Stylinodon mirus
Name Stylinodon mirus
Order Cimolesta
Suborder Taeniodonta
Family Stylinodontidae
Class Mammalia
Period Early-Middle Eocene
Location North America
Diet Herbivore, possibly omnivore
Length 2-3 metres (6-10 feet) long

Stylinodon is an extinct genus of taeniodont mammal, and is the best known, and last genus of taeniodonts, lived some 45 million years ago during middle Eocene in North America.

The skull suggests it had a blunt face, and a very short snout. Species ranged in size from pigs to leopards, reached a body mass of up to 80 kilograms (180 lb). Its canines had developed into huge, incisor-like root-less teeth. Stylinodon's molars were covered in enamel and continued growing throughout its life. Most likely, it fed on rough roots and tubers.

Stylinodon was a taeniodont which were among the most rapidly developed mammals after the extinction of the dinosaurs. They are probably related to the ancient primitive insectivorous animals, and from which they apparently occurred. The largest representatives, such as Stylinodon, reached the size of a pig, a leopard or a medium-sized bear, and weighed up to 110 kg. The front section of the skull had shortened the jaw muscles which were well developed. The canines have increased and expanded to the front, and they were covered with enamel, dentin, and the rear mild. The teeth had no roots and had a constant growth.

Taeniodonts like Stylinodon were strong muscular animals. On their five-fingered limbs, they had developed powerful claws adapted for digging. All of this suggests that they ate plant food (such as tubers, rhizomes, etc.), which is dug up from the ground with powerful claws. It is believed that they were active diggers, like foxes or badgers, and had a similar burrowing lifestyle. However, their diet, of course, was different; Taeniodonts were primitive animals with a poorly developed brain. They have been very successful in the Paleocene to the beginning of the Eocene, but eventually, they had to deal with more advanced mammals, which were adapted to similar ecological niches. They competed with them but the Taeniodonts could not. They, like many other primitive mammals (Paleocene - Eocene (tillodonts, pantodonts, dinocerates, etc), were only a temporary replacement in the niches of specialized and large herbivores.