Anomodontia is an extinct group of non-mammalian
therapsids containing many species from the
Permian and
Triassic periods (possibly continuing into the
Early Cretaceous), most of which were toothless
herbivores. Anomodonts were very diverse during the
Middle Permian, including primitive forms like
Anomocephalus and
Patranomodon and groups like the
Venyukovioidea, the
Dromasauria, and the
Dicynodontia. Of these only the dicynodonts survived beyond the Middle Permian. Dicynodonts became the most successful and abundant of all herbivores in the Late Permian and Triassic, filling ecological niches ranging from large browsers down to small burrowers. Few dicynodont families survived the
Permian–Triassic extinction event, but one lineage evolved into large, stocky forms that remained the dominant terrestrial herbivores right up until the
Late Triassic, when changing conditions caused them to decline.