A species of Therocephalian appears in episode 4.4. Numerous creatures the size of a large dog come through an anomaly at a school, and kill a teacher and a female student. Matt, Becker, and Connor deal with the venomous creatures, and Becker was bitten by one of the venomous creatures to paralyse him, but later recovered.
- These are the first prehistoric creatures to kill a child in Primeval.
- These are the second venomous creatures the show has featured, after the Arthropleura but are the first venomous creatures with actual evidence of having vemon in the show.
- The Therocephalians appear to range in size from a small dog to a wolf, as the ones that were sleeping near the Anomaly were a lot smaller than the one hiding in the vending machine (the ones sleeping near the Anomaly were likely younger).
- This the third mammal-like reptile the team has encountered.
- The Therocephalians in Primeval appear to be based on the Therocephalian in Tim Haines' previous production Walking With Monsters.
- They appear to be nocturnal and live in large family groups because in several parts they are seen sleeping together, even though it was bright outside (although they may have been suffering from "jet lag").
- No therocephalian has venom except for Euchambersia, so these therocephalians are probably Euchambersias.
- Based on the statement about the Therocephalians' venom that says that their venom is as deadly as the black mamba venom, it's reasonable to think that the Therocephalians in Primeval have a venom that is similar to that of a black mamba's.
- The Therocephalians are the only venomous vertebrate animals to appear in Primeval.
- The size of the Therocephalian that was hiding in the vending machine would not have allowed it to fit inside the vending machine.
- The size of the Therocephalians in Episode 4.4 are slightly larger than real Therocephalians.
- When Beth is killed, the attack would appear to have left large amounts of blood, but no trace of the attack is seen.
- However, this is normal for predators, even today. Most predators tend to leave very little evidence behind when they make a kill.
- The Therocephalian are shown with external ears, but actually they have internal ears, like lizards.