by more than a million years. The hominid is part of a newly named subspecies of early man called Ardipithecus.
The discovery is an outcome of the Middle Awash Paleoanthropological and Geological Project headquartered at IGPP Los Alamos—an international, multidisciplinary effort whose objective is the elucidation of human origins and evolution. IGPP scientists associated with the project have, under the leadership of Dr. WoldeGabriel, supported the paleoanthropological research through study of the volcanic and tectonic evolution of the Middle Awash area in Ethiopia, recovering evidence for early hominid origins and evolution, and placing this evidence in controlled spatial, temporal, and environmental contexts. They have assessed the geological forces responsible for rifting, volcanism and other geomorphic processes that have resulted in accumulations of more than 500 meters of sediment and volcanic rock on the rift floor over the past 15 million years.
All geological samples collected during the field investigations were brought to Los Alamos for analysis. WoldeGabriel and current IGPP Director Dr. Grant Heiken used electron microscopes and microprobes to study the samples, collaborating with other laboratories in establishing dates for the geological samples—which, in turn, confirmed the antiquity of the hominid find. Over the past ten years five other hominid species from the region have been discovered and dated in this manner, making the Middle Awash Project the most successful effort of its kind in the world.
Encouraged by Dr. Chick Keller, former director of IGPP Los Alamos, this international and multidisciplinary project has fostered first class research collaborations among sister institutions and scientists from both LANL, Berkeley and other universities and research laboratories in Ethiopia, the U.S. and Europe.
Dr. WoldeGabriel and other IGPP colleagues characterize the newly discovered hominid’s environments as 1,500 feet higher in elevation than today, much cooler and wetter, and subject to regular showers of thick volcanic ash.
“It’s hard to imagine that life would go on under such hostile conditions,” WoldeGabriel said. “Ardipithecus and the other animals inhabiting the region were real survivors.”