初期の marsupial について知られている marsupial は最も古い marsupial です
Science (New York, N.Y.)
|October 11, 1968
まとめ
最も古くから知られている袋類は,メタテリア類に属し,白亜紀中期アルビウス期の堆積物で発見された. テキサス州の化石証拠はまた,メタテリアとユーテリアの分岐が,以前理解されていたよりも早く起こったことを明らかにしています.
科学分野:
- パレオントロジー・パレオントロジー
- 脊椎動物学 脊椎動物学
- 進化生物学の進化生物学について
背景:
- メタテリア (マースピアル) の化石記録は,白亜紀中期より若い堆積物に限られている.
- 以前の理解によると,袋類は後に現れ,エウテリア (胎盤哺乳類) から分岐したと考えられていた.
研究 の 目的:
- 最も古い marsupial 化石の発見を報告する.
- メタテリアとユーテリアの間の初期の進化の分岐を調査する.
主な方法:
- テキサス州中北部にあるアルビアン鉱床の化石の発掘と分析.
- DidelphidaeとEutheriaファミリーの特徴を特定するための形態学的検査.
主要な成果:
- Didelphidaeファミリーの明確な特徴を示す化石素材は,Albianの堆積物から回収されました.
- エウテリアに関する遺跡も同じ場所で見つかりました.
- この発見は,袋類が以前に記録されたよりも古い堆積物の中に存在することを示しています.
結論:
- 発見された化石は,既知の最も古い有袋動物を表しており,その既知の起源を白亜紀中期に遡らせます.
- メタテリアとエウテリアの化石の共生は,これらの異種類が以前に確立されたよりも早く異なったことを示唆しています.
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