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巨大な幹四足動物は,ゴンドワナ氷河期後半の頂点捕食者でした
Claudia A Marsicano1,2, Jason D Pardo3, Roger M H Smith4,5
1Universidad de Buenos Aires, FCEN, Departamento de Cs. Geológicas, Buenos Aires, Argentina. claumar@gl.fcen.uba.ar.
Nature
|July 3, 2024
まとめ
ナミビアで発見された 巨大なテトラポッドの化石は 初期のテトラポッドの進化論に 異議を唱えています この発見は,炭鉱時代からペルミア期への移行期に大陸の四足類がより広く分布していたことを示唆している.
科学分野:
- 古生物学
- 進化生物学
- 脊椎動物 古生物学
背景:
- 現在の仮説は,初期の四足類の進化を炭鉱期の赤道湿地と結びつけている.
- これらの仮説を支持する化石の記録は,主に古方位パンゲア (ローラシア) に限定されている.
- 過去のモデルでは カーボン期後半に 急速な生息環境の移転と分散が 示唆されている.
研究 の 目的:
- 高緯度初期のペルミアン期の 巨型四足類の化石について説明します
- 初期の四足類の分布と進化に関する既存の仮説に挑戦する.
- 大陸の四足類の分布を 証明するために
主な方法:
- 化石の記述: 骨格と頭蓋骨の特徴を含むガイアシア・ジェンニエ
- ゲアシアの進化の位置を 調べるため
- 古代地理学的再構築と既存の化石データとの比較
主要な成果:
- ペルミア初期 (280万年前) のナミビア (55°S) の大きな幹四足類であるガイアシア・ジェンニエの発見.
- ガイアシアは独特の頭蓋骨の特徴を示します 骨が弱い頭蓋骨 ダイヤモンドの形状のパラスペノイド 歯が大きくなる
- 系統遺伝分析では,ガイアシアを炭鉱科コロステイダの姉妹分類に分類している.
- ガイアシアは,ゴンドワナの寒冷温度の緯度におけるテトラポッドの存在を示唆する,知られている最大の桁の茎テトラポッドである.
結論:
- 高緯度ゴンドワナのガイアシアの発見は,初期の四足体の進化の赤道中心の見解に異議を唱える.
- 大陸の四足類は,炭鉱期からペルミア期への移行期に様々な古気候地帯で形成された.
- 世界的な四足動物の周回と分散に関する既存の仮説は,高緯度データを組み込むために修正する必要があります.
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