Author: Bruce Bower / Source: Science News
Fossils unearthed from an Ethiopian site not far from where the famous hominid Ardi’s partial skeleton was found suggest that her species was evolving different ways of walking upright more than 4 million years ago.
Scientists have established that Ardi herself could walk upright (SN Online: 4/2/18). But the new fossils demonstrate that other members of Ardipithecus ramidus developed a slightly more efficient upright gait than Ardi’s, paleoanthropologist Scott Simpson and colleagues report in the April Journal of Human Evolution. The fossils, excavated in Ethiopia’s Gona Project area, are the first from the hominid species since 110 Ar. ramidus fossils, including Ardi’s remains, were found about 100 kilometers to the south (SN: 10/24/09, p. 9).
Gona field surveys and excavations from 1999 through 2013 yielded Ar. ramidus remains, including 42 lower-body fossils, two jaw fragments and a large number of isolated teeth. Several leg and foot bones, along with a pelvic fragment, a lower back bone and possibly some rib fragments, came from the same individual. The same sediment layers, characterized by previously dated reversals of Earth’s magnetic field, contained fossils of extinct pigs, monkeys and other animals known to have lived more than 4 million years ago.
Unlike Ardi, the fossil individual at Gona walked on an ankle that better supported its legs and trunk, says…
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