パレオセンのヒラコテレは,ポーレキャット・ベンチ・フォーメーション (ワイオミング州) のヒラコテレである
Science (New York, N.Y.)
|May 2, 1969
まとめ
ワイオミング州とバジャ・カリフォルニア州で発見された化石は,初期の馬 (エオヒッポス) がエオセーン時代以前に存在していたことを示唆しています. この発見は,ペリスソダクティラ (Perissodactyla) 系統が,これまで考えられていたよりも早く生まれたことを示している.
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
- ストラティグラフィー ストラティグラフィー
背景:
- 化石馬 (馬類) の地質学的記録は,伝統的にエオセンの時代まで遡られている.
- ペリスソダクティラ (奇爪類) の系統の進化的起源は,現在進行中の研究と推測の対象となっている.
研究 の 目的:
- 化石馬の既知の地質学的な範囲を Paleocene 時代後期まで拡張する証拠を提示する.
- ペリスソダクティルの起源と早期の拡散のタイミングを再評価する.
主な方法:
- 化石標本の古生物学的発掘と分析.
- 化石を含有する岩層のストラトグラフィック年代測定.
主要な成果:
- エオヒプス (Hyracotherium cf. Hyracotherium) の下を発見した. H. angustidens) は,ワイオミングの旧生代後半の層で発見されました.
- メキシコのバハ・カリフォルニア州で,おそらく旧紀後期の馬の歯を特定した.
- これらの発見は,化石馬の最も古い記録を,前エオセンの時代に押し戻す.
結論:
- オーダー・ペリスソダクティラ (Perissodactyla) は,以前から推測されていたよりも早く発生した可能性が高い.
- 初期のペリソダクティルは,北米全土に地理的に広範囲に広がり,エオセンの時代以前に存在していた.
- これらの発見は,パレオセン-エオセンの移行期における脊椎動物の分散パターンの再評価を必要とします.
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