The record showed a 40-million-year period of relative stability, during which the ratio of shark to fish parts in the fossil record hovered at 1 to 5. The discovery was made by researchers from Yale University and the College of the Atlantic in Bar Harbor, Maine, who were compiling an 85-million-year fossil record of shark abundance in order to gain a greater understanding of how their population varied over vast swathes of time. Now, the results of a recently published study have revealed a new chapter in the history of these ancient predators, during which time their population was devastated on a global scale. They are an extraordinarily resilient form of life that has endured numerous extinction events, and are now among the apex predators in Earth’s modern oceanic world. Sharks and their ancestor species have been swimming Earth’s oceans for the past 450 million years. It is currently a mystery as to what happened to the shark population, but the study authors say the event saw sharks almost entirely disappear from the open ocean in its wake. Scientists have discovered a hitherto unknown mass extinction event that decimated the global shark population some 19 million years ago.
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