タリモンストラムの目には 脊椎動物との親和感が表れています
Thomas Clements1, Andrei Dolocan2, Peter Martin3,4
1Department of Geology, University of Leicester, Leicester LE1 7RH, UK.
Nature
|April 14, 2016
まとめ
謎めいたタリーモンスター (Tullimonstrum gregarium) は脊椎動物として特定されています. 化石化した目の分析は 独特のメラノソームを明らかにし 脊椎動物だけが共有する 重要な特徴です
科学分野:
- 古生物学
- 進化生物学
- 脊椎動物学
背景:
- タリモンストラム・グレガリアムは マゾン・クリークの炭鉱期化石で 数十年もの間 系統遺伝学的な分類に 異議を唱えてきました
- 以前の研究では,モルラスカ,アネリダ,コルダタとの関連が提案され,その親和性を決定することができなかった.
- 明確な同型解剖学的証拠の欠如は 確実な体系的な配置を妨げました
研究 の 目的:
- タリモンストラム・グレガリアムの 系統遺伝を決定する
- タリモンストラムの目の 超構造的な詳細を調査する
- 化石のメラノソームが 系統遺伝信号を提供できるかどうかを確かめるため
主な方法:
- 化石化した目の解剖学的分析のためのスキャニング電子顕微鏡 (SEM).
- マイクロボディを特定するための飛行時間二次離子質量スペクトロメトリ (ToF-SIMS).
- 微生物の化学的サインを分析する多変量統計
主要な成果:
- タリモンストラムの目には,球形と円筒形のメラノソームの異なる層を持つ網膜があります.
- ToF-SIMSと統計分析は これらの微生物がメラノソームであることを確認した.
- 2つの異なるメラノソーム形態の層構造は脊椎動物のシナポモルフィーである.
結論:
- 脊椎動物特有のメラノソーム構造がTullimonstrumに存在することは,それが脊椎動物であることを示す.
- 化石のメラノソームは色や生態系を超えて 系統遺伝情報を保存できます
- タリモンストラムは,脊椎動物の総集団の中で,解剖学的に珍しい脊椎動物を表しています.
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