Sporting jaws full of fearsome teeth and a massive fin on its back, Dimetrodon lived nearly 300 million years ago during the Permian period. Usually identified in popular culture as a dinosaur, Dimetrodon was actually a “mammal-like reptile” that died out some 40 million years before the first dinosaurs even appeared. Reaching lengths upward of 13 feet, Dimetrodon probably hunted reptiles and amphibians on land near water, though some scientists believe it lived an aquatic or semi-aquatic existence.

Aurora #745, Sail Back Reptile (Dimetrodon)