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イチヨルニスの完全な頭蓋骨は,鳥の頭部をモザイクで照らしています

Daniel J Field^1,2, Michael Hanson¹, David Burnham³

¹Department of Geology & Geophysics and Peabody Museum of Natural History, Yale University, New Haven, CT, USA.

|May 4, 2018

まとめ

新しい化石は,古代の鳥イッチオルニス・ディスパールが現代の鳥と似た移行性鼻と運動性頭蓋骨を持っていたことを明らかにし,これは鳥の栄養システムの初期の進化を示している. この鳥には恐竜のの筋肉も残っていて祖先と現代の特徴が混在しています

科学分野:

古生物学
進化生物学
比較解剖学

背景:

生きている鳥の頭蓋骨は恐竜の祖先と比べると大きく変化し歯のない尻尾と複雑な運動システムを備えています
これらの鳥類の頭蓋骨の特徴の進化の順序と初期の発達は,大部分は特徴づけられていない.
イチョーニス・ディスパル (イチョーニス・ディスパル) は紀元後期に生息していた歯のある鳥で遺伝学的に重要な位置を占めており祖先の特徴を保ちながら現代の鳥の放射能に接近している.

研究の目的:

イチヨルニスの頭蓋骨の形状と進化の変異を調査する
イチヨルニスの頭蓋骨を再構築する
鳥の食器,脳,そしての筋肉の初期進化を理解する.

主な方法:

イチョーニス・ディスパールの3次元保存された4つの新種を分析した.
高解像度コンピュータトモグラフィー (CT) スキャニングにより,イッチオルニスの不均一な頭蓋骨の3D再現を作成します.
鳥類と恐竜の化石の頭蓋骨構造を比較した分析

主要な成果:

イチヨルニス・ディスパールはの先まで狭く,口腔が欠けていた臨界のくちばしを持っていた.
この頭蓋骨は現代の鳥と比べられる運動システムを示しており鳥の特徴の初期の進化を示唆しています
比較的近代的な脳蓋にもかかわらずタイムラル領域は祖先の上部タイムラル・フェンストラの残骸を備えた恐竜の大きなアドゥクター・チャンバーを保持していた.

結論:

の運動を含む鳥の餌装置の重要な構成要素は,以前より早く進化し,機能的に統合された.
鳥類の脳の進化は祖先の恐竜のの筋肉と頭蓋骨の構造を保持したと同時に起こりました
鳥の進化のテンポとパターンの重要な洞察力を提供する原始的な頭蓋骨の特徴のモザイクを表しています

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