ADDIS ABEBA – A skull of “a remarkably complete” human ancestor lived 3.8 million years ago has been found in eastern Ethiopia.
The cranium fossil, referred as MRD, was found buried along a river delta on the edge of a lake at the Woranso-Mille paleontological site in Afar regional state three years ago, following 15-year-long research.
This is the first time a skull belonging to Australopithecus anamensis has been found and the discovery sheds light on the evolutionary history of early human ancestors.
Researchers found the upper jaw on February 16, 2016. They searched the area for more pieces over 16 hours and recovered the rest of the skull.
“I couldn’t believe my eyes when I spotted the rest of the cranium,” said Yohannes Haile-Selassie, a study author and curator of physical anthropology at the Cleveland Museum of Natural History in the U.S. “It was a eureka moment and a dream come true. This is one of the most significant specimens we’ve found so far from the site.”
The skull represents the early human ancestor known as Australopithecus anamensis that lived between 3.9 and 4.2 million years ago.
They are the ancestor of Australopithecus afarensis, to which the famed Lucy skeleton belonged, and is believed to have given rise to our genus, Homo. Afarensis came along later, living between 3 and 3.8 million years ago.
The MRD was found only 34 miles north of where the Lucy skeleton was recovered in 1974. An international team of geologists, paleobotanists and paleoanthropologists helped to determine the age of the skull by studying the habitat where it was found.
The anamensis skull, which likely belonged to a male, was transported a short distance down a river after death and buried by sediment in a delta, said Beverly Saylor, the study author.
It was likely living along the river, which was surrounded by trees. The larger area away from the river was open shrubland.
Previously, researchers believed that anamensis, which was only previously known from isolated bone fragments, died off and gave rise to afarensis. But the skull discovery reveals that the two species likely overlapped and co-existed for at least 100,000 years.
This challenges the idea that human ancestors evolved in a linear fashion.
The findings are published in the journal Nature.
Photo Caption: A facial reconstruction and skull belonging to an early human ancestor that lived 3.8 million years ago discovered in Ethiopia. (Credit: Cleveland Museum of Nat. History via CNN)