Last Updated Thu, 07 Apr 2005 11:26:46 EDT
CBC News
WASHINGTON - The sunken-faced Toumai, or "old man of Chad," now appears to be more of a human ancestor than an ape, anthropologists say.
Michel Brunet of the University of Poitiers in France led the team that first described the seven-million-year-old specimen in 2002, which they consider to be a forerunner of Homo sapiens.
At the time, researchers weren't sure where to place it on the evolutionary tree – an anatomically human ancestor of hominids versus a chimp-like creature.
Now they've found new teeth and jaw fragments that illustrate the differences between Toumai, known scientifically as Sahelanthropus tchadensis, and apes.
Brunet hypothesized that the skull belongs on the earliest human branch.
Not all researchers agreed with his interpretation, saying the fossil showed both human features as well as a chimp-sized height.
Detractors also said the skull had too small a brain capacity to be a hominid.
Two studies published in the April 7 issue of the journal Nature tip the evidence in favour of Brunet's ideas, although the case isn't closed among paleontologists.
In one new study, the team reports the discovery of two new jaw fragments and the crown of a tooth.
The latest fossils were found in the same geographical area as the skull, namely the desert of northern Chad.
Researchers have now presented a computerized 3D reconstruction of the skull.
Scans confirm Toumai, meaning "hope of life" in the local Goran language, showed hominid features, such as skull angles and cranial capacity.
The position of the hole for the spinal cord also resembles ours, rather than apes, which suggests it walked upright, the team said.
If Toumai's bipedalism is confirmed, it could also change how researchers view the birthplace of humanity, shifting the ancestral home from the Great Rift Valley in present day Ethiopia and Kenya toward the more western side of the continent.
To clinch the walking idea, scientists would need to find and analyse skeletal bones such as knee or hip.
CBC News
WASHINGTON - The sunken-faced Toumai, or "old man of Chad," now appears to be more of a human ancestor than an ape, anthropologists say.
Michel Brunet of the University of Poitiers in France led the team that first described the seven-million-year-old specimen in 2002, which they consider to be a forerunner of Homo sapiens.
At the time, researchers weren't sure where to place it on the evolutionary tree – an anatomically human ancestor of hominids versus a chimp-like creature.
Now they've found new teeth and jaw fragments that illustrate the differences between Toumai, known scientifically as Sahelanthropus tchadensis, and apes.
Brunet hypothesized that the skull belongs on the earliest human branch.
Not all researchers agreed with his interpretation, saying the fossil showed both human features as well as a chimp-sized height.
Detractors also said the skull had too small a brain capacity to be a hominid.
Two studies published in the April 7 issue of the journal Nature tip the evidence in favour of Brunet's ideas, although the case isn't closed among paleontologists.
In one new study, the team reports the discovery of two new jaw fragments and the crown of a tooth.
The latest fossils were found in the same geographical area as the skull, namely the desert of northern Chad.
Researchers have now presented a computerized 3D reconstruction of the skull.
Scans confirm Toumai, meaning "hope of life" in the local Goran language, showed hominid features, such as skull angles and cranial capacity.
The position of the hole for the spinal cord also resembles ours, rather than apes, which suggests it walked upright, the team said.
If Toumai's bipedalism is confirmed, it could also change how researchers view the birthplace of humanity, shifting the ancestral home from the Great Rift Valley in present day Ethiopia and Kenya toward the more western side of the continent.
To clinch the walking idea, scientists would need to find and analyse skeletal bones such as knee or hip.
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