Jun 3, 2021 Scientists studying the fossil record found in deep-sea sediments stumbled upon a rather strange discovery when they noticed that the planet's shark population inexplicably plummeted around 19 million years ago. The puzzling find reportedly occurred as researchers were attempting to construct an "85-million-year-long record of fish and shark abundance" by way of microfossils found in deposits of mud that were unearthed during deep-sea drilling operations. While combing over this ancient material, they were left scratching their heads when they spotted a peculiar change in the shark population that defies explanation.