Yonex Nano Speed 9900 Canada

Lucy walked upright.

aus scinexx

"Lucy” lief auf modernen Füßen

3,2 Millionen Year-old metatarsals been definitively bipedalism of Australopithecus

Australopithecus-wife "Lucy" and her contemporaries were already as upright as we do. The decisive proof that this is now a 3.2 million year old metatarsal bone. The bones discovered in Ethiopia show that these pre-humans already possessed a modern shaped foot with arch support - a prerequisite for true bipedalism. The now in Science Fund described automatically ended a years-long research dispute.

When our ancestors began walking upright? Ran "Lucy", the famous representative of the Australopithecus afarensis, 3.2 million years ago on two legs like us? This issue is controversial for years. While some paleontologists assume that this Vormenschenart walking upright already well controlled, others believe that Lucy and Co were at best semi-erect to go - as a transitional form between the four-legged ape gear and true bipedalism.

midfoot arch decisive indication Zweibeinigkei t

a decisive indication on this issue is the shape of the foot: If the middle of the australopithecines similar to that of us humans have had a real two-axis vault, would be an indication of an advanced adaptation to bipedalism. The modern human foot arch consists of a metatarsal bone formed by the longitudinal and transverse arch. supported by muscles, they serve the two-legged walking two functions: they increase the leverage when pushing off the foot and improve the shock absorption at the restart. Shown is the arching including the metatarsal bones.

first metatarsal bones of an Australopithecus discovered

precisely this current lack of fossil evidence of an international team of researchers has now been discovered in Ethiopia: a 3.2 million years old fourth metatarsal bones of Australopithecus afarensis. The bone was found in the so-called Hadar locality 333, one of the richest deposits of Australopithecus afarensis fossils in East Africa.

"This fourth metatarsal bone is the only one who is far from Australopithecus afarensis known and a key document for the early evolution of the uniquely human way of walking," says William Kimbel of Arizona State University. Because the bone has several characteristics that are similar to that of a modern foot. Thus the two ends of the bones are twisted against each other and there are indications that the metatarsal relatively steep from the ankle to the toes fell off.

Significant differences to Ardipithecus

This Features indicate not only an already modern pace, they also differ significantly from the ankle bones of about one million years earlier pre-human living Ardipithecus ramidus. This could probably also run already raised short-term, but his feet kept many features of the tree-dwelling primate ancestors: They had no vaults, were more flexible than the relatively rigid human feet and had a very large moving toes. Lucy and her contemporaries, however, were clearly no more to climb, for the better adapted to walking upright.

"The realization that the duckfoot bends very early in our evolution appeared shows that the unique structure of our fundamental human foot for locomotion, "Carol Ward, lead author of the study explained by the University of Missouri. "If we understand how natural selection shaped the human skeleton, we also gain insights into the workings of today's skeleton. The arches of our feet were our ancestors as important as now for us "(Science, 2011 DOI: 10.1126/science.1201463).

(Arizona State University Science, 11/02/2011 - NPO)