Reexamination of ancient jawbone found in Ethiopia concludes it came from Homo erectus infant

A global group of anthropologists, archaeologists, and geoscientists has discovered evidence that strongly implies the baby jawbone discovered in the Ethiopian highlands belonged to a Homo erectus youngster. The team used a variety of tests in their study, which was published in the journal Science, to determine the actual nature of the fossil.

A second team of researchers discovered the jawbone for the first time in 1981 at the Garba IV excavation site in the Ethiopian highlands; it was later dubbed Little Garba. Numerous organizations have examined the fossil throughout time to determine the individual's species. The genus Homo was determined to contain it, however there was no clear consensus.

The scientists working on this new project used synchrotron imaging on the teeth to identify the species and then compared the results with those of other hominin species. This indicated that Homo erectus was the closest match.

The jawbone is one of the oldest known Homo erectus fossils ever discovered. Previous studies had revealed that the sediment strata in which it was discovered were around 2 million years old, indicating that Little Garba lived around 2 million years ago.

Subsequently, the study team focused on the stone tools discovered at the same level at the excavation site. They discovered what they refer to as an advanced transition from Oldowan to Acheulean implements. Previous studies had shown that Little Garba's age, about 2 million years ago, corresponded with the development of such tools.

The data gathered at the Garba IV site leads the researchers to the conclusion that after Homo erectus populations arrived in the highlands, they had to adjust to the local climate and thinner air (Garba IV is located 2,000 meters above sea level). This entailed making improvements to their weapons and equipment so they could not only kill local animals but also prepare it for use as food and fuel in the colder highlands.