TRICONODON

genus of extinct primitive mammals found in Europe as fossil deposits of the Late Jurassic (163 to 144 million years ago). Triconodon is representative of the triconodonts, known throughout the world in regions as widely separated as North America, Europe, and China. Triconodon, a relatively large animal for its time (most early mammals were very small), was about the size of a domestic cat. The canine teeth were large and strongly developed, and it is probable that Triconodon was an active predator. The premolars were simple, but the molars had three distinctive cone-shaped cusps, hence the name. The brain was small and not much advanced beyond the brain of the mammallike reptiles. The relationships of Triconodon to later, more advanced mammals are uncertain. It is possible that the triconodonts had an independent reptilian origin and are best grouped or classified alone.