User:Peter M. Brown/Drafts

The most derived cynodonts are found within the clade Eucynodontia, which also contains the members of Mammalia. Representative genera of nonmammalian cynodonts include the large carnivorous cynognathids, equally large herbivorous traversodonts, and small and mammal-like tritylodontids and ictidosaurs. The presence of respiratory turbinates suggests a rapid metabolism and possibly endothermy.

During their evolution, the jaw of the cynodonts reduced the number of jaw bones. This move towards a single bone for the mandible paved the way for other bones in the jaw, the articular and angular, to migrate to the cranium where they function as parts of the mammalian hearing system.

Cynodonts also developed a secondary palate in the roof of the mouth. This caused air flow from the nostrils to travel to a position in the back of the mouth instead of directly through it, allowing cynodonts to chew and breathe at the same time. This characteristic is present in all mammals.