There was huge excitement in South Africa, and the world, this morning as we turned on our televisions and radios to hear what historically important announcement was to be made. We were not disappointed – a new species of hominin has been discovered at Maropeng, the Cradle of Humankind
The initial discovery was made in 2013 in a cave known as Rising Star in the Cradle of Humankind World Heritage Site, about 50km northwest of Johannesburg, by Wits University scientists and volunteer cavers. It was a well-kept secret among a group of 50 scientists from around the world, until today when the findings were revealed to the world. Consisting of more than 1 550 numbered fossil elements, the discovery is the single largest fossil hominin find yet made on the continent of Africa.
The new species is called Homo naledi, after the cave in which it was discovered. H. naledi was named after the Rising Star cave — “naledi” means “star” in Sesotho.
What is especially amazing about this species is that it buried its dead and was a tool-making ape – something never found previously.
The fossils have not been dated – so there’s more excitement to come.
“With almost every bone in the body represented multiple times, Homo naledi is already practically the best-known fossil member of our lineage,” said Lee Berger, research professor in the Evolutionary Studies Institute at the University of the Witwatersrand and a National Geographic Explorer-in-Residence, who led the two expeditions that discovered and recovered the fossils.
“This is a tremendously significant find,” said Terry Garcia, the National Geographic Society’s chief science and exploration officer. “That is why, when National Geographic received a call from Lee Berger reporting the fossils’ initial discovery, we immediately committed our support to this remarkable effort.”
The research shows that on average H. naledi stood approximately 1.5 metres tall and weighed about 45kg. H. naledi’s teeth are described as similar to those of the earliest-known members of our genus, such as Homo habilis, as are most features of the skull. The shoulders, however, are more similar to those of apes.
“The hands suggest tool-using capabilities,” said Dr Tracy Kivell of the University of Kent in the UK, who was part of the team that studied this aspect of H. naledi’s anatomy. “Surprisingly, H. 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 H. naledi’s feet.
Its feet, combined with its long legs, suggest that the species was well-suited for long-distance walking. “The combination of anatomical features in H. naledi distinguishes it from any previously known species,” added Berger.
Perhaps most remarkably, the context of the find has led the researchers to conclude that this primitive-looking hominin may have practiced a form of behaviour previously thought to be unique to humans.
The fossils – which consist of infants, children, adults and elderly individuals – were found in a room deep underground that the team named the Dinaledi Chamber, or “Chamber of Stars”.
That room has “always been isolated from other chambers and never been open directly to the surface,” said Dr Paul Dirks of James Cook University in Queensland, Australia, lead author of the eLife paper on the context of the find. “What’s important for people to understand is that the remains were found practically alone in this remote chamber in the absence of any other major fossil animals.”
So remote was the space that out of more than 1 550 fossil elements recovered, only about a dozen are not hominin, and these few pieces are isolated mouse and bird remains, meaning that the chamber attracted few accidental visitors.
“Such a situation is unprecedented in the fossil hominin record,” Hawks said.
The team notes that the bones bear no marks of scavengers or carnivores or any other signs that non-hominin agents or natural processes, such as moving water, carried these individuals into the chamber.
“We explored every alternative scenario, including mass death, an unknown carnivore, water transport from another location, or accidental death in a death trap, among others,” said Berger.
“In examining every other option, we were left with intentional body disposal by Homo naledi as the most plausible scenario.”
This suggests the possibility of a form of ritualised behaviour previously thought to be unique to humans. (In this context, “ritualised” refers to repeated behaviour.)
More than 50 experienced scientists and early-career researchers came together to study and analyse the treasure trove of fossils and to compose scientific papers.
Much remains to be discovered in the Rising Star cave. “This chamber has not given up all of its secrets,” Berger said.
“There are potentially hundreds if not thousands of remains of H. naledi still down there.”
“If we learned about a completely new form of hominin only because a couple of cavers were skinny enough to fit through a crack in a well-explored South African cave, we really don’t have a clue what else might be out there,” National Geographic Executive Editor for Science Jamie Shreeve writes in National Geographic magazine.
An in-depth feature.