鳥類の脳の進化的起源について
Amy M Balanoff1, Gabe S Bever, Timothy B Rowe
1American Museum of Natural History, Division of Paleontology, New York, New York 10024, USA. abalanoff@gmail.com
Nature
|August 2, 2013
まとめ
鳥のような脳の拡張は,恐竜に何度か進化した. アーキオプテリックスのような非鳥類マニラプトランでさえ,高度な脳形成を示しており,飛行能力は初期の鳥に特有のものではないことを示唆しています.
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
- 神経科学は神経科学である.
背景:
- かつて鳥にしか見られないと考えられていた羽と毛皮は,現在,鳥類以外の恐竜にも見られるようになった.
- 飛ぶために不可欠な鳥の超膨張した脳は,進化の歴史を完全に理解していない.
- 以前の研究では,鳥類の脳拡張は,熱足類の進化の初期に始まったと示唆されていました.
研究 の 目的:
- 鳥類の脳サイズと脳形成の初期の進化を調査する.
- 現存する鳥類,アーキオプテリックス,および非鳥類マニラプトランスの頭蓋骨の量を比較するために.
主な方法:
- 高解像度コンピュータトモグラフィー (CT) を使用して,頭蓋骨の体積を推定しました.
- 異なる恐竜群と鳥の間で頭蓋腔の容量の比較分析.
主要な成果:
- アーキオプテリクスの頭蓋腔の体積は,一般的なマニラプトランのサインと一致しています.
- アルカイオプテリクスの頭蓋腔は,他の非鳥類の恐竜よりも小さかった場合もある.
- 鳥類のような脳形成指数は,マニラプトラーンの中で独立して何度も進化した.
結論:
- 鳥類のような脳の膨張は,鳥の飛行以前のもので,収束的に進化した.
- アーキオプテリクスを含む非鳥類マニラプトランは,おそらく飛行のための神経学的能力を有していた.
- Avialansは,ある種の飛行能力を有するマニラプトラン類の中でユニークではありませんでした.
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