Megalodon

Megalodon was a giant species of shark that swam the seas of Europe, North and South America, Africa, and Australia during the Miocene to Pliocene, dying out about 3 million years ago. Despite its iconic status, we know very little about the predator, lacking any skeletal material besides the teeth. Even the jaw bones have never been found. While some estimates put Megalodon at 80+ feet in length, new studies have brought it in at a more conservative 42 feet long.