Edaphosaurus

Edaphosaurus is one of the most important and one of the earliest known large plant-eating four-legged land-living vertebrates. 

It was named after its unusually dense cluster of teeth in its mouth and the Greek word edaphos / road/pavement. Another signature feature is the large sail on his back like the one of his more famous relative the Dimetrodon.

Edaphosaurus grew from 0.5 to nearly 3.5 metres long and weighed over 300 kilogrammes. Consistent with the tiny head, the cervical vertebrae are reduced, while the dorsal vertebrae are massive, the tail is deep, the limbs are short and robust, and the ribs form a broad thorax. Like most herbivores, Edaphosaurus possessed a spacious gut and symbiotic bacteria that helped it break down cellulose and other indigestible plant matter. Like its more famous relative Dimetrodon, Edaphosaurus had a sail-like fin supported by the bones of its spine. Edaphosaurus differs from Dimetrodon in the cross struts on the spines that supported its fin.