Therocephalians ("beast-heads") are named after their large skulls, which, along with the structure of their teeth, suggest that they were successful carnivores. Like other non-mammalian synapsids, Therocephalians are described as mammal-like reptiles. They have also been shown to live and nest in large groups.
Therocephalians have a toxic and fast-acting venom which is injected into a victim with a bite. Symptoms include:
- Weakening of the body
- Bitten area on the skin turns reddish brown and black, then turns purple after death
- Death usually within a few minutes of contact.
A zookeeper attempts to run to the exit but takes a wrong turn and runs into the Reptile House. A Euchambersia jumps down from the roof and follows him. The zookeeper hears growling from behind him and turns around. As soon as he does, the Euchambersia jumps on him and kills him. Abby and Danny are searching for the creature that killed the zookeeper and are attacked by the Euchambersia. They manage to keep it from biting them by shooting at it with their EMD's. Connor tells Abby on her comm that the creature is a Euchambersia and Abby tells him she knows. Connor bolts out of the Reptile House and shoots the creature twice from behind, killing it. Connor unlocks the anomaly and Becker returns the dead therocephalian.
- The Therocephalians in Primeval Continued appear to be based on the Therocephalian in Tim Haines' previous production Walking With Monsters.
- The size of the Therocephalians in Episode 1.3 are slightly larger than real Therocephalians.
*The Therocephalian are shown with external ears, but actually they have internal ears, like lizards.