Sign up for CNN’s Wonder Theory science newsletter. Explore the universe with news on fascinating discoveries, scientific advancements and more . CNN  —  Paleobiologist Dr. Kenshu Shimada has been fascinated by fossil sharks, including the giant Otodus megalodon, since childhood — he found his first megalodon tooth at 13 years old. So when he saw the 2018 blockbuster “The Meg,” he thought something was fishy. Not only did the movie depict the long-extinct megalodon surviving to modern times,