It's in every dinosaur toy set, but it's NOT a dinosaur. Meet Dimetrodon, the apex predator that lived 40 million years before the first dinosaurs. That iconic sail? Likely a solar panel & status symbol for regulating body temperature and showing off. It's actually a "stem-mammal," a distant but important relative on our own evolutionary family tree. 🦴⚡ Retweet to confuse a friend: "Your favorite dinosaur is a proto-mammal." | Peter Dinolandia

Our journey to P.E.I.'s pre-historic age continues with geologist Laura MacNeil, as she describes the skull fossil of a Dimetrodon. | CBC Prince Edward Island

Exploring Dimetrodon: A Fascinating Synapsid Fossil