Posted on 04/06/2005 10:43:45 AM PDT by Vaquero
Experts: Fossil Apparently Human Ancestor
20 minutes ago Science - AP
By MALCOLM RITTER, AP Science Writer
New fossil finds and a computer skull reconstruction bolster the case that an ancient creature that grabbed headlines in 2002 really is the earliest known ancestor of modern humans, researchers say.
Toumai ping!
Here's the full article:
New fossil finds and a computer skull reconstruction bolster the case that an ancient creature that grabbed headlines in 2002 really is the earliest known ancestor of modern humans, researchers say.
In that year, scientists announced finding jaw fragments, some isolated teeth and a skull of a creature nicknamed "Toumai" in Chad. At some 6 million to 7 million years old, the fossils came from around the time of a major split in the evolutionary tree, with one branch leading eventually to humans and the other branch leading to chimps.
The researchers argued that the creature, which they dubbed Sahelanthropus tchadensis, belongs on the human branch and so is the oldest known hominid. Some others disagreed. In any case, the skull provided a puzzling combination of human and chimp traits and raised what one expert called "a wheelbarrow full of questions" about evolution at that time.
Many scientists now think S. tchadensis was probably a hominid, and more evidence appears in Thursday's issue of the journal Nature. It comes from Michel Brunet of the University of Poitiers in France, who led the team that made the original discovery, and colleagues.
Other experts said the new work strengthens the case for hominid status but doesn't clinch it.
"This isn't a smoking gun," said David Begun of the University of Toronto.
A big question is whether S. tchadensis walked upright, because that's a key characteristic of hominids. Brunet, in an e-mail, said given the available evidence it would be a "great surprise" if it didn't walk upright. But he agreed with other scientists that to be sure, scientists would have to find and analyze skeletal bones that carry signatures of upright walking, like a knee, hip or foot.
In Nature, Brunet and colleagues report discovering two new jaw fragments and the crown of a tooth in the same geographical area as the earlier findings. Analysis shows similarities to hominid fossils and differences from ape traits, they said.
They also present a computerized reconstruction of the skull, because the fossil had been distorted in the ground. The reconstruction confirms that S. tchadensis shared several features with later hominids, the researchers wrote. In addition, the position of the hole where the spinal cord enters is like what's seen in humans but not apes, which suggests upright walking, they wrote.
Rick Potts, director of the Human Origins Program at the Smithsonian Institution's National Museum of Natural History, said the position of that hole doesn't necessarily prove S. tchadensis walked upright. Still, Potts said he thinks the creature was probably a hominid.
Begun agreed, and said the chances are "pretty good" the creature walked upright, although "I'll be convinced when they find a knee joint."
Bernard Wood of George Washington University said he finds too little evidence to declare S. tchadensis a hominid with certainty, although it might well be true. If it isn't, the creature might have belonged to a branch of the evolutionary tree that has no living representatives, he said.
No fossils in my family tree.
Those fossils aren't of a human, they are part of the remains of Jimmy Hoffa.
as you wish.
since when is Giant stadium in Africa????
Don't you know, Hoffa was sliced into thousands of pieces and distributed over the globe.
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"We only arrived 2 generations ago so not time to fossilize."
Me too! How's GrandPappy doin' these days?
*sigh*
So why do humans have a backbone that connects to the skull like that of a bear instead of a chip?
"Don't you know, Hoffa was sliced into thousands of pieces and distributed over the globe."
There was a little bit of Jimmy in every can of tuna fish sold for a while.
I've never heard that before. Do you have a source for the statement?
Chocolate chip or fish-and-chip?
That explains the excess oil and foul odor.
You see, human beings are the pinnacle of evolution - we have the best parts of every animal. :-) /sarcasm
I like how they hid the skull in the deepest, darkest part of Africa.
I believe there is a handful of dirt in my direct ancestry - God evolved my ancestors into Humans without the need for monkeys - in fact, he let the first male in my family tree name the monkeys along with the other beasts...
Because we evolved an upright stance so we could carry 'piKiniK' baskets.
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