Anthodon serrarius (Owen 1876) Late Permian ~255 mya, 1.2-1.5 m long was a basal pareiasaur. Derived from sisters to Stephanospondylus. Anthodon was a sister to Arganaceras, Deltavjatia and other pareiasaurs like Bradysaurus.
Distinct from Stephanospondylus, the skull of Anthodon had anterior-facing nares on a broader skull. Very large quadratojugal "horns" expanded below the orbit. The mandible developed ventral protrusions. The teeth were all smaller and more uniform in size, each with 8 to 15 cusps. The postparietals were fused and, along with the tabulars, were located on the skull roof, as in more primitive diadectomorphs.
More vertebrae were cervicalized. No dorsal ribs were expanded with costal plates. The tail was further shortened.
The scapula developed an acromion process. The manus and pes were smaller with shorter, disc-like phalanges. The ilium was much taller which dropped the pubis and ischium providing a deeper gut. The tarsus was fused.
Small osteoderms covered the dorsal trunk as in Sclerosaurus. |
