Ardi the ape-woman described in ScienceNOW, BBC News and e! Science News, 1 Oct 2009, and Science, vol. 326, pp36-40 & 75-86, 2 Oct 2009.
An international team of researchers has found a partial skeleton of a creature named Ardipithecus ramidus, nicknamed Ardi, in the Middle Awash region in Ethiopia. Isolated bones, bone fragments and teeth of Ardipithecus have been found since the early 1990s but this specimen is the most complete. The new specimen consists of a partial skull, some teeth, two vertebrae, forearm and hand bones, pelvic bones, part of a thigh bone, lower legs bones and foot bone. The bones are very fragile, broken into many fragments and “very poorly fossilised”. On the basis of their reconstruction the research team believe Ardipithecus was “as big as a chimpanzee and had a brain size to match.” It had a flat foot with the big toe separated from the other toes, like a thumb, as seen in living apes, indicating it was good at grasping tree branches with its feet, but not good at walking on the ground, and it could not run on two feet like human. It had an opposable thumb and a flexible wrist, indicating it was not a knuckle walker like a chimpanzee or gorilla.
The badly fragmented pelvis was reconstructed by Owen Lovejoy of Kent State University, Ohio, who used models and CT scans of the original specimens to build a model. According to Science, he is “satisfied that the 14th version of the pelvis is accurate.” On the basis of his reconstruction he claims the pelvis is shorter and broader than living apes, and therefore the spine was long and curved like a human spine, and Ardipithecus would have walked upright. Lovejoy told BBC News: “She has opposable great toes and she has a pelvis that allows her to negotiate tree branches rather well. So half of her life is spent in the trees; she would have nested in trees and occasionally fed in trees, but when she was on the ground she walked upright pretty close to how you and I walk.” The researchers have also collected many fossils of other animals and plants from the area, including birds, mammals, invertebrates, wood and pollen.
According to Science: “From these specimens, they conclude that Ardi lived in a woodland, climbing among hackberry, fig, and palm trees and coexisting with monkeys, kudu antelopes, and peafowl. Doves and parrots flew overhead. All these creatures prefer woodlands, not the open, grassy terrain often conjured for our ancestors.” This does not fit with the story that human ancestors evolved upright walking as the woodlands were replaced by open savannah grasslands, forcing evolving apes to walk on the ground, but according to Tim White from the University of California, Berkeley “These creatures were living and dying in a woodland habitat, not an open savannah.”
The Ardipithecus bones are dated at 4.4 million years old, making them 1.2 million year older than “Lucy”. Many researchers believe this creature was close to the common ancestor of chimps and humans. Owen Lovejoy commented: “People often think we evolved from apes, but no, apes in many ways evolved from us. It has been a popular idea to think humans are modified chimpanzees. From studying Ardipithecus ramidus, or ‘Ardi,’ we learn that we cannot understand or model human evolution from chimps and gorillas.” Tim White commented: “This is not an ordinary fossil. It’s not a chimp. It’s not a human. It shows us what we used to be.”
BBC e! Science News
Editorial Comment: The fragmentary nature of all the Ardipethicus finds, and Owen Lovejoy’s 14 attempts at reconstructing the pelvis from numerous small fragments, also reminds us that much guesswork goes into putting those fragments together. As this creature is extinct, how is Lovejoy to know which of his 14 guesses was right? We suspect he chose the one that fitted his evolutionary story best. Lovejoy has a history of reconstructing pelvis bones to suit evolutionary stories. He reconstructed the pelvis of another famous “pithecus” – Lucy, whose pelvis was also in fragments. The following is from the transcript of a TV programme entitled In Search of Human Origins, Part One, broadcast on PBS 3 June 1997.
OWEN LOVEJOY: When I put the two parts of the pelvis together that we had, this part of the pelvis has pressed so hard and so completely into this one that it caused it to be broken into a series of individual pieces, which were then fused together in later fossilization.
DON JOHANSON: After Lucy died, some of her bones lying in the mud must have been crushed or broken, perhaps by animals browsing at the lake shore.
OWEN LOVEJOY: This has caused the two bones in fact to fit together so well that they’re in an anatomically impossible position.
DON JOHANSON: The perfect fit was an allusion (sic) that made Lucy’s hip bones seems to flair out like a chimps. But all was not lost. Lovejoy decided he could restore the pelvis to its natural shape. He didn’t want to tamper with the original, so he made a copy in plaster. He cut the damaged pieces out and put them back together the way they were before Lucy died. It was a tricky job, but after taking the kink out of the pelvis, it all fit together perfectly, like a three-dimensional jigsaw puzzle. As a result, the angle of the hip looks nothing like a chimp’s, but a lot like ours. Anatomically at least, Lucy could stand like a human.
Editorial Comment (continued): Having said all the above, we do partly agree with Tim White. Ardipithecus is not a chimp or a human being. All the evidence really shows is that Ardipithecus was just another ape, not what human beings used to be. Tim white’s assessment of the fossil is a clear case of imposing an evolutionary idea on the evidence, and Owen Lovejoy’s statement reminds us that no-one has seen an ape turn into a human so it is quite arbitrary as to where you put them on the evolutionary tree. The fact that this creature is different from any living ape and is now extinct does not prove it evolved into a human being. It proves it is a very dead ape. Even if this creature did walk upright in trees, that is no evidence it was evolving into a human. Living orangutans walk with an upright stance in trees, steadying themselves by grasping branches with their hands. No-one claims that they are evolving into people. In fact, orangutans are considered to be furthest from humans in the Great Ape evolutionary tree.