Some bones to pick
Let's be clear about something: the discovery of hominid bones in a cave at the Cradle of Humankind is a brilliant moment for science. Professor Lee Berger and his team have unearthed what has rightly been called a "treasure trove" of bones which enrich the search for answers about life before humans.Deputy President Cyril Ramaphosa gave a thumping speech about how the fossils proved that Africa was at the cutting edge of scientific endeavour. Afterwards, he lifted a replica of the skull to his lips for a kiss, perhaps because there weren't any babies at hand.The science on display on giant screens came courtesy of National Geographic magazine illustrations postulating about what might have been. A top "palaeoartist" had drawn likenesses of what was called a "new species", Homo naledi. One illustration imagined the scene when members of the clan threw a body down into the cave in a remarkable act of burial.Speculation that Homo naledi buried its dead was the centrepiece of Berger's presentation. The absence of carnivore tooth marks on the bones and the fact that the remains of no other species were found in the cave left only one conclusion: the bodies had been deliberately disposed of in the cave.As Ramaphosa and Berger pulled the blue cover off the display case of rather less-glamorous discovered bones, a phalanx of photographers snatched pictures and a battalion of television cameras rolled.By the end of the day, the entire world knew that a new species had been discovered in a cave in South Africa and that, incredibly, they buried their dead - challenging the long-held view that only Homo sapiens had done this.But there was something disturbing about the hype and the fervent nationalism that was summoned to announce this find to the world at Maropeng.There was only one moment during the press event when the giant bubble of hype was threatened by a sharp question. That occurred when David Smith of The Guardian newspaper asked Berger what he thought of the controversy over the bones. Some, he said, thought they were the remains of the already discovered Homo erectus.Berger dismissed his question with a laugh. There was no question that there were enough distinguishing features for this to be called a new species, he said.But Smith's question made me uncomfortable. Why had we not been told about this controversy? Why not lay out the contested facts and argue the merits of your version? Why not invite someone to present a challenge to the conclusions?My unease grew when I found out that there was, in fact, a great deal of controversy in the global scientific community over the bones. I bumped into Katharine Child, a journalist at The Times, at the launch. Later, she sent me questions she had sent to Professor Tim White, a palaeoanthropology professor at Berkeley, California.She asked him three questions, which I publish here with their answers:1. Is there enough evidence these creatures disposed of dead or do we just not know how they got into the chamber?White: Even the authors admit that there is insufficient evidence of this. Peer reviewers at Nature said the same thing, and rejected the paper. Peer reviewers at eLIFE said the same thing. That is why the publicity claims differ from what is actually reported in the scientific paper. This is speculation based on purely circumstantial evidence.2. Does it matter that Nature dismissed this paper?White: Yes, it matters. It is clear to see why Nature rejected the many manuscripts submitted to them, and post hoc explanation that this was because the papers were not compatible with Nature format is obfuscation of the fact that they failed to pass rigorous peer review.3. Do we know that these creatures are a new species without dating?White: Dating is irrelevant; these are a small, primitive H. erectus, whatever the date turns out to be. This is because they are not biologically different, in any significant way, from already known H. erectus found in places like Swartkrans (800m away), eastern Africa, or the Georgian republic. Of the 80+ traits listed in the e-LIFE supplemental material, only a small fraction of them are even claimed to differentiate these fossils from earlier described H. erectus, and that fraction of characters is known to vary among members of the same species (even population) of both H. erectus and H. sapiens. In other words, the newly described "species" is an example of artificial species inflation in palaeoanthropology.I was gobsmacked. Here was a top scientific authority questioning the claim that there was anything such as Homo naledi. To repeat, he described this as "an example of artificial species inflation in palaeoanthropology". And Nature had rejected "the many manuscripts submitted to them"?I wrote to him to ask if he would write something on Homo naledi for the Rand Daily Mail.He declined, saying: "What seems to be needed is more along the lines of investigative journalism than scientists complaining about the behaviour and conclusions of colleagues. The print and broadcast media are not the place for scientists to conduct debates over human anatomy. Indeed, this only provides additional collapse of science into entertainment."White was not alone in his scepticism. It was being published everywhere. Everywhere but in South Africa, where we were believers. A country awash with bad news was suddenly at the cutting edge of global science. Who would rain on that parade?There was some gentle prodding in the academic online journal The Conversation, where Darren Curnoe, a human evolution specialist at Australia's UNSW, asked: "Did the scientists rush the announcement for some reason? Why didn't they wait until they had an age estimate at hand before going to a journal? Are the geologists unable to date the fossils?"He went on: "My 'nonsense-filter' also tells me that all the talk in the media about this new species burying its dead and having human-like morality, or that it dismantles one of the key pillars of human uniqueness, needs to be called out for what it truly is: absurd."More scepticism came from Frans de Waal, writing in The New York Times: "The suggestion by some scholars that this requires belief in an afterlife is pure speculation. We simply don't know if Homo naledi buried corpses with care and concern or unceremoniously dumped them into a faraway cave to get rid of them."It is an odd coincidence that 'naledi' is an anagram of 'denial'. We are trying way too hard to deny that we are modified apes. The discovery of these fossils is a major palaeontological breakthrough. Why not seize this moment to overcome our anthropocentrism and recognise the fuzziness of the distinctions within our extended family?" he wrote.Deutsche Welle interviewed anthropologist Christoph Zollikofer, who said: "The idea that this is a new genus is just another headline grabber. About 90% of this publication addresses the media and not the scientific community. I call this a 'media species', which is usually quite short-lived."He went on to say: "My intuition says it is a primitive Homo erectus. But I'm just speculating, since nobody knows its exact biological age. Assuming that it is 2million years old, you could say it is an early Homo erectus, but not a new genus."Zollikofer was adamant, adding: "If you look more closely at the site where the skeletons were found, the cemetery theory becomes less probable. Think about it: according to the publication, there had never been direct access to the Dinaledi chamber, where the bones were found. So our prehistoric human had to climb down there, squeeze through the narrow cave in complete darkness while dragging a corpse belonging to a member of its own species. From a purely practical standpoint, that makes no sense whatsoever."While South Africa was blissfully unaware of the questions about Homo naledi, the scientific world, it seemed, was abuzz with them. Even the popular website BuzzFeed described the Nature rejection as "a diss widely discussed in palaeontology".By immersing a scientific discovery in a heady bath of populism, Berger and his crew had drowned the critical discourse that is essential to advancing knowledge. Before long, politicians had taken over and we were debating whether we believed humans came from baboons, whether the find was a "racist" slur on Africans. Science had been trampled in the great rush of hype and national pride.