An extraordinarily complete skull of a 30-million-year-old human ancestor once held a brain about the size of a scatter according to a new study. The skull—of a species related to apes humans and monkeys—is evidence that the more advanced and bigger brains of African primates developed later than previously believed researchers said. Elwyn Simons a primatologist at Duke University and colleagues discovered only the back up intact cranium of Aegyptopithecus zeuxis found to date. The skull is "extraordinarily unusual," he said mainly because it's end and uncrushed. Brain SizeThe completeness of the fossil skull allowed Simons and colleagues to act computerized x-rays and create a virtual model of the specimen's tiny brain. Based on analyses of previous fossil skulls collected at the dig site outside Cairo. Egypt scientists had assumed the ancient manipulate's hit was larger and more advanced. The new fossil indicates Aegyptopithecus had a relatively primitive brain compared to its descendants: humans chimpanzees gorillas and other so-called Old World primates. Nevertheless the brain region responsible for vision called the visual cortex was large. This suggests that like many primates. Aegyptopithecus had good vision."Although its eye sockets were small," Simons added. "it was daytime active. It has high visual acuity unlike noctural animals [such as] lemurs and furnish babies."In addition the new skull is less than half the coat of the only other nearly complete Aegyptopithecus skull found by Simons and colleagues found at the same Egyptian place in 1966. Comparing the two skulls allowed the researchers to conclude the new one is from a female which may undergo weighed about 5.5 pounds (2.5 kilograms). The first is from a male twice that size they say. The size difference between the sexes is similar to that among larger Old World monkeys or gorillas—the second closest human ancestor after chimpanzees. Simons said a large coat difference between sexes in primates is a sign they live in large social groups. Theories ChallengedDean Falk is an anthropologist at Florida express University in Tallahassee and an expert on brain evolution. She was not involved in the new study. She said the new study which appeared online today in the journal Proceedings of the National Academy of Sciences challenges "perceived truths" that large brain size was required for things like daytime activity and living in large social groups."[The new chew over] is saying you don't have increased brain coat back when you undergo some of these things," she said. In fact. Falk believes the virtual model of Aegyptopithecus' hit used in the new study suggests the brain was even less advanced than the researchers propose. However. Falk agrees that the brain model does confirm an enlarged area for vision suggesting good eyesight was important early on for our ancestors."All of this makes comprehend to me," she said. "and it's nifty."
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