The skull may also radically change thinking on human evolution, by pushing back the period when the divergence between chimpanzees and humans occurred. Nicknamed “Toumai,” a name usually given to children born close to the dry season in Chad, scientists believe this hominid existed in the middle of a crucial interval in human evolution.
Brunet’s and Vignaud’s discovery, first found one year ago, will be published tomorrow in the scientific journal Nature. On Friday, the two will discuss their findings at a press conference in France. Chris Stringer, head of the human origins group in the department of paleontology at the Natural History Museum in London, is one of many researchers and scientists from around the world who considers Toumai a revolutionary find. He spoke to NEWSWEEK’s Suzanne Rozdeba about the discovery.
Chris Stringer: It’s very significant because it’s the only really complete skull we’ve got of something that at least relates to our origins in the period from about 6 to 7 million years ago. We’ve got fossil ape skulls from 8 or 9 million years ago. We have hominids from Africa from 3 to 4 million years ago. This is filling a gap where we really didn’t have much material. It comes from Chad, in Africa, an area which is very unexpected to be producing material like this. It makes us aware that the places we’ve been looking in East and South Africa for our earliest ancestors are probably not telling us the whole story. There are lots of other parts of Africa that have important evidence.
The skull is slightly distorted, so it’s not in perfect shape. Using computer technology, it will be possible to correct the distortion and get a much better image of what it looks like. As preserved, it’s relatively complete. It’s an apelike skull. It’s got a small brain, but the face does show some human features. It’s got small, canine teeth. The wear on those teeth, which is on the tip, is unusual for apes. That could be taken as a humanlike feature.
The sex of the specimen is a tricky issue. It’s got a strong brow ridge, which would certainly suggest its male. But on the other hand, it’s got small canine teeth, and there’s no crest on the top of the skull. That might suggest it’s a female. I don’t think it’s certain that it’s a male. We would imagine that if it were a male, it would have larger canine teeth, a face that’s larger and perhaps less human-looking.
It’s assumed the creature was fundamentally apelike in its way of life, in its feeding, in its behavior. But whether it walked upright? We can’t be sure. My guess is, this creature was still spending time in the trees. I think it’s difficult to go beyond that at the moment. We don’t have the rest of the skeleton of this creature.
I think it’s difficult to say the exact position of this find. It’s something completely new and has an unexpected combination of characters. I think it’s right to be cautious. It might be an ancestor of ours. But we’ve got to bear in mind that in this period, about 6 to 7 million years ago, they could be ancestors for us, they could be ancestors for the chimpanzees, they could be ancestors for the gorilla. They might also be parallel lines that actually have died out. When you’ve only got a single find like this from an unexpected place such as Chad, I think it’s going too far to assume we can place it, with confidence, in any part of the tree of evolution.
I think it is too soon to know how significant this is. A lot more study will be needed with this material. One would like to see an undistorted version of the skull, constructed by computer technology. Studies of the teeth [are needed] so that we can get a better fix on its diet. One hopes [we will discover] postcranium material that will help us to establish whether this creature walked upright. It’s still early to asses its significance. It is, because of its completeness and where it comes from and its age, it is an important find. But how important, I think it’s too early to say.
