ホオジロザメがメガロドンの絶滅に貢献した可能性(Great white sharks may have contributed to megalodon extinction)

亜鉛の同位体を用いて、史上最大のサメ、メガロドンの食生活を調査しました Using zinc isotopes, researchers investigated the diet of megalodon, the largest shark to have ever lived

2022-05-31 マックス・プランク研究所

<関連情報>

• https://www.mpg.de/18712873/0527-evan-megalodon-extinction-150495-x?c=2249
• https://www.nature.com/articles/s41467-022-30528-9

亜鉛同位体比から明らかになったOtodus megalodonとホホジロザメの経時的な栄養的位置づけ Trophic position of Otodus megalodon and great white sharks through time revealed by zinc isotopes

Jeremy McCormack,Michael L. Griffiths,Sora L. Kim,Kenshu Shimada,Molly Karnes,Harry Maisch,Sarah Pederzani,Nicolas Bourgon,Klervia Jaouen,Martin A. Becker,Niels Jöns,Guy Sisma-Ventura,Nicolas Straube,Jürgen Pollerspöck,Jean-Jacques Hublin,Robert A. Eagle & Thomas Tütken
Nature Communications  Published:31 May 2022
DOI:https://doi.org/10.1038/s41467-022-30528-9

Abstract

Diet is a crucial trait of an animal’s lifestyle and ecology. The trophic level of an organism indicates its functional position within an ecosystem and holds significance for its ecology and evolution. Here, we demonstrate the use of zinc isotopes (δ⁶⁶Zn) to geochemically assess the trophic level in diverse extant and extinct sharks, including the Neogene megatooth shark (Otodus megalodon) and the great white shark (Carcharodon carcharias). We reveal that dietary δ⁶⁶Zn signatures are preserved in fossil shark tooth enameloid over deep geologic time and are robust recorders of each species’ trophic level. We observe significant δ⁶⁶Zn differences among the Otodus and Carcharodon populations implying dietary shifts throughout the Neogene in both genera. Notably, Early Pliocene sympatric C. carcharias and O. megalodon appear to have occupied a similar mean trophic level, a finding that may hold clues to the extinction of the gigantic Neogene megatooth shark.