The oldest known skeleton of an assumed human ancestor has been unveiled. The female creature is named Ardipithecus ramidus (known as Ardi for short) and has been dated at 4.4 million years old. Scientists say they need more fossil finds before they are able to say that Ardi is definitely a direct human ancestor.
Chimpanzee Characteristics Appear in Remains
Ann Gibbons reporting for ScienceNOW Daily News (October 1, 2009) writes that Ardi “had a brain and body the size of a chimpanzee, it did not knuckle-walk or swing through the trees like an ape.” In fact, Ardi walked upright, although the presence of an opposable toe says she also spent plenty of time in trees.
The research team has determined this from some of the key bones they recovered from a site in Ethiopia in 1992. The bones found include the skull with teeth, arms, hands, pelvis, legs, and feet. The dig also turned up fragments from what may be 35 other individuals.
Ardi Adds to the Information from Lucy
In 1974, paleontologist Donald C. Johanson found a skeleton in Hadar, Ethiopia. Named Lucy by the team that found her, the proper scientific appellation is Australopithecus afarensis, and she has been dated to 3.2 million years old.
According to National Geographic (September 20, 2006) “With a mixture of ape and human features - including long dangling arms but pelvic, spine, foot, and leg bones suited to walking upright - slender Lucy stood three and a half feet (107 centimeters) tall."
Lucy’s discovery nailed the question of whether or not human ancestors walked upright before they evolved big brains – they did.
Study of Skeleton a Long Process
Professor Tim White from the University of California, Berkeley is one of the lead scientists on the project, said the investigation of the fossilized bones had been painstaking.
He told the journal Science, “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.”
Is Ardi the Missing Link?
Since Charles Darwin postulated evolution in his book Origin of the Species in 1859, scientists have been looking for a common ancestor between humans and the great apes.
Science reporter Jonathan Amos at BBC News (October 1, 2009) writes that “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 this common ancestor may have existed much further back in time…”
The missing link may be as far as back seven or nine million years ago.
