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''Chororapithecus'' is an extinct ape genus that lived about during the Miocene and is represented by one species, ''Chororapithecus abyssinicus''. It is believed to be the earliest known species of gorilla. Its existence indicates that the last common ancestor between the human/chimpanzee lineage and gorillas may have lived greater than , which is at least 2 million years earlier than the previously thought date of divergence of about 8 million years ago. The only evidence found of this extinct ape is currently nine Fossilized teeth of at least three individuals, recovered from the Chorora Formation which runs along the southern Afar Depression of Ethiopia (the same place where the remains of Lucy were discovered in 1974). Analysis of eight molars (two of them fragmented) and a canine tooth show that their structure is partly similar to modern gorillas. 〔 The researchers compared the make-up of the teeth to those of other current and fossil apes, and concluded that the new ape fossils were possibly those of a species of gorilla which ate mostly high-fiber plants, and that the fossil species is likely a 'direct ancestor' of the gorillas currently living in Africa. Alternatively, the idea that the finds are the remains of early hominins has not been ruled out entirely.〔 ==Previous research== Previous efforts to find fossils of great ape ancestors in Africa from between 12 and 8 million years ago had been largely unsuccessful. This absence led some to hypothesize that apes were absent from Africa during this time, and had recolonized Africa from areas in Asia where fossils from this time period are more plentiful. Molecular estimates that humans and gorillas diverged after 8 million years ago were consistent with this idea, in which an adaptive radiation might have occurred after a single species entered Africa and began to adapt to different environments. Current fossils and research prior to this finding indicate that the evolutionary split between gorillas and humans occurred around 8 million years ago. The new fossils indicate that the split may have happened as long as 10.5 million years ago. It is thought that humans shared a common ancestor with chimpanzees as recently as . 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Chororapithecus」の詳細全文を読む スポンサード リンク
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