In Science this week is a stunning array of articles describing the latest information on the 4.4 million year old hominid Ardipithecus ramidus, a hominid which is considered ancestral to humans.
Probable life appearance in anterior view of Ardipithecus ramidus ("Ardi"), ARA-VP 6/500.
Illustration © 2009, J.H. Matternes
The intensive research has revealed a need for the revision of what paleontologists have long considered about our immediate ancestors. Genetically, evidence is unequivocal that our nearest living relative is the chimpanzee, and paleontologists believed that our joint ancestor, estimated to have lived some 6 million years ago or more, would have both chimpanzee and human traits. But what Ardipithecus suggests is that many of the chimpanzee traits may have evolved after our two species lines diverged.
The 11 articles written by a group of nearly 50 researchers, include a detailed analysis of Ardi, a substantially complete A. ramidus, recovered from the Middle Awash region of the Rift Valley. Ardi was a female who weighed about 50 kilograms and stood about 120 centimeters tall; she is the tall drink of water whose reconstruction is illustrated in this blog post. Also featured are data from over 110 Ardipithecus remains from the Afar Rift of northeastern Ethiopia. In addition to a detailed examination of the differences between Ardipithecus, Australopithecus and her more remote descendants, the articles include summaries of what the researchers believe the environment for Ardipithecus ramidus was, as well as what her diet and living style might have been.
A set of images was provided to us science journalists types, so I (naturally) created a photo essay of the story.
- Ardipithecus Ramidus - An Ancient Human Ancestor Surprise, a photo essay
- Lucy, famous Australopithecus afarensis
- Bipedal locomotion
- Middle Awash
By the way, I'm told the Discovery Channel will air a documentary about this research on October 11, 2009; should be interesting!
- New York Times: Fossil Skeleton From Africa Predates Lucy
- Cleveland Plain Dealer: Cleveland researchers say fossil find overturns thinking on human evolution
- Wall Street Journal: Fossils Shed New Light on Human Past
- National Geographic: Ardi's Secret: Did Early Humans Start Walking for Sex?
- Los Angeles Times: Fossils radically alter ideas about the look of man's earliest ancestors