エルピストステージと脊椎動物の手の起源
Richard Cloutier1,2, Alice M Clement3, Michael S Y Lee3,4
1Université du Québec à Rimouski, Rimouski, Quebec, Canada. richard_cloutier@uqar.ca.
Nature
|March 28, 2020
まとめ
新しいエルピストステージワトソニの化石は,四足のような指を持つ胸の羽毛を明らかにし,脊椎動物の手は魚の羽毛から進化したことを示唆しています. この発見によって 魚と陸上の脊椎動物との境界線が 曖昧になりました
科学分野:
- 古生物学
- 進化生物学
- 脊椎動物の解剖学
背景:
- 魚から四足動物への移行は 脊椎動物の進化における重要な出来事です
- この変異の理解は 化石の証拠,特にエルピストステガリアン魚に 依存しています
- 以前のエルピストステガリアン化石には 完全な胸の骨格構造が欠けていました
研究 の 目的:
- エルピストステージ・ワトソニの完全な胸骨格を記述する.
- テトラポッドの四肢の進化に関連して エルピストステガリアの胸の骨格の配置を調査する.
- 魚の羽根と四足の間の 進化のつながりを明らかにするためです
主な方法:
- 大型のエルピストステージワトソニの採掘と準備.
- 詳細な骨格分析のための高エネルギーコンピュータトモグラフィー (CT) スキャン.
- 胸の骨格を比較した解剖分析
主要な成果:
- 1.57メートルのエルピストステージワトソニ標本. これまでに発見された最も完全なエルピストステージワトソニ標本.
- 胸の骨格には,近距離の4列の半径と,遠距離の2列の数字/推定数字があります.
- 羽根には,水生生物の移行形態を示唆する,遠端から放射状のレピドトリチアがある.
結論:
- エルピストステージの胸は 今までに発見された 四足類のような骨の配置を示しています
- 脊椎動物の手は エルピストステガリアン類の胸の内部の骨格パターンから 生まれているようです
- エルピストステージは他のすべての四足類の姉妹分類であり,魚と四足類の進化の連続性を強調しています.
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