Mystery Event Decimated 90 Per Cent of Shark Diversity 19 Million Years Ago, New Study Finds Researchers say this unidentified event caused a reduction in shark diversity by over 70 percent and almost a complete loss in total abundance By Edited by Gadgets 360 Newsdesk | Updated: 5 June 2021 12:33 IST Photo Credit: Pixabay Highlights It led to the virtual disappearance of sharks from open-ocean sediments The cause of the event is still a mystery A new study has found that a single mysterious event about 19 million years ago wiped nearly the entire population of sharks. Scientists behind the new research say that studying the shark teeth buried in deep-sea sediment, revealed that the current diversity among sharks is only a tiny remnant of a much larger variety that existed back then. They say this unidentified major ocean extinction caused the reduction in the shark diversity by over 70 percent and nearly a complete loss in total abundance. The cause of this event remains a mystery, scientists said.