When dinosaurs ruled the land, a group of large marine reptiles called plesiosaurs ruled the seas. The pliosaurs were a part of this plesiosaur group. They measured up to 10 meters long (33 feet). These “water dinosaurs” had crocodile-like short-necked forms with fins, large heads and massive toothed jaws. With these tools they hunted almost anything they could find. Pliosaurs emerged over 200 million years ago, but didn’t turn into apex predators overnight. In fact, researchers aren’t exactly sure when they became a dominating force in the seas. This is where the new fossil comes in. An early…