HiddenMysteries: Perfect 29 mln-year-old fossilised skull unearthed in Egypt

The second and almost perfect 29 million-year-old fossilised skull of an ancient relative of humans, apes and monkeys has been unearthed in Egypt, media reported Tuesday.

The skull, from a species known as Aegyptopithecus zeuxis -- "linking Egyptian ape" or dawn ape, was identified by Duke University primatologist Elwyn Simons in a quarry on the outskirts of Cairo. Because of the new specimen's remarkable wholeness, Simons and his colleagues were able to subject it to micro CT scanning, a computerized X-ray technique that can be used to calculate the approximate dimensions of the brain the cranium once encased.

According to Simons, the specimen is from a young female that lived in the early Oligocene, a period of global cooling, volcanic eruptions and seismic disturbance, driven by the collision of the Indian and Asian continental plates.

Based on previous fossils collected at the same dig site in a quarry outside Cairo, scientists have hypothesized that this early monkey already would have had a relatively large brain, said Simons.

But the researchers' new report, which displays the computer-reconstructed brain as a false-color red mass within the grey skull case, suggests that the skull was half the size of the first dawn ape skull, a male found in 1966, suggesting modern apes and monkeys developed larger brains later in evolution.

The species "had a brain that might have been even smaller than that of a modern lemur's," Simons said. "This means the big-brained monkeys and apes developed their large brains at a later point in time."

But measurements led the scientists to believe it was capable of forming large social troops similar to those seen in modern day primates. The shape of the eye sockets suggest the species was active during the daytime, like modern apes.

Aegyptopithecus fossils have been found in two quarries separated by about a kilometer within Egypt's Fayum Depression. Scientific evidence suggests the location, now arid, was a tropical forest 29 million years ago.

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Perfect 29 mln-year-old fossilised skull unearthed in Egypt

Tuesday, May 15 2007 @ 08:13 AM CDT