HUMAN EVOLUTION

The First of Our Genus

~2.8 million years ago

Phanerozoic · Cenozoic · Neogene · Pliocene

Half a lower jaw, picked up on an Ethiopian hillside, carries teeth arranged as ours are and a chin line still shaped like an Australopithecus. At 2.8 million years it is the oldest fossil anyone assigns to Homo, and the first Oldowan tools follow it by about two hundred thousand years. Newer finds from the same area show Homo again at 2.6 million years and an Australopithecus alongside it at 2.63, belonging to no known species.

Why it matters

The picture that emerges is not a relay race. For at least three hundred thousand years our genus shared the Afar with another upright lineage that was not on its way to becoming us. The origin of Homo is a branch inside a crowd, and the crowd is the part we keep forgetting.

Dating & uncertaintyDisputed

The jaw, catalogued LD 350-1, was published in 2015 and challenged in the same journal within months: the traits used to call it Homo are few, and the specimen is broken. Nothing since has settled the question, and a single jaw is a thin foundation for the origin of a genus.

Sources

1. Villmoare et al. (2015), Science · Early Homo at 2.8 Ma from Ledi-Geraru, Afar, Ethiopia
2. Villmoare et al. (2026), Nature · New discoveries of Australopithecus and Homo from Ledi-Geraru, Ethiopia
3. Braun et al. (2019), PNAS · Earliest known Oldowan artifacts at >2.58 Ma from Ledi-Geraru, Ethiopia, highlight early technological diversity
4. Hawks et al. (2015), Science · Comment on “Early Homo at 2.8 Ma from Ledi-Geraru, Afar, Ethiopia”

Earth history as one day

23:59:0653.3 s before midnight

if Earth’s 4.54 billion years were compressed into a single day