恐竜の進化的放射における優越性,競争,そして機会主義
Stephen L Brusatte1, Michael J Benton, Marcello Ruta
1Department of Earth Sciences, University of Bristol, Bristol BS8 1RJ, UK. brusatte@uchicago.edu
まとめ
恐竜はトライアス紀後期に,優位性ではなく,歴史的出来事によって上昇した. 彼らの進化速度と多様性は,競合する動物と類似しており,これは偶然が重要な役割を果たしたことを示唆している.
科学分野:
- パレオントロジー・パレオントロジー
- 進化生物学の進化生物学について
- メソゾイク時代の生態系
背景:
- トライアス紀後期 (2億3千万~2億年前に) は恐竜の多様化が見られた.
- 恐竜の興起は,しばしば他のアーコサウルスの競争的代替に起因する.
- クロロターサンのアーコサウルスは,初期の恐竜の支配的な競争相手でした.
研究 の 目的:
- 基礎恐竜とクロロターサンのアーコサウルスの間の進化速度と形態学的差異を比較する.
- トライアス紀におけるアーコサウルスの多様化を促した要因を調査する.
- 恐竜の興起における競争的代替の仮説を検証するために.
主な方法:
- 進化の速度の比較分析 進化の速度の比較分析 進化の速度の比較分析
- 恐竜とクルーロターサンの系統における形態学的差異の評価.
- トライアス紀のアーコサウルスの放射線における進化的傾向の検討.
主要な成果:
- 恐竜は,クロターサンスと比較して,より低い形態学的差異を示した.
- 基礎恐竜の進化の速度は,競合する恐竜と区別がつかないものでした.
- トリアス紀のアーコサウルスの放射は,進化の速度が低下し,格差が増大することを示した.
結論:
- 恐竜の出現は,固有の優位性ではなく,歴史的偶然によって引き起こされた可能性が高い.
- 性格の進化と体型の多様性の分離は,アーコサウルスの放射線を特徴づけた.
- 競争だけでは,恐竜の進化的放射線を完全に説明することはできません.
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