Dicynodontia

Dicynodontia is an extinct clade of anomodonts, an extinct type of non-mammalian therapsid. Dicynodonts were herbivores that typically bore a pair of tusks, hence their name, which means 'two dog tooth'. Members of the group possessed a horny, typically toothless beak, unique amongst all synapsids. Dicynodonts first appeared in Southern Pangaea during the mid-Permian, ca. 270–260 million years ago, and became globally distributed and the dominant herbivorous animals in the Late Permian, ca. 260–252 Mya. They were devastated by the end-Permian mass extinction that wiped out most other therapsids ca. 252 Mya. They rebounded at beginning of the following Triassic, but subsequently declined during the Late Triassic and died out towards the end of that period. They were the most successful and diverse of the non-mammalian therapsids, with over 80–90 genera known, varying from rat-sized burrowers to elephant-sized megaherbivores.