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Plesiadapiformes ("Adapid-like" or "near Adapiformes") is an extinct (and possibly paraphyletic or polyphyletic ) order of mammals. It is either closely related to the primates or a precursor to them. Many are too derived to be ancestral to primates, but the earliest Plesiadapiformes have teeth that are strongly indicative of a common ancestor. ''Purgatorius'' is believed to be close to the last common ancestor of primates and Plesiadapiformes. Plesiadapiformes first appear in the fossil record between 65 and 55 million years ago,〔(Paleontologists discover most primitive primate skeleton - PhysOrg.com )〕 though many were extinct by the beginning of the Eocene. It is possible that they are the first mammals to have developed finger nails in place of claws. }} }} }} One possible classification table of plesiadapiform families is listed below. *ORDER PLESIADAPIFORMES * * Family Micromomyidae * * Superfamily Paromomyoidea * * * Family Paromomyidae * * * Family Picromomyidae * * * Family Palaechthonidae * * * Family Picrodontidae * * * Family Microsyopidae * * Superfamily Plesiadapoidea * * * Family Chronolestidae * * * Family Plesiadapidae * * Superfamily Carpolestoidea * * * Family Carpolestidae ==References== 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「Plesiadapiformes」の詳細全文を読む スポンサード リンク
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