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Tuesday, September 13, 2011

Human Ancestors from South Africa

Lee Berger and the Cranium of Australopithecus sediba MH1. (Picture from: http://he.wikimedia.org/)
Matthew, 9-year-old boy, accidentally discovered a fossil that could change the view of human ancestry. "Dad, I found a fossil," said Matthew told his father. 
Australopithecus sediba site. (Picture from: http://www.macroevolution.net/)
Lee Berger, a paleo-anthropology. Berger saw the stone that held the 9-year-old boy and instantly realized how important the findings.

A diagram of how the skeletons of Australopithecus sediba came to be preserved in the Malapa cave deposit. From Dirks et al, 2010. (Picture from: http://scienceblogs.com/)
The fossils were discovered in August 2008 turned out to be the neck bones of ancient hominins. When Berger turned the stone, seen protruding lower jaw bone. "I can not believe it," he said.

From that site, paleo-anthropologist at the University of the Witwatersrand, Johannesburg, South Africa, found the fossil skeleton of a boy and a young woman of 20 years.

The skeletons of Australopithecus sediba. The more complete skeleton of the adolescent male (MH1) is on the left, and the less complete adult (MH2) is on the right. From Berger et al, 2010. (Picture from: http://scienceblogs.com/)
Berger claims that the specimen was dubbed Karabo, along with a number of other fossils found since 2008 in Malapa Cave, northwest of Johannesburg, is a new species named Australopithecus sediba. In the language of Sesotho, sediba means well.

Scientists who examined the fossils Karabo said although primitive appearance, Karabo has many characteristics of the genus Homo, the genus where modern humans (Homo sapiens) shelter.

"This research will change the way we look at evolution," Berger said last week. "We have been arranging all the pieces together. Karabo now give a more complete picture to be investigated."

The discovery of the fossil back into the spotlight after the publication of five scientific papers in the journal Science last week. This new theory, based on results of examination of the legs, pelvis, hands, and brains of the two fossils, it tends to underestimate the status of Homo habilis, which is often regarded as the man who first used the tool, as a link between Australopithecines and Homo family, Homo habilis originated of the 200-300 thousand years younger than the A. sediba, but some other characteristics are even more primitive.

Studied bone Berger and his team, which consists of more than 80 researchers, believed to be transitional fossils, with a mix of species that are more ancient features and more advanced. But modern characteristics, traits that resemble human beings, which makes it special.

Both fossil Karabo that underlie the new theory was thought to have died at the same time. Landslides buried in sediments, two fossils were almost perfectly preserved deep in the cave. Karabo lived about one million years after the fossil Lucy, found in East Africa. Sediba true lineage is still a speculation. Some researchers believe that the species of Lucy (Australopithecus afarensis) play a role in the birth Australopithecine South Africa, including the species Australopithecus africanus.

Now researchers suspect that A. africanus, or even an older species, is the ancestral species Karabo. "The evidence is based on primitive and modern features on the foot and ankle A. sediba, show that traits are not inherited from Lucy's species, but from an ancient hominin lineage that has not been identified," said Berger. "A hand bones that have been advanced sediba showed he was not the ancestor of H. habilis, whose hands were more primitive."

Tim Berger argues that the fossil was a mixture of primitive features Australopithecine and characteristics of modern humans are more advanced. They claim there is a possibility of this new species is the best candidate for the ancestor of our genus, Homo.
Timeline of Fossils. (Picture from: http://www.lloydpye.com/)
Allegations were supported by the results of dating techniques and paleo-magnetic uranium conducted Robyn Pickering from Melbourne University. Measurement set-old fossil was 1977 million years old. The results of these measurements to change the appearance of specific traits became even earlier Homo. During this characteristically modern human fossils recently discovered from 1.9 million years ago, Homo habilis and Homo rudolfensis, regarded as the ancestor of Homo erectus.

In a paper also presented a well-developed cerebellum, and the shape of the foot and ankle are unique, a combination of ape and human features in one package anatomy.

"Those two things make it a candidate ancestor of the genus Homo is better than the prior art, such as Homo habilis," says Berger. "Karabo, there may be a direct ancestor of Homo erectus, a human ancestor of today." *** [TJANDRA DEWI | DAILYMAIL | AP | GRAPHIC NEWS | KORAN TEMPO 3645]
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