Is this the missing link for humans?
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| Photo credit: Xijun Ni |
Science Recorder | Rick Docksai | Thursday, June 06, 2013
Scientists agree that humans first emerged in Africa, but a few
scientists think that their primate ancestors did a lot of evolving in
Asia first before making their way over to Africa. These researchers
argue that the recent discovery of a tiny 55-million-year-old primate
fossil in China adds their point of view some crucial supporting
evidence. The ancient primate, dubbed Archicebus Achilles, could be the oldest cousin of our species ever found.
Led by Xijun Ni of the Institute of Vertebrate Paleontology and Paleoanthropology (IVPP) at the Chinese Academy of Sciences in Beijing, the research team announced that this tree-dwelling fossil is in fact the oldest, most complete skeleton ever discovered. According Northern Illinois University anthropologist Dan Gebo, a co-author on the study, the fossil is one of the most primitive primate fossils ever documented.
A Chinese farmer found the fossil ten years ago in a slab of slate in eastern China’s Jingzhou area, just south of the Yangtze river. The primate’s body, which measured only three inches in length, exhibited distinctive physical characteristics that resemble those of us humans and of some of our closest modern-day monkey cousins.
Led by Xijun Ni of the Institute of Vertebrate Paleontology and Paleoanthropology (IVPP) at the Chinese Academy of Sciences in Beijing, the research team announced that this tree-dwelling fossil is in fact the oldest, most complete skeleton ever discovered. According Northern Illinois University anthropologist Dan Gebo, a co-author on the study, the fossil is one of the most primitive primate fossils ever documented.
A Chinese farmer found the fossil ten years ago in a slab of slate in eastern China’s Jingzhou area, just south of the Yangtze river. The primate’s body, which measured only three inches in length, exhibited distinctive physical characteristics that resemble those of us humans and of some of our closest modern-day monkey cousins.
Archicebus was a tree dweller and probably lived on insects. Scientists have not yet determined that it is a direct human ancestor. It may have been an offshoot of the group of animals that eventually gave rise to monkeys and humans.
The researchers suggest that Archicebus could have been on the “tarsiiforme” branch of the primate evolutionary tree that ended up not at monkeys and humans but at tarsiers, a species of small, big-eyed mammals that live in present-day Asia. Our branch, which we share with apes and monkeys, was the “anthropoids.” But the researchers hope to reach a firm conclusion following further analysis.
A team of researchers at the Carnegie Museum of Natural History in Pittsburgh, Pennsylvania has been studying the fossil for the past decade and identifies a key divergence in the primate evolution timeline at around the time of Archicebus. In other words, it’s not just its age and completeness that makes this skeleton so unique. The research team believes that this ancient creature—extremely tiny and weighing less than an once—is the milestone between tarsiers (A small tree-dwelling primate with large eyes and long tail) and anthropoids (monkeys and apes that include gorillas, chimpanzees, and orangutans).
Chris Beard, one of the Carnegie researchers, is convinced that humanity’s earliest primate ancestors lived in Asia and began their evolution toward human form there. They would have finally moved to Africa around 35 million years ago and completed the metamorphosis there.
Archicebus seems to be a prime contender for “missing link” status, in that it exhibits features that are common to both tarsiiformes and anthropoids. Its body shape resembles that of the tarsiers, but it had the anthropoid traits of fingernails and toenails, a rounded face and brain case, a short snout, and front-facing eyes. Also, its unusually shaped heel bones closely resemble those of certain species of monkeys living today, such as the marmosets.
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