Casea

Casea is an extinct genus of pelycosaur synapsid which was about 1.2 metres (4 ft) long, slightly smaller than the otherwise very similar Caseoides. Casea was one of the first terrestrial herbivores, sharing its world with animals such as Dimetrodon and Eryops.

Description
Casea had a heavy, rotund, body and a small skull. Its rib cage was greatly expanded, presumably to make space for a large, plant-fermening gut. Like other caseids, it lacked teeth in its lower jaw, and had blunt teeth in the upper jaw. These adaptations indicate that Casea was a herbivore, feeding on relatively tough plants, such as ferns.