1: The jawbone has been dated to 2.8 million years ago -- which predates the previously known fossils of the Homo lineage by approximately 400,000 years , according to Arizona State University . 2: The age of the fossil means it could help fill in an important gap in our knowledge . 3: It has been dated to 2.8 million years ago , which means it helps fill in a crucial gap in our knowledge .
1: 2.8 million years ago 2: The age of the fossil 3: 2.8 million years ago