These fossil species between 8 million and 4.4 million years old include some of the earliest members of the hominin lineage.
These ancient human relatives include the first species with evidence of upright walking and running like humans. They represent more than a third of our evolutionary history.
The provocative idea that our genus arose with a deactivated muscle gene turned out to be wrong.
On a visit to Charles Darwin's home, I share some perspectives on how paleoanthropologists think about species.