Cynognathus is an extinct genus of large-bodied cynodontian therapsids that lived in the Middle Triassic. It is known from a single species, Cynognathus crateronotus. Cynognathus was a 1.2-metre (3 ft 11 in) long predator closely related to mammals and had a southern hemispheric distribution.

Cynognathus evolved in the early Triassic Period (which began 251 million years ago). ... As the climate became more arid, the plant species upon which the prey of Cynognathus fed died out, and a (food) chain of events followed. Cynognathus became extinct sometime in the middle Triassic, about 215 million years ago.

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