Dimetrodon

Dimetrodon (meaning "two measures of teeth") is an extinct genus of synapsid that lived during the Early Permian Period, around 295–272 million years ago. It is a member of the family Sphenacodontidae. The most prominent feature of Dimetrodon is the large sail on its back formed by elongated spines extending from the vertebrae. It walked on four legs and had a tall, curved skull with large teeth of different sizes set along the jaws. Most fossils have been found in the southwestern United States, the majority coming from a geological deposit called the Red Beds in Texas and Oklahoma. More recently, fossils have been found in Germany. Over a dozen species have been named since the genus was first described in 1878

Description
Dimetrodon was a quadrupedal, sail-backed synapsid. Most Dimetrodon species ranged in length from 1.7 to 4.6 metres (5.6 to 15.1 ft) and are estimated to have weighed between 28 and 250 kilograms (62 and 551 lb). The largest known species of Dimetrodon is ''D. angelensis at 4.6 metres (15 ft) and the smallest is D. teutonis'' at 60 centimetres (24 in). The larger species of Dimetrodon were among the largest predators of the Early Permian, although the closely related Tappenosaurus, known from skeletal fragments in slightly younger rocks, may have been even larger at an estimated 18 feet (5.5 m) in total body length.