A new type of ancient hominid has been discovered in a cave in South Africa, scientists reported on Thursday. Moreover, it seems that like ancient humans, and Neanderthals, this previously unknown being ritualistically buried its dead.
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The new species - described in the scientific journal eLife - has been named Homo naledi, in honour of the Rising Star cave where it was found. Naledi means "star" in Sesotho.
Luckily, in contrast to the frustratingly rare fossils of Denisovan hominids found in Eurasia, this African cave yielded a fossilized treasure trove of some 1,500 fragments from 15 individuals, ranging from infants to adults. This was the biggest single find of fossil hominid bones in Africa.
When Homo naledi lived is not clear. The discovered remains cannot be dated, say the archaeologists studying the cave, because the bodies seem to have been deliberately moved into the deep inner part and were therefore not lying within an indicative soil layer. There are also no fossils with them from other animals that could provide clues.
"But we can see from their physical morphology or appearance where their species originates in time. If our present understanding is correct, then that must be in excess of 2.5 million years," said Lee Berger of the Evolutionary Studies Institute at Johannesburg's University of the Witwatersrand.
So, was it a human precursor? We cannot know, but clearly we all had common ancestors: naledi developed at or near the root of the Homo group, Berger says.
Walk like a man, think otherwise
Modern man is believed to have split off from his nearest fellow hominins about 200,000 years ago, going by skeletons found in Ethiopia showing the beginnings of cranial changes associated with moderns, including a rounder skullcase and the projecting human chin.
Not so the Homo naledi, which is believed to have walked upright like man, and to therefore have hands and feet that looked human – but its brain wasn't much bigger than that of a chimpanzee. Its shoulders also had an apelike aspect, the researchers said.
However old they were, if they did indulge in burial, it could be indicative of identification, ritual, possibly spiritual belief. "[It] indicates to us that they were seeing themselves as separate from other animals and in fact perhaps from the natural world," said Berger.
If they'd been hunted down
Paleoanthropologists concluded that Homo nalendi buried its dead less through finding graves and more through deduction.
First of all, the bones were found in a deep cave near the famous sites of Sterkfontein and Swartkrans, some 50 km northwest of Johannesburg, which have been yielding hominin remains for decades.
Virtually no other remains from other species were found there. Nor did the bones show evidence of claw or tooth marks, which they would have done, if they had been hunted and eaten by animals living in the cave.
"It does appear after eliminating all other possibilities that Homo naledi was deliberately disposing of its body in a repeated fashion," Berger said.
Which does not necessarily mean the dead were "buried", complete with ritual. Berger however finds more support for the theory because the skeletons were found in splendid specietal isolation, not with remains of other animals. Ergo the Homo naledi were not merely throwing dead bodies down a hole to keep off lions and hyenas: if that were the case they'd throw other remains that could attract predators down there too, Berger argues.
It bears noting that the archaeologists offer a gruesome alternative hypothesis to burial: the deep cave may have been a "death trap" where the naledis got stuck and died.
In the case of the caring Neanderthals, not only did they apparently bury the dead – like modern man, they did so with flowers. Evidence from the La Chapelle-aux-Saints cave in France, where Neanderthals flourished 60,000 years ago shows they were doing so before the arrival of modern man in the region, ergo Neanderthal s didn't learn it from us.
Yet again, the evidence was circumstantial and included the absence of predation marks on the bones, which indicated that the dead bodies had been disposed of with care. Animal remains found in the cave had been gnawed on.
The surrounding area is a U.N. World Heritage site, named the "Cradle of Humankind" by the South African government because of its rich collection of hominin fossils.