Dicynodontia

Dicynodontia is a major clade of herbivorous therapsids within the larger group Anomodontia, part of the order Therapsida. They arose in the Permian and became one of the most successful and diverse vertebrate groups of that era, with a global geographic distribution that included much of the southern continents.

The most distinctive feature of dicynodonts is their beaked mouths, formed by the premaxilla and maxilla, used for cropping vegetation. In many species, one or two large tusks (enlarged canine teeth) protruded from the upper jaw, giving rise to the name dicynodont, meaning “two dog teeth.” Most dicynodonts lacked post-crown cheek teeth, and their skulls and jaw joints show adaptations for a herbivorous diet. Many species show a robust, sometimes barrel-shaped body and a sprawling to semi-erect gait.

Ecologically, dicynodonts were diverse in size and lifestyle. They ranged from small burrowers such as Diictodon to large, stocky herbivores. They occupied a variety of habitats and are often interpreted as important components of Permian to Triassic terrestrial ecosystems, with some forms possibly able to exploit tough vegetation or underground resources.

Fossil record and distribution extend from the Middle Permian to the Late Triassic, with especially common remains in Gondwanan deposits (Africa, India, Antarctica, Australia, and South America) and also in Europe and North America. Lystrosaurus, a well-known Early Triassic dicynodont, exemplifies their post-extinction success. Most dicynodonts went extinct by the end of the Triassic, making them an important group for understanding Permian–Triassic ecological dynamics and faunal turnover.