Kingdom Animalia
Phylum Chordata
Superclass Tetrapoda
Class  ???
Order Therapsida
Suborder Cynodontia
Family Thrinaxodontidae
Genus Thrinaxodon
1st Species Thrinaxodon liorhinus
Other attributes
Time Range 251-247 mya
Location South Africa, Antartica
Name Meaning Trident tooth
Physical Dimensions 50 centimeters long
Dietary Classification Carnivore

Thrinaxodon is a thrinaxodontid therapsid synapsid from the Early-Middle Triassic of South Africa and Antarctica. It was named in 1894 by Harry Govier Seeley. It was a missing link between the more primitive synapsids of the Permian and the small mammals of the later Triassic, and is known to be a great survivor due to its burrowing habits.


Thrinaxodon resembled the generic cynodont, a therapsid with 4 semi-erect legs, a slender body, and a mid-sized head. Like all other cynodonts, its legs were more erect than those of the other therapsids. Its body would have been covered in fur.


Thrinaxodon was a predator, preying on insects, worms, small reptiles, and smaller cynodonts. Its small yet sharp teeth were used to get a hold of any struggling prey.


Thrinaxodon would have had a lifestyle similar to that of its more advanced mammal descendants: a small synapsid that hides in a burrow at day and only goes out to forage at night in order to steer clear of the early predatory dinosaurs that were the most active during daylight. In fact, it even had a few mammalian features, such as fur for insulation. As well as this, it had a few adaptations for living in a burrow; its legs are short and erect, its tail is short, and its body is much more long than it is wide. Not only does this allow it to slink through the tunnel of a burrow with ease, but it also allows for resting in comfortable positions in burrows, easily leading up to prolonged dormancy.

In popular cultureEdit

In the first episode of the 1999 documentary Walking with Dinosaurs, an unidentified cynodont is shown living in a burrow and only hunting at night in order to escape diurnal predators such as Coelophysis. Many people assume that this cynodont is Thrinaxodon; if this is so, then it would be heavily misplaced through time and space.

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