Sharks were nearly wiped out by an unknown extinction event 19 million years ago – CNET

A previously unknown extinction event caused shark populations to collapse 19 million years ago.
Getty
When Earth’s temperatures spiked and oxygen levels in the ocean plummeted some 252 million years ago, most life on the planet was doomed. Some estimates suggest the extinction event, a mass extinction known as the Great Dying, killed off up to 70% of all land species but marine animals felt the impact even greater. As much as 96% of all species in the world’s oceans perished.
But not sharks. The…

Click here to view the original article.