An international team of geoscientists, archaeologists, and anthropologists have unveiled compelling evidence indicating that an infant jawbone discovered in the Ethiopian highlands originates from a Homo erectus child. Their findings, published in the journal Science, stem from an extensive study encompassing numerous tests aimed at unraveling the true identity of the fossil.
The initial unearthing of the jawbone took place in 1981 at the Garba IV excavation site in the Ethiopian highlands by a separate team of researchers, affectionately naming it “Little Garba.” Throughout the years, multiple research groups have analyzed the fossil to determine the species of the individual, with no unanimous agreement. However, it was established that the specimen belonged to the Homo genus.
To definitively categorize the species, the scientists on this recent endeavor utilized synchrotron imaging to closely examine the teeth, ultimately comparing these images to those of other hominin species. This analysis pointed to Homo erectus as the closest match.
Previous research had established that the sediment layers in which the jawbone was nestled were approximately 2 million years old, implying that Little Garba lived around 2 million years ago, making this jawbone one of the most ancient Homo erectus fossils ever discovered.
Subsequently, the research team directed their attention to the stone tools found at the same stratum in the excavation site. They observed what they describe as a shift from Oldowan tools to more advanced Acheulean tools. Earlier research had indicated that such tools emerged approximately 2 million years ago, aligning with the age of Little Garba.
The researchers surmise that the evidence unearthed at the Garba IV site suggests that once Homo erectus populations arrived in the highlands, they had to adapt to the higher altitude (Garba IV is situated at 2,000 meters above sea level) and the challenging geographical conditions. This adaptation involved enhancing their tools and weaponry, enabling them not only to hunt local prey but also to process it for sustenance and materials to combat the cooler highland climate.