Watching "Primeval" is often a crash course in the lesser-known animals of the prehistoric world. For example: The pilot features a Gorgonopsid. It's not only the first prehistoric creature to be seen on screen, it's the first creature of any sort -- he actually makes his debut before this first human on screen. However, chances are that few of the dinosaur-lovers you know would count this guy among A-listers such as the T. Rex, the Stegosaurus and the Triceratops.
But what there's to know about this beast?
The Gorgonopsid belongs to the order Gorgonopsia, literally meaning "Gorgon face." If you know anything about Greek mythology, then you know that the famously ugly Medusa is a Gorgon, and therefore the name "Gorgon face" is not a complement about this creature's physical appearance. They're also classified as theriodonts, which literally means "beast tooth" but which isn't intended as a slam against their chompers, despite how it sounds.
Looks aside, the Gorgonopsid has been considered by some scientists to be a "mammal-like reptile", though that classification is based on specific anatomical structures -- like differentiated teeth -- and not milk production. According to Wikipedia, the Gorgonopsid was one of the largest meat-eating animals roaming the earth in the late Permian period -- around 260 to 250 million years ago. Also, despite how it looks onscreen in "Primeval," scientists actually aren't sure whether it had fur, scales or smooth skin.
For more info on the Gorgonopsid as it appears in "Primeval," read its entry on the Primeval Wiki.