ペラジックサメの初期ミオセンの絶滅

Elizabeth C Sibert^1,2,3, Leah D Rubin⁴

¹Harvard Society of Fellows, Harvard University, Cambridge, MA 02138, USA. elizabeth.sibert@yale.edu.

Science (New York, N.Y.)

|June 4, 2021

まとめ

大規模なサメの絶滅は1900万年前に発生し,その数は90%以上減少し,多様性は70%以上減少した. この古代の海洋捕食者の危機は海洋生態系を再構成しました

科学分野:

古生物学
海洋生物学
海洋学

背景:

サメの個体数は過剰漁獲や人為的なストレスから現代的な脅威に直面しています
海洋捕食者の変化の長期的影響は十分に理解されていません.
過去の研究では古代の大規模なサメの絶滅を特定できませんでした

研究の目的:

以前未知の大規模なサメの絶滅を特定し特徴づけること
古代のサメの減少の時期と規模を決定するためです
初期ミオセンのオープンオーシャン生態系への影響を理解するために

主な方法:

初期ミオセンのオープンオーシャン堆積物におけるサメの豊富さと形態学的多様性の分析
絶滅の相関関係と既知の地球規模の気候現象
絶滅のタイミングと後の捕食者の多様化を比較する.

主要な成果:

大規模なサメ絶滅の証拠約1900万年前 (ミオセンの初期)
サメの数は90%以上減少し形態学的多様性は70%以上減少しました
この絶滅は既知の地球規模の気候現象とは無関係で主な捕食者の多様化に先立ちました

結論:

初期のミオセンは,開いた海の生態系にとって重要な変化を遂げ,サメの個体数が大幅に減少した.
この古代の絶滅は海洋捕食者の動態を根本的に変えました
サメは絶滅前の豊富さや多様性を回復していません

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