This week’s “Fossils in Focus” I'm taking us back to the Late Cretaceous seas, where the mosasaur ruled as one of the top predators under the waves.
Mosasaurs weren’t actually dinosaurs - they were actually marine reptiles, more closely related to modern monitor lizards and snakes. The name means "Meuse-Lizard" named after the Meuse river in the Netherlands where fossils of the monster were first found. Imagine a cross between a crocodile and a komodo dragon, stretched out and with flippers, engineered for success in the oceans. These apex hunters could reach lengths of over 15 metres, with double-hinged jaws and teeth built for crunching anything from fish to other marine reptiles.
I’ve sketched a mosasaur from a cool render I found online this week to give an idea of how this terrifying beast may have appeared when hunting. The scale is off slightly, but it does make him look extra mean! Just picture this thing patrolling the seas while dinosaurs like Triceratops and T. rex roamed the land above.
Mosasaurs are known from spectacular fossils, including some that preserve impressions of their skin, showing they had smooth, scaly hides. Fossilised stomach contents even reveal their last meals — from turtles to ammonites, showing they weren’t picky eaters. We have nice large sized teeth currently available if you want to grab yourself a momento of this part of Earths history.
Fun fact: Mosasaurs could expand their jaws much like snakes, allowing them to swallow huge prey whole. If you’ve seen Jurassic World, you’ll remember the one that leapt out of the water for a very dramatic shark snack!
