ザンビアのブロークンヒルの頭蓋骨の年代と,人間の進化におけるその位置
Rainer Grün1,2, Alistair Pike3, Frank McDermott4
1Australian Research Centre for Human Evolution, Griffith University, Nathan, Queensland, Australia. Rainer.Grun@griffith.edu.au.
Nature
|April 17, 2020
まとめ
ブローケンヒルの頭蓋骨は かつては50万年前のものと考えられていましたが 今は29万9千年前のものと考えられています この発見は 中世プレイストセンのアフリカで共存した 多数のヒトの系統を明らかにし 人類の進化の理解に影響を与えました
科学分野:
- 古人類学
- 人間 の 進化 論
- アフリカの古生物学
背景:
- 1921年にザンビアで発見された重要なホミニン化石である ブロークンヒル (Kabwe) の頭蓋骨.
- 以前はホモ・ロデシアンシスまたはホモ・ハイデルベルクンシスと分類されていたが,その年代と進化の位置は,非体系的な回復と正確な年代測定の欠如のために不確実であった.
研究 の 目的:
- 直接分析を使って 骨格の正確な年代を決める
- 中期プレイストセンのアフリカにおける ホミニン集団の進化的文脈を再評価する.
主な方法:
- ブロークンヒルの頭蓋骨の直接分析
- 放射線年代測定法で正確な年齢を推定する
主要な成果:
- ブロークンヒル頭蓋骨の年齢は299年±25000年 (平均±2σ) と見積もられている.
- この年齢は,ホモ・サピエンス,ホモ・ハイデルベルゲンシス/ホモ・ロデシエンシス,そしてホモ・ナレディを含む複数のホミニン系が,後期プレイストセーン時代にアフリカで共存していたことを示している.
結論:
- アフリカにおけるホモ・サピエンスの一つの祖先の系統に関する以前の仮定に 挑戦しています
- ユーラシアに匹敵する 中期プレイストセンのアフリカにおける ホミニン多様性のより複雑な描写を示唆しています
- ホモ・サイピエンスの進化におけるホモ・ハイデルベルゲンシス/ホモ・ロデシエンシスの直接的な祖先の役割について疑問を投げかけている.
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