‘H. Naledi an animal on the cusp of transition’

The spotlight in human evolution had long since shifted to the Great Rift Valley of East Africa.

Lee Berger, the American paleoanthropologist got a job at the University of the Witwatersrand, Wits, to hunt for fossils in the 1990s, but Berger has almost alone in arguing that South Africa was the place to look for the true earliest Homo.

Berger’s finds and theories in 2008 were dismissed by most scientists.

It was announced on Thursday in the journal eLife that a new species of human ancestor was found deep in a South African cave, perhaps adding a baffling new branch to the family tree.

Homo naledi, as they call it, appears very primitive in some respects—it had a tiny brain, for instance, and apelike shoulders for climbing.

“The message we’re getting is of an animal right on the cusp of the transition from Australopithecus to Homo,” Berger said. “Everything that is touching the world in a critical way is like us. The other parts retain bits of their primitive past.”

The fossil record is frustratingly ambiguous. Slightly older than H. erectus is a species called Homo habilis, or “handy man”—so named by Louis Leakey and his colleagues in 1964 because they believed it responsible for the stone tools they were finding at Olduvai Gorge in Tanzania.

In the 1970s teams led by Louis’s son Richard found more H. habilis specimens in Kenya, and ever since, the species has provided a shaky base for the human family tree, keeping it rooted in East Africa.

Before H. habilis the human story goes dark, with just a few fossil fragments of Homo too sketchy to warrant a species name.

As one scientist put it, they would easily fit in a shoe box, and you’d still have room for the shoes.

A South African chartered accountant who was exploring the Rising Star cave for fun stumbled onto the bones by chance.

They took photographs, and then decided to head to Professor Berger’s house to show him the pictures.

Because funding came from National Geographic (Berger is also a National Geographic explorer-in-residence), they now claim the find.

Berger gathered some 60 scientists and set up an aboveground command center, a science tent, and a small village of sleeping and support tents.

Marina Elliott, then a graduate student at Simon Fraser University in British Columbia, was the first scientist down the chute.