A new relative of Homo sapiens was unveiled to the international media in the Cradle of Humankind near Johannesburg yesterday.
A new relative of Homo sapiens was unveiled to the international media in the Cradle of Humankind near Johannesburg yesterday.
Wits University’s Professor, Lee Berger, said the new species, Homo naledi, is a significant discovery that is already providing far-reaching insights into the origins of our genus.
He revealed the discovery to a packed auditorium at the Maropeng Visitors’ Centre in the Cradle of Humankind World heritage Site. The audience included Gauteng acting Premier, Lebogang Maile, and South African Deputy President, Cyril Ramaphosa who described the announcement as “as one of those moments in which the world learnt something new and remarkable”.
The Wits team, with the support of the National Geographic Society, has recovered more than 1 500 fossilised bones from at least 15 individuals of the same species. Berger said, “with almost every bone in the body represented multiple times, Homo naledi is already practically the best-known fossil member of our lineage”.
The individuals include males and females – some had only recently been born while others were in their mid-forties when they died.
The scientists have not yet been able to determine the age of the fossil treasures, but the appearance of the skeleton suggests that Homo naledi is one of the earliest members of our genus.
Some critics have expressed frustration at the apparent lack of an attempt to estimate how old the bones are. Berger explains that it has been difficult to calculate the age of the bones because they were found in soft sediments where they had been re-deposited since they were originally laid down.
He added that the almost complete absence of other animal bones in the cave made it impossible to place the fossils in a period when the animals were known to have lived.
Berger expects that direct tests of the fossil material will be able to determine the age range the bones.
Homo naledi was much smaller than humans are today with the average adult measuring 1.5 metres tall and weighing only about 45kg. Their skeletons were similar to ours and are clearly closer to humans than to chimpanzees, but their finger and toe bones were somewhat curved which would have made it easier for them to climb trees.
The fossil skulls are notably smaller than those of modern humans leaving considerably less space for their brains. The braincases of Homo naledi were measured at around 500 cubic centimetres, putting it into the same range as chimpanzees and considerably less than Homo sapiens with over 1300cc.
The discovery of Homo naledi skeletons deep underground in the Rising Star cave system has raised many important questions, including – how did they get there?
Berger was not able to provide direct evidence to answer this question, but through a process of deduction, was able to eliminate a number of possibilities and came up with an intriguing conclusion. He said there was no evidence to show that they had lived there or that their bones had been taken into the cave by predators or through water action.
The absence of a hole or a crevice in the surface where individuals could have fallen into the cave was eliminated because, normally under such circumstances animals would also have fallen into the cave. In this case, only the bones of Homo naledi were found.
Berger concluded that the only way the skeletons could have reached the underground chamber would have been if other individuals had put them there in a kind of burial ceremony.
He said that it would have been quite difficult to get the bodies into the cave because it would have entailed an arduous climb and an awkward descent through a narrow fissure.
If his conclusion that they were buried proves to be correct, it will force us to reassess the cognitive abilities of early hominins, as currently it is believed that only Homo sapiens and Neanderthals buried their dead.
Berger was clearly bursting with joy at the impact of his discovery, but he told the audience that there was still a lot more to come.
Slim pickings
Steven Lang
When Prof Lee Berger, a largish man, decided to go ahead with exploring the Rising Star cave system he knew would need a special set of skills. He also knew that the skills would have to come in rather slim packages so he circulated an advert on Facebook.
It listed he obvious scientific skills because he knew that a lot of specialised expertise would be necessary.
He sought out students, still early in their careers because tight budgets made for only minimal compensation and he expressed a preference for the ‘petite’ – not a usual requirement for scientific research.
‘Petite’ was a requirement because access to the Dinaledi Chamber of the Rising Star cave system is very restricted. The only entrance to the chamber is about 90 metres from the cave entrance. To get to the chamber researchers, or ‘underground astronauts’ as Berger refers to them, have to make their way through the ‘Superman’s Crawl’ which is only 27cm high then scale the Dragon’s Back before dropping into an 18cm-wide fissure which leads to the Dinaledi Chamber.
