The 2.8m-year-old human lineage jaw bone fossil was found in the Afar region Ethiopia by fossil hunters…are the oldest remains ever found that belong to the genus Homo, the lineage that ultimately led to modern humans…about 250 miles from Addis Ababa…when the now parched landscape was open grassland and shrubs nourished by tree-lined rivers and wetlands.
The discovery sheds light on a profoundly important but poorly understood period in human evolution that played out between two and three million years ago, when humans began the crucial transformation from ape-like animals into forms that used tools and eventually began to resemble modern humans.
“This is the the first inkling we have of that transition to modern behaviour. We were no longer solving problems with our bodies but with our brains,”
The picture that emerges from the fossil record is that 3m years ago, the ape-like Australopithecus afarensis died out and was superseded by two very different human forms. One, called Paranthropus, had a small brain, large teeth and strong jaw muscles for chewing its food. The other was the Homo lineage, which found itself with much larger brains, a solution that turned out to be more successful.
“By finding this jaw bone we’ve figured out where that trajectory started…This is the first Homo. It marks in all likelihood a major adaptive transition.”…the region was much wetter than Hadar where Lucy was found. Remnants of antelopes, prehistoric elephants, primitive hippos, crocodiles and fish were all recovered from the Ledi-Geraru site, researchers said. Details of the discoveries are reported in two papers published in Science.