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プレイストセンの蛇・ウォンンビと蛇の初期の進化
1Department of Zoology, University of Queensland, Brisbane, Australia. jscanlon@ultra.net.au
Nature
|February 10, 2000
まとめ
Madtsoiidaeと呼ばれる化石ヘビは,ヘビの進化のヒントを提供します. 新しいWonambiの化石は,原始的な頭蓋骨の解剖学を明らかにし,蛇の地下起源説に異議を唱える.
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
- ヘルペトロジー ヘルペトロジー
背景:
- Madtsoiidaeヘビは,白亜紀からプレイストセーンまで9000万年間存在しました.
- 大陸の至る所で広く分布しているので,ヘビの進化についての洞察が得られます.
- Madtsoiidaeに関する以前の理解は,頭蓋骨の化石が少ないため,限られていた.
研究 の 目的:
- 後期に生き残ったマツゾイイドであるWonambiの頭蓋骨の解剖を分析するために.
- 蛇の進化におけるMadtsoiidaeの系統遺伝関係を決定する.
- 蛇の起源に関する地下理論を検証するために.
主な方法:
- 新しく発見されたオーストラリアのWonambiの化石素材の分析.
- 頭蓋骨の特徴の比較解剖学的研究.
- ウォンバンビや他の原始的なヘビを組み込んだ系統遺伝学的分析.
主要な成果:
- ウォンンビの詳細な頭蓋骨の解剖学が初めて解明されました.
- ウォンンビは,最近の年齢にもかかわらず,非常に原始的なヘビとして識別されています.
- ウォンンビ,パキラキス,ディニリシアを含む原始的なヘビの系統は,掘り込みの適応が欠けている.
結論:
- この発見は,蛇の地下起源説と矛盾している.
- 蛇の体型との器具は,穴を掘らない大きな祖先から進化した可能性が高い.
- 蛇の穴を掘る適応は,蛇の基本的な形態が確立された後,後で進化した.
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