Therocephalia

Therocephalia ("beast-head") is a suborder of carnivorous therapsids from the Permian and Triassic periods.

Description
Therocephalians had broad jaw muscles and reduced phalanges much like modern mammals. Most examples were likely endothermic and carnivorous, though some genera may have been herbivores instead.

It is possible that some therocephalians may have been at least partially aquatic.

Classification
Therocephalia is the sister group to Cynodontia, which includes all modern mammals. Both groups survived the Permian-Triassic mass extinction, but the therocephalians only persisted for a short time into the Triassic, while the cynodonts continued to diversify.

Below is a cladogram modified from a paper published by Adam K. Huttenlocker in 2014, showing the position of Therocephalia within the therapsids.

In popular culture
A group of unspecified therocephalians appeared in the third episode of the 2005 BBC documentary Walking with Monsters, stalking a herd of Lystrosaurus. In this series, they are depicted as being venomous. Although this feature was speculation, some therocephalian fossils show that such an ability may have been possible for certain species.

Venomous therocephalians also appeared in an episode of the ITV science fiction series Primeval.