Professor Lee Berger led the expedition that unearthed a discovery, which now looks set to raise deep questions about what it means to be human.
“We never imagined finding anything like this.”
Berger, a paleo-anthropologist, says he feels privileged to be at the centre of this historic discovery.
“I feel very privileged, I think my colleagues feel very privileged. We also feel very privileged at the attention that the public and media has given to this scientific story because human origins isn’t just a scientific story, it’s our science story.”
Berger, says the discovery was made in September 2013 and has been kept secret until now.
Scientists this morning have revealed the discovery of a new species of human relative, that they believe disposed of its dead deep in a cave and possibly even used fire.
Homo naledi is the latest addition to the human evolutionary tree and was discovered in the Cradle of Humankind, about 40 kilometres west of Johannesburg. Naledi means star in Sesotho. This latest find, believe scientists, is going to shake up that tree, as this species could have displayed behaviour that so far has only been seen in humans and Neanderthals
He says the years spent researching the finding have been worth it.
Professor Lee Berger of Wits University, who led the team that made the discovery, revealed
“What we have is a tall hominid, between 1,45 and 1,5 metres tall, was very skinny, had powerful joint muscles and had a brain about the size of my fist,” explained Berger in a pre-announcement briefing.
The scientists have so far excavated and analysed 1550 fossils retrieved from the chamber, which make up 15 individuals.
This makes it the single largest haul of fossils yet made on the continent of Africa. And scientists say there are more down there.
Discoveries like this in the past have fundamentally changed our understanding of human ancestry.
“What we’re announcing today is the product of one of the largest scientific endeavours ever to occur in the history of palaeontology, bringing scientists from all over the world to study not only the fossils themselves but also the context of the fossils.”
The mystery is how this hominid, ended up in the chamber, which has been named the Dinaledi Chamber, or “Chamber of Stars”.
The researchers have proposed that Homo naledi moved into the cave on purpose to dispose of their dead.
Berger said they had eliminated the possibility that the bones had arrived in the cave because of carnivore activity. He also said that the bones had not been moved by water or died in a singular event.
To get to the chamber, Homo naledi, explained Berger, would have had to have dragged their dead through pitch black tunnels. It is possible, he said, that they might have used fire to light their way.
Their findings have been described in two papers that have been published in the scientific journal eLife.
The initial discovery was made in September 2013 when two cavers exploring the Rising Star Cave system, came across a mandible. Two months later Wits University with National Geographic launched a three week long expedition to recover what initially was thought to be a single specimen. Volunteers small enough to climb down the narrow chute were recruited and used to do the excavation.
“We didn’t know what we had. By day three, we realised it was not a skeleton, we had more than that, it was multiple skeletons,” Berger said. In the chamber, they found infants, adults and even the aged.
Homo naledi is unique in that it has a mix of primate and human-like features. The shoulders are similar to apes while the feet are distinctly human-like.
“Surprisingly, Homo naledi has extremely curved fingers, more curved than almost any other species of early hominin, which clearly demonstrates climbing capabilities. This contrasts with the feet of H. naledi, which are “virtually indistinguishable from those of modern humans,” said Dr William Harcourt-Smith of Lehman College, City University of New York, and the American Museum of Natural History, who led the study of Homo naledi’s feet.
He believes the feet with the long legs might have also made Homo naledi suitable for long-distance walking.
But as yet scientists don’t know where Homo naledi sits on man’s evolutionary tree as they have been unable to date the species as yet.
This is something, Berger said, that it being worked on.
Deputy President Cyril Ramaphosa is going to receive a private viewing, and then will address the nation about the significance of the discovery.
Wits University has described the find as a groundbreaking discovery of international importance.
Gathering the fossils was dangerous work.
Berger, a National Geographic Explorer-in-Residence, was already well-known for his discovery of “Australopithecus sediba,” another species of human ancestor, in 2008. But this expedition would face unique challenges.
The fossils were found at the end of a series of chambers and tight squeezes deep underground, some 90 meters (100 yards) from the cave entrance. To get there, scientists would have to squeeze through a 7-inch wide cave opening.
So Berger put out a call on social media for skinny scientists and cavers who could fit through the tiny chute and bring up the bones.
Within days Berger had dozens of responses, and he eventually selected a team of six “underground astronauts” — all women — to do the job.
Berger himself could not reach the chamber where the remains lay, but he followed all of the exploration on real-time monitors above ground and communicated with his team.
“It is the heart of exploration. What we are privileged enough to do is going into the next new unexplored spaces,” says Berger.
A field of bones
In the first few days of the expedition, the biggest problem was knowing where to step.
“The first thing that you would see, especially in the early stages of the investigation, was just bones. Bone debris everywhere,” says K. Lindsay Hunter, an American scientist and one of the “astronauts” on the Rising Star expeditions, which were conducted in November 2013 and March 2014.
Marina Elliott, another of Berger’s astronauts, described the scene underground as “some of the most difficult and dangerous conditions ever encountered in the search for human origins.”
Some scientists in this field spend an entire career finding one fragment to identify a possible new species. But early on, the team knew they had stumbled onto something extraordinary.
Initially, Berger thought that they might find no more than a single skeleton. But he says that almost all the bones they found — besides a few rodent and bird remains that came into the cave much later — were from Homo naledi.
“We found everything from infants to babies to toddlers to teens, young adults, old individuals. It is like nothing that we could have ever imagined,” says Berger. “Homo naledi is already practically the best-known fossil member of our lineage.”
The team claims to have uncovered remains of at some 15 distinct individuals, but say this is only the beginning.
“The chamber has not given up all its secrets,” Berger says. “There are potentially hundreds if not thousands of remains of Homo naledi still down there.”
Berger says their discovery raises haunting questions about our deep past, and about our very identity. Many mysteries remain, and other scientists may well challenge some of the team’s controversial conclusions. But few will dispute that Homo naledi is truly significant.
Years of careful exploration lie ahead. “This was right under our nose,” says Berger. “And we didn’t see it. What else is out there?”