<i>Platecarpus</i> Illustration (IMAGE) Natural History Museum of Los Angeles County Caption One of the ocean’s most formidable marine predators, the mosasaur Platecarpus, lived in the Cretaceous Period some 85 million years ago and was thought to have swum like an eel. Mosasaurs were lizard-like in appearance and known for their ferociousness. Credit Illustration by Stephanie Abramowciz, NHM Dinosaur Institute Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.