ティラノサウリドの骨格のデザインは,最初に小さな体サイズで進化した
Paul C Sereno1, Lin Tan, Stephen L Brusatte
1Department of Organismal Biology and Anatomy, University of Chicago, Chicago, IL 60637, USA. dinosaur@uchicago.edu
Science (New York, N.Y.)
|September 19, 2009
まとめ
初期のティラノサウロイドは,初期の白亜紀の小さな恐竜で,すでに後の巨大ティラノサウロイドの重要な特徴を有していた. これらの特徴は,メソゾーイク時代を通して頂点の捕食者の出現を可能にしました.
科学分野:
- パレオントロジー・パレオントロジー
- 脊椎動物学 脊椎動物学
- メソゾイク時代の生態系
背景:
- クレタ紀後半の北の大陸は,大きな体型のタイラノサウルスの恐竜 (>2.5トン) が支配していた.
- これらの頂点捕食者は,大きな頭蓋骨,特殊な歯,強力な筋,特定の四肢の比率を含む明確な機能的な専門性を展示しました.
研究 の 目的:
- ティラノサウルスの専門性の進化的起源を調査する.
- ティラノサウロイド系におけるこれらの特徴の最も初期の発生を特定する.
主な方法:
- 古生物学的な発掘と化石の分析.
- 骨格の特徴の比較解剖学的研究.
- 捕食者の適応の機能的形態学の解釈.
主要な成果:
- 中国北東部の低白亜紀の新型,小型の基礎型ティラノサウロイドの発見.
- この初期の種における重要なティラノサウリドの特異性 (大きな頭蓋骨,切歯状の歯,強い筋,カーソリアルな後肢) の特定.
- これらの特徴は,後のティラノサウリドで観察された体のサイズの大幅な増加の前に存在していました.
結論:
- 大型のティラノサウリドの機能的特異性は,小型の祖先にもあった.
- これらの既存の適応は,メソゾーイク期におけるティラノサウリドの後の進化的放射とマクロプレダターとしての支配を容易にした.
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