dimetrodon
/daɪˈmɛtrədɑn/
noun
- An extinct reptile from the Permian period, known for the large sail-like fin on its back, often mistaken for a dinosaur.
- Unlike dinosaurs, the dimetrodon is actually a synapsid, more closely related to mammals.
- Museum visitors were amazed by the skeleton of a dimetrodon with its tall back spines.
- The dimetrodon lived long before the dinosaurs, during the Permian era.