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Fossil finds extend human story Fossil finds extend human story
(20 minutes later)
An ancient human-like creature that may be a direct ancestor to our species has been described by researchers.An ancient human-like creature that may be a direct ancestor to our species has been described by researchers.
The assessment of the 4.4-million-year-old animal called Ardipithecus ramidus is reported in the journal Science.The assessment of the 4.4-million-year-old animal called Ardipithecus ramidus is reported in the journal Science.
Even if it is not on the direct line to us, it offers new insights into how we evolved from the common ancestor we share with chimps, the team says.Even if it is not on the direct line to us, it offers new insights into how we evolved from the common ancestor we share with chimps, the team says.
Fossils of A. ramidus were first found in Ethiopia in 1992, but it has taken 17 years to assess their significance.Fossils of A. ramidus were first found in Ethiopia in 1992, but it has taken 17 years to assess their significance.
The most important specimen is a partial skeleton of a female nicknamed "Ardi".The most important specimen is a partial skeleton of a female nicknamed "Ardi".
If Ardipithecus ramidus was not actually the species directly ancestral to us, she must have been closely related to it The Ardipithecus project teamIf Ardipithecus ramidus was not actually the species directly ancestral to us, she must have been closely related to it The Ardipithecus project team
The international team has recovered key bones, including the skull with teeth, arms, hands, pelvis, legs, and feet.The international team has recovered key bones, including the skull with teeth, arms, hands, pelvis, legs, and feet.
But the researchers have other fragments that may represent perhaps at least 36 different individuals, including youngsters, males, and females.But the researchers have other fragments that may represent perhaps at least 36 different individuals, including youngsters, males, and females.
One of the lead researchers on the project, Professor Tim White from the University of California at Berkeley, said the investigation had been painstaking.One of the lead researchers on the project, Professor Tim White from the University of California at Berkeley, said the investigation had been painstaking.
"It took us many, many years to clean the bones in the National Museum of Ethiopia and then set about to restore this skeleton to its original dimensions and form and then study it and compare it with all the other fossils that are known from Africa and elsewhere as well as with the modern age," he told the journal."It took us many, many years to clean the bones in the National Museum of Ethiopia and then set about to restore this skeleton to its original dimensions and form and then study it and compare it with all the other fossils that are known from Africa and elsewhere as well as with the modern age," he told the journal.
It has been a 17-year investigation to assess the discoveriesIt has been a 17-year investigation to assess the discoveries
"This is not an ordinary fossil. It's not a chimp. It's not a human. It shows us what we used to be.""This is not an ordinary fossil. It's not a chimp. It's not a human. It shows us what we used to be."
The fossils come from the Middle Awash study area in the Afar Rift, about 230km northeast of Addis Ababa, Ethiopia's capitol.The fossils come from the Middle Awash study area in the Afar Rift, about 230km northeast of Addis Ababa, Ethiopia's capitol.
Some of the characteristics of the animal's skeleton are said to echo features seen in very ancient apes; others presage traits seen in later, more human-like species.Some of the characteristics of the animal's skeleton are said to echo features seen in very ancient apes; others presage traits seen in later, more human-like species.
The scientists say Ardi was good at climbing trees but also walked on two feet. However she did not have arched feet like us, indicating that she could not walk or run for long distances. The scientists say 1.2m-high (4ft) Ardi was good at climbing trees but also walked on two feet. However she did not have arched feet like us, indicating that she could not walk or run for long distances.
What is surprising about the discovery is that the remains were found in what would have been a forested area 4.4 million years ago. It had been thought that early human evolution was driven, if only in part, by the disappearance of trees - encouraging our ancestors to walk on the ground.What is surprising about the discovery is that the remains were found in what would have been a forested area 4.4 million years ago. It had been thought that early human evolution was driven, if only in part, by the disappearance of trees - encouraging our ancestors to walk on the ground.
"These creatures were living and dying in a woodland habitat, not an open savannah," said Professor White."These creatures were living and dying in a woodland habitat, not an open savannah," said Professor White.
Because of its age, Ardipithecus is said to take science closer to the yet-to-be-found last common ancestor with chimps, our close genetic relatives.Because of its age, Ardipithecus is said to take science closer to the yet-to-be-found last common ancestor with chimps, our close genetic relatives.
And because many of Ardipithecus' traits do not appear in modern-day African apes, it suggests that common ancestor may have existed much further back in time than had previously been supposed - perhaps seven or nine million years ago.And because many of Ardipithecus' traits do not appear in modern-day African apes, it suggests that common ancestor may have existed much further back in time than had previously been supposed - perhaps seven or nine million years ago.
Comparisons with modern chimp and gorilla anatomy also underline just how much these African apes themselves have evolved since parting company with the line that led eventually to modern humans.Comparisons with modern chimp and gorilla anatomy also underline just how much these African apes themselves have evolved since parting company with the line that led eventually to modern humans.
Asked whether A. ramidus was our direct ancestor or not, the team said more fossils from different places and time periods were needed to answer the question.Asked whether A. ramidus was our direct ancestor or not, the team said more fossils from different places and time periods were needed to answer the question.
"We will need many more fossil recoveries from the period of 3-5 million years ago to confidently answer that question in the future," the scientists said in a briefing document that accompanied their journal papers."We will need many more fossil recoveries from the period of 3-5 million years ago to confidently answer that question in the future," the scientists said in a briefing document that accompanied their journal papers.
"But if Ardipithecus ramidus was not actually the species directly ancestral to us, she must have been closely related to it, and would have been similar in appearance and adaptation."But if Ardipithecus ramidus was not actually the species directly ancestral to us, she must have been closely related to it, and would have been similar in appearance and adaptation.
Jonathan.Amos-INTERNET@bbc.co.ukJonathan.Amos-INTERNET@bbc.co.uk