Ardipithecus
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†Ardipithecus kadabba |
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.
[edit] External links
- BBC News: Amazing hominid haul in Ethiopia
- NY Times: Two Splits Between Human and Chimp Lines Suggested
- Minnesota State University
- Archaeology info
Sahelanthropus tchadensis • Orrorin tugenensis • Ardipithecus
Australopithecus: A. anamensis • A. afarensis • A. bahrelghazali • A. africanus • A. garhi
Paranthropus: P. aethiopicus • P. boisei • P. robustus
Homo: H. habilis • H. rudolfensis • H. georgicus • H. ergaster • H. erectus (H. e. lantianensis • H. e. palaeojavanicus • H. e. pekinensis • H. e. soloensis) • H. cepranensis • H. antecessor • H. heidelbergensis • H. neanderthalensis • H. rhodesiensis • H. floresiensis • Homo sapiens (H. s. idaltu • H. s. sapiens)
