Miocene (23 - 5.3 million years) - Pliocene (5.3 - 2.58 million years)
The Megalodon was the largest carnivorous fish in history which was estimated to grow up to 60 feet long and weigh up to 60 tons, making the Blue Whale the only living creature currently alive that was larger than it. The Megalodon was so large that it would also prey on whales. Reconstructions show their jaws could open up to 7 feet high and 6 feet wide and have up to 276 teeth.
The Megalodon existed up until the Pliocene era and went extinct due to climate and food source changes around 2.6 million years ago.