( CNN ) -- The oldest-known hominid skeleton was a 4-foot-tall female who walked upright more than 4 million years ago and offers new clues to how humans may have evolved , scientists say . This sketch shows what a 4 million-year-old hominid , nicknamed Ardi , may have looked like . Scientists believe that the fossilized remains , which were discovered in 1994 in Ethiopia and studied for years by an international team of researchers , support beliefs that humans and chimpanzees evolved separately from a common ancestor . `` This is not an ordinary fossil . It 's not a chimp . It 's not a human . It shows us what we used to be , '' said project co-director Tim White , a paleontologist at the University of California , Berkeley . Ardipithecus ramidus , nicknamed `` Ardi , '' is a hominid species that lived 4.4 million years ago in what is now Aramis , Ethiopia . That makes Ardi more than a million years older than the celebrated Lucy , the partial ape-human skeleton found in Africa in 1974 . Ardi 's 125-piece skeleton includes the skull , teeth , pelvis , hands and feet bones . Scientists say the data collected from Ardi 's bone fragments over the past 17 years push back the story of human evolution further than previously believed . `` In fact , what Ardipithecus tells us is that we as humans have been evolving to what we are today for at least 6 million years , '' C. Owen Lovejoy , an evolutionary biologist at Kent State University and project anatomist , said Thursday . Analysis of Ardi 's skeleton reveals that she weighed about 110 pounds , had very long arms and fingers , and possessed an opposable big toe that would have helped her grasp branches while moving through trees . Ardi 's brain was believed to be the size of a chimp 's , but she also had many human-like features , such as the ability to walk upright on two legs . Her `` all-purpose type '' teeth indicate that she probably ate a combination of plants , fruits and small mammals , scientists say . `` The anatomy behind this behavioral combination is very unexpected and is certain to cause considerable rethinking of not only our evolutionary past , but also that of our living relatives : the great apes , '' said Alan Walker , professor of biological anthropology at Pennsylvania State University . Many scientists hypothesize that humans took a different evolutionary trajectory from those of chimpanzees , bonobos and gorillas . Ardi 's findings help challenge earlier beliefs that humans evolved from chimpanzees , their closest genetic relatives , scientists say . Researchers are still trying to pinpoint when the two lineages -- chimps and humans -- split from their common ancestor . Digging up the past has not been easy . Scientists stumbled upon the Ardipithecus fossil in 1994 when a graduate student found a single upper molar tooth . The rest of Ardi 's fossilized bones , sandwiched between layers of volcanic rock , took three years to be recovered and many more to be analyzed . `` In many ways , the discovery of Ardipithecus has been like a marathon , '' White said . `` Ardipithecus ramidus and its prevailing anatomy revolutionize the way most of us understood the earlier part of our evolutionary history , '' said team member Yohannes Haile-Selassie , paleontologist at the Cleveland Museum of Natural History . The Ardi findings are the work of 47 paleontologists and geologists representing 10 countries . The results will be published Friday in 11 articles in a special edition of the journal Science . Until now , Australopithecus , nicknamed `` Lucy , '' was the oldest fossil studied by scientists seeking to explain human evolution . Lucy is believed to have lived about 3.2 million years ago in what is now Ethiopia . Many scientists credit Ethiopia with taking the lead in helping the world better understand the origins of humans . `` This finding points to a deeper sense of our [ humans ' ] interconnectedness , '' Samuel Assefa , Ethiopian ambassador to the United States , said Thursday . `` We are all Ethiopians at heart . '' Ardi 's skeleton resides in the National Museum of Ethiopia in Addis Ababa .
Researchers have unveiled a 4.4 million-year-old skeleton of a hominid female . The fossil , nicknamed Ardi , may be the oldest hominid skeleton ever found . It replaces Lucy , a much-publicized skeleton that dates back about 3 million years . Scientists : Ardi suggests humans and chimps evolved from a common ancestor .