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'''Ardipithecus''' is a very early hominin genus (subfamily Homininae). Because it shares several traits with the African great apes (genus ''Pan'' and genus ''Gorilla''), it is considered by some to be on the chimpanzee rather than human branch, but most consider it a proto-human because of a likeness in teeth with ''Australopithecus''. ''A. ramidus'' lived about 4.4 million years ago during the early Pliocene.
Two species have been described, '''Ardipithecus ramidus''' and '''Ardipithecus kadabba'''. The latter was initially described as a subspecies of ''A. ramidus'', but on the basis of teeth recently discovered in Ethiopia has been raised to species rank. ''A. kadabba'' is dated to have lived between 5.8 million to 5.2 million years ago. The canine teeth show primitive features that distinguish them from those of more recent hominines. ''A. kadabba'' is believed to be the earliest organism yet identified that lies in the human line following its split from the lineage that gave rise to the two modern chimpanzee species. Remains from both species have been found in the Middle Awash.
On the basis of bone sizes, ''Ardipithecus'' species are believed to have been about the size of a modern chimpanzee. The toe structure of ''A. ramidus'' suggests that the creature walked upright, and this poses problems for current theories of the origins of hominid bipedalism: ''Ardipithecus'' is believed to have lived in shady forests rather than on the savannah, where the more energy efficient locomotion permitted by bipedalism would have been an advantage. New thought will be necessary in order to reconcile the savannah theories with the current knowledge of early forest-dwelling hominids.

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External links

External links

★ BBC News: Amazing hominid haul in Ethiopia

★ NY Times: Two Splits Between Human and Chimp Lines Suggested

★ Minnesota State University

★ Archaeology info