恐竜の関係と初期の恐竜の進化に関する新しい仮説
Matthew G Baron1,2, David B Norman1, Paul M Barrett2
1Department of Earth Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EQ, UK.
Nature
|March 24, 2017
まとめ
新しい恐竜の系統樹は,オルニチシアとセロポダが密接に関連し,オルニソセリダ群を形成することを示唆しています. これは初期の恐竜の進化に関する 長い間持っていた見解に異議を唱え 主要な恐竜群を再分類する必要があります
科学分野:
- 古生物学
- 進化生物学
- 体系的な研究
背景:
- 恐竜は歴史的に2つの主要クラードに分類されている. オーニチシアとサウリシア.
- この伝統的分類は130年間 合意されてきたものです
- 現在のクラディスティック定義は,初期の恐竜の進化を理解する上で課題を提示しています.
研究 の 目的:
- 主要な恐竜群の遺伝関係に関する新しい仮説を提案する.
- 恐竜の進化に関する 既存のコンセンサスに 挑戦するためです
- 現在のクラディスティック定義の問題点に対処する.
主な方法:
- 主要な恐竜群の遺伝分析
- 新しい進化樹トポロジーの開発
- 恐竜群のクラディスティック再定義と診断
主要な成果:
- OrnithischiaとTheropodaの姉妹グループ関係が発見され,Ornithoscelidaという新しいクラードを形成した.
- サウロポドモルファ (Sauropodomorpha) とヘレラサウリダ (Herrasauridae) は,オルニソセリダ (Ornithoscelida) のモノフィレティック・アウトグループを形成する.
- この新しいトポロジーは,初期の恐竜のクラドゲネシスと性格の進化の再評価を必要とします.
結論:
- 提案されたオルニソセリダ群は,伝統的な恐竜分類に異議を唱える.
- ヘレラサウリドとセロポッドで独立して超肉食性の獲得が提案されています.
- この新種の遺伝学は,前述のセロポッドと初期のオルニシキア間の解剖学的収束について説明しています.
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