I got up all bleary-eyed this morning, and before I got my first sip of coffee, the first thing I saw, blasted across Twitter and all the popular news sites, was the news that a new species of human, Homo naledi has been discovered in South Africa. They have the partial skeletons of 15 different individuals, over 1500 bones, all recovered from a single cave. They’re calling it a new and unique species, and further, they’re claiming that the site is a ritual burial chamber.
Whoa. Brain is whirling. This thing is all over the net, over night. Better drink more coffee.
OK, that’s better.
I’m a little put off by the abrupt and sensationalist appearance in pop news sites, but here’s the science paper. It’s published in eLife, an interesting journal I’ve written about before. It’s peer-reviewed, the lead authors have a respectable reputation, and it looks legit. It’s a real discovery: a cache of bones in a very difficult-to-reach, sheltered site. One of the fascinating bits of the story is that the cave is so inaccessible, reached through such narrow crevices, that all the bones were recovered by a team of women who were small enough to fit.
No matter what, this is an impressive and exciting discovery. A whole small population of individuals, all found in one place? There are years of analysis waiting to be done. Here’s the holotype and the large collection of bones used in the first publication. Homo naledi is a small-brained, bipedal hominin, that’s for sure.
Now for my reservations.
The researchers haven’t yet dated the specimens! We don’t even have a guess! That’s how preliminary this publication is. I can sort of understand wanting to get an exciting find like this published as soon as possible, but I have no idea where to place this species in the family tree now. Is it 3 million years old, or 300 thousand?
It’s been labeled as a new species, but is it? I’m not an expert on human evolution by any means, but it looks like it fits within the parameters of Homo erectus, and the authors note its close resemblance to H. erectus, but also insist that there are small, unique features to the skull. I’d want to see more input from other experts. It’s always tempting to slap a new species name on a new specimen, but I’d be just as thrilled if this turned out to be a comprehensive assemblage of a H. erectus group.
The news stories are all speculating that this is a ritual burial site, suggesting that our ancestors had certain cultural practices long before we expected. We can’t say anything about the timing, because we don’t know how old the site is! But there are some suggestive details. The cave is extremely hard to access (although we don’t know anything about accessibility when the cave was in use), and most interestingly, only H. naledi bones are found in the cave. That suggests it was not simply a rubbish pit, or that animal remains naturally washed into it. Ritual burial seems like a good explanation, except that these people had brains the size of an orange.
Most of the coverage right now seems gushing and uncritical, but I recommend the article in the Guardian, which has a good balance of enthusiasm and skepticism. I think it’s a great day for the science of human evolution, but the full details are going to take much longer and much more work to emerge. I’m looking forward to further reports. The world had better fund more anthropology/paleontology research so I don’t have to be kept waiting!