Ardipithecus ramidusの頭蓋骨と,ヒト類の起源に対するその影響
Gen Suwa1, Berhane Asfaw, Reiko T Kono
1University Museum, University of Tokyo, Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan. suwa@um.u-tokyo.ac.jp
Science (New York, N.Y.)
|October 8, 2009
まとめ
Ardipithecus ramidusの頭蓋骨は,現代の類人猿と後のオストラロピテコスから大きく異なる,ユニークなプレ・オストラロピテコスホミニドの頭蓋骨の特徴を明らかにしています. この発見は,初期のヒト類の進化に関する我々の理解を再構築する.
科学分野:
- 古人類学は,古人類学である.
- 人間の進化 人類の進化
- 霊長類の解剖学について
背景:
- 現代の人類に至る進化の系統は複雑で,初期のヒト類は原始的および派生的な特徴のモザイクを示しています.
- 初期のホミニドの頭蓋骨顔の形態を理解することは,彼らの系統遺伝的関係を再構築するために非常に重要です.
研究 の 目的:
- Ardipithecus ramidusの頭蓋骨 (ARA-VP-6/500) の顔形態と構造を分析するために.
- Ardipithecus ramidusを,現存する類人猿 (Pan troglodytes, P. paniscus) とオーストラリア類人猿 (Australopithecus) と比較するために.
- ミオ・プレオセンのホミニドの頭蓋骨の特徴を解明する.
主な方法:
- Ardipithecus ramidusの頭蓋骨と他のヒト類や類人猿の遺骸の解剖学的比較.
- マイクロコンピュータトモグラフィー (マイクロCT) による頭蓋骨・顔面構造の分析.
主要な成果:
- Ardipithecus ramidusの頭蓋骨は,小さな内頭蓋骨容量 (300~350cc) と相対的な頭蓋骨サイズを示しています.
- 特徴的な特徴には,中面の投影と,極端な下面面のプログナシズムがないことが含まれます.
- 頭蓋骨の底部とジゴマキシラー骨格は,パン種とアウストラロピテクスと異なる.
結論:
- Ardipithecus ramidusは,現代のアフリカ類人猿やオーストラリア類人猿とは異なる独特の頭蓋骨顔面形態を持っています.
- Sahelanthropusと共通する特徴は,ミオ・プリオセンのヒト類の独特の頭蓋骨形態を示唆する.
- この研究は,現存する類人猿と比較して,初期のホミニドの重要な頭蓋骨顔面の違いを強調しています.
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