Dimetrodon (/daɪˈmɛ.tɹəʊˌdɒn/) ("two measures of teeth"), was a predatory synapsid ('mammal-like reptile') genus that flourished during the Permian Period, living between 280 and 265 million years ago. It was more closely related to mammals than to true reptiles (Sauropsida), like dinosaurs, lizards and birds.
Dimetrodon was not a dinosaur, despite being popularly grouped with them. Rather, it is classified as a pelycosaur. It is surprisingly well-known to the general public and makes an appearance in the James Mason film Journey to the Center of the Earth, as well as in Yor, the Hunter from the Future. Fossils of Dimetrodon have been found in North America and Europe. The climate of Europe and North America in the Early Permian, was probably arid to continental, so Dimetrodon was probably adaptable.citation needed]