length) from some of the most iconic predators of the ancient seas: Mosasaur – A huge, cone-shaped tooth from the fearsome marine reptile that ruled the oceans in the Late Cretaceous. Otodus obliquus – A sharp, triangular shark tooth from one of the top predators of the Paleogene seas, related to the great white shark. Squalicorax – Known as the 'crow shark,' this tooth comes from a Cretaceous shark famous for both hunting and scavenging. Spinosaurus- Spinosaurus is an extinct, large, carnivorous dinosaur known for the tall spines on its back that formed a "sail," which translates to "spine lizard Enchopristis – A rare tooth from a sawfish-like ray with a long, spiked snout, dating back to the Cretaceous period. Enchodus – Often called the 'saber-toothed herring,' this fish had striking, fang-like teeth.