TheriodontiaThe`ri*o*don"ti*a\, n. pl. [NL., fr. Gr. ? (dim. of ? a beast) + ?, ?, a tooth.] (Paleon.) An extinct order of reptiles found in the Permian and Triassic formations in South Africa. In some respects they resembled carnivorous mammals. Called also Theromorpha. Note: They had biconcave vertebr[ae], ambulatory limbs, and a well-developed pelvis and shoulder girdle. Some of the species had large maxillary teeth. The head somewhat resembled that of a turtle. The Dicynodont is one of the best-known examples. See Dicynodont.