Mackerel sharks are a group consisting of some of the most iconic sharks we know, including the mako shark, the great white shark and Megalodon, the biggest predatory shark. Researchers found a unique feature in the teeth of these apex predators, which allowed them to trace back the origin of this group to a small benthic shark from the Middle Jurassic (165 mya).
Click here for original story, The ancestor of the great white shark
Source: ScienceDaily