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2013-06-05 13:58:15 UTC
Grenoble, 5 June 2013: An international team of researchers has announced the discovery of the world's oldest known fossil primate skeleton representing a previously unknown genus and species named Archicebus achilles. The fossil was unearthed from an ancient lake bed in central China's Hubei Province, near the course of the modern Yangtze River. In addition to being the oldest known example of an early primate skeleton, the new fossil is crucial in elucidating a pivotal event in primate and human evolution—the evolutionary divergence that led to modern monkeys, apes and humans (collectively known as anthropoids) on one branch, and to living tarsiers on the other. The scientific paper describing the discovery is published today in the prestigious journal Nature.
The fossil was recovered from sedimentary rock strata that were deposited in an ancient lake roughly 55 million years ago, during the early part of the Eocene Epoch. This was an interval of global "greenhouse" conditions, when much of the world was shrouded in tropical rainforests and palm trees grew as far north as Alaska. Like most other fossils recovered from ancient lake strata, the skeleton of Archicebus was found by splitting apart the thin layers of rock containing the fossil. As a result, the skeleton of Archicebus is now preserved in two complementary pieces called a "part" and a "counterpart," each of which contain elements of the actual skeleton as well as impressions of bones from the other side
http://www.sciencecodex.com/discovery_of_oldest_primate_skeleton_ancestor_of_humans_and_apes-113506