Cotylorhynchus

Cotylorhynchus is an extinct genus of herbivorous caseid synapsids that lived during the late Lower Permian (Kungurian) and possibly the early Middle Permian (Roadian) in what is now the states of Texas and Oklahoma. The large number of specimens found make it the best-known caseid.

Like all large herbivorous caseids, Cotylorhynchus had a short snout sloping forward and very large external nares. The head was very small compared to the size of the body, which was massive, barrel-shaped, and ended with a long tail. The barrel-shaped body must have housed large intestines, suggesting that the animal had to feed on a large quantity of plants of low nutritional value. The limbs were short and robust. The hands and feet had short, broad fingers with powerful claws.