Traversodontidae

Traversodonts were a group of herbivorous cynodonts. Their postcanine teeth were modified and expanded in width for chewing plants. Traversodonts had relatively wide snouts, and the maxilla extends sidewards beyond the teeth. This may indicate the presence of useful bags known as cheeks. Such devices allow for food to be more thoroughly chewed. Their skeletal features are much more mammal-like than the earlier therapsids. Early traversodonts had spines fitted with costal plates. These bits of bone overlapped with each other where the ribs met the back bone. These strengthened the spine, but what advantage that these provided is unclear. Such features are reduced in more basal traversodonts. The more advanced traversodontids (eg. Exaeretodon), did away with them entirely. This gives the spine a less clunky, more mammalian appearance. They may have laid eggs, like many other proto-mammals, and earlier synapsids. Traversodontids were abundant and successful during the world of the Middle and Late Triassic but were becoming less common before the Jurassic Period began. Around the time the Jurassic began, they became extinct probably due to competition with other animals such as dinosaurs, tritylodontid cynodonts and mammals.