He had a small face, small teeth, a narrow head, a very heavy brow and he could be your oldest ancestor.
A team of French and Chadian researchers announced today they have found the skull, jaw fragments and teeth of a six million to seven million-year-old relative of the human family. The find, which is the oldest human relative ever found, suggests humans may have begun evolving from chimpanzees sooner than researchers realized.
It also implies that human evolution may have been a much messier process than imagined.
"What this does is say 'Hey, where humans are connected to the tree of life is not a simple connection,'" says Bernard Wood, an anthropologist at George Washington University.
The skull's human-like face and teeth are surprising since they come from a period when researchers believed human ancestors just began evolving. Many expected a specimen as old as this one — named Toumaï — to appear more chimp-like.
Instead, Wood explains, species like the Chad discovery may have been among several early versions of human ancestors. That would mean the tree of life may be more "bushy" than tree-like, with several branch species diverging from the ancestral line.
A Life's Work
An international team led by French paleontologist Michel Brunet found the unusually complete skull, two lower jaw fragments and three teeth last year in Chad, Central Africa. Brunet, who has spent the last 25 years searching in the region, delayed announcing the discovery since he first wanted to consult with colleagues and ensure his estimations of the specimen were accurate.
"It's a lot of emotion to have in my hand the beginning of human lineage," Brunet told Nature magazine, where his reports about the skull appear this week. "I have been looking for this for so long."
The skull shows both chimp and human-like features, but is clearly a member of the hominid family — the family including species more closely related to humans than chimpanzees. Brunet called the find Sahelanthropus tchadensis — referring to the discovery site in Chad, in Africa's Sahel region and nicknamed it "Toumaï," "hope of life" in Africa's Goran language.
Whether Toumaï is a direct ancestor of humans remains to be seen and may be unlikely.
"I have my doubts this is our direct ancestor simply because the first time someone puts their hand in a pie, they're not likely to pull out the plum," says Wood.
The "pie," so to speak, is the time period of six million to seven million years ago.
Vital Piece of the Puzzle
The well-preserved skull of Toumaï adds valuable information to a time period in human evolution that is still fuzzy. Archaeological evidence suggests the world was populated by apes 10 million years ago, then fairly complete fossil records show early ancestors of humans began appearing on the scene about five million years ago.
Few fossils have filled in the gap between these two time periods.
Scientists had assumed that human ancestors began splitting from chimpanzees about five million to seven million years ago, based on genetic evidence. Toumaï's appearance pushes that timeline back and suggests that nature may have begun experimenting with human evolution at least a couple of million years earlier.