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最も古くから関節のあるオステイクチアンは,モザイクグナトストームの文字を明らかにしています
Min Zhu1, Wenjin Zhao, Liantao Jia
1Key Laboratory of Evolutionary Systematics of Vertebrates, Institute of Vertebrate Paleontology and Paleoanthropology (IVPP), Chinese Academy of Sciences, PO Box 643, Beijing 100044, China. zhumin@ivpp.ac.cn
Nature
|March 28, 2009
まとめ
シルル紀期の新しい,ほぼ完全な魚の化石は,骨魚 (オステイクシアン) との脊椎動物 (グナトストーム) の初期の進化に光を当て,予期せぬ特徴を明らかにしています. この発見は,重要な進化の分裂のタイムラインを後押しする.
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
- 脊椎動物学 脊椎動物学
背景:
- オステイクシアン (骨魚と四足類) の進化はシルウリア時代まで遡るが,証拠は断片化された化石に限られている.
- 初期のグナトストーム (状脊椎動物) の進化を理解するには,より完全な化石記録が必要です.
研究 の 目的:
- シルリア紀のルドロー時代から新しく発見された,例外的に保存された原始魚を記述するために.
- 化石の頭蓋骨の後部骨格を分析し,初期のオステイクシアンとサルコプテリジアン進化の洞察を得るために.
- アクチノプテリジアン-サルコプテリジアン分裂の最低日付を定めること.
主な方法:
- 中国の云南省で化石の発見と発掘.
- 保存状態が非常に優れた化石魚の詳細な形態学的分析.
- 既知の基礎サルコプテリジアンと非骨格類のグナトストームを用いた比較解剖学的研究.
主要な成果:
- 最も古い,ほぼ完全なグナトストームの発見,中国の云南のラッドローの原始的な魚.
- この化石は,原始的な特徴 (胸帯,中の脊髄) と派生的な特徴 (マクロメリック・スクワメーション) の混合を示している.
- この組み合わせは,Psarolepis.pis.のような基礎サルコプテリジアンに関する以前の発見を裏付けている.
結論:
- この新分類は,最も古い関節性サルコプテリギアを代表し,オステイチアンの起源に関する重要なデータを提供します.
- この発見は,アクティノプテリジアン-サルコプテリジアン分裂が,最長4億1900万年前に起こったことを示しています.
- この発見は,初期の脊椎動物の進化のモザイク的な性質を強調しています.
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