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The earliest hominid identified so far, A. ramidus was discovered in Aramis, Ethiopia in 1994 by Tim White, Gen Suwa and Berhane Asfaw. Its name literally meaning "ground man-root", this species is approximately 4.5 million years old. At first thought to be part of the Australopithecine family, differences were identified that set it apart from later members of the family.

Seventeen specimens were recovered from the site in Ethiopia. Included were miscellaneous teeth, a manible from a juvenille, a cranial fragment and three bones from a left arm of one individual. It is difficult to determine whether or not this species was bipedal, since there were no femurs or hip bones recovered. If it was, such a discovery would push bipedalism back over a million years further than was thought less than 10 years ago.

The dental features of Ardipithecus ramidus are more apelike than that of A. afarensis, with narrower molars and thin enamel. The arm suggests some apelike features, but it is evolved to a degree such that the type of locomotion is difficult to figure out. After the initial publication of the findings after the dig in Ethiopia, White et al. changed the genus classification from Australopithecus due to variations in partial skeletons recovered late in their excavation. Preliminary analysis shows that the skeleton exhibits a more primitive, chimplike makeup.

Even though A. ramidus is similar to later members of the Australopithecus genus, the likelihood of it being a direct ancestor to the human being is slim. More likely, both later Australopithecines and A. ramidus had a common ancestor and the Australopithecine line progressed into the modern human.

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