オステイクチアンのような枝状の弓を持つ古生代サメです
Alan Pradel1, John G Maisey1, Paul Tafforeau2
1Department of Vertebrate Paleontology, American Museum of Natural History, Central Park West at 79th Street, New York, New York 10024, USA.
Nature
|April 18, 2014
まとめ
3億2,500万年前の化石のサメは,原始的な門のアーチ構造を明らかにしています. この発見は,初期ののある脊椎動物 (gnathostomes) がこの祖先の特徴を共有していた可能性を示唆し,サメの進化に関する以前の理論に挑戦しています.
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
- 脊椎動物の解剖学について
背景:
- 内臓の枝状アーキの進化は,初期ののある脊椎動物 (gnathostomes) のの発達に決定的であった.
- 初期のグナトストームの内臓アーチについての理解は,限られた化石の証拠を持つ現代の魚に大きく依存していた.
- 新しい化石の発見は,祖先の特徴を明らかにし,進化論的仮説を洗練するために不可欠です.
研究 の 目的:
- 3億2500万年前の化石コンドリクシアンの内臓の弓の配置を説明するために.
- この化石の解剖学が,初期のグナトストームの進化に及ぼす影響を調査する.
- のある脊椎動物の門の祖先状態に関する理論を再評価する.
主な方法:
- 3億2500万年前のパレオゾイク時代のサメのような化石の記述.
- 完全な状骨格の3次元保存分析.
- 現代の軟骨魚や骨魚と比較した解剖学的分析.
主要な成果:
- 化石は,3Dで保存された完全な骨格を持つ,最も早く確認されたコンドリクシアンを表しています.
- その内臓の弧の配置は,オステイチアン (骨魚) のものに非常に似ています.
- このオステイキシアンのような配置は,冠状ギナソストームの祖先の条件を表している可能性があります.
結論:
- この発見は,オステイクシアンのような内臓の弓の配置が,の脊椎動物の祖先の条件かもしれないことを示唆しています.
- これは,現代のサメは最も原始的な門の特徴を保持しているという伝統的な見解に異議を唱えます.
- 初期のコンドリヒチアンは,の脊椎動物の進化史を理解するために重要である.
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