Labyrinthodont

Labyrinthodonts were large amphibious creatures which lived in the Palaeozoic and the early Mesozoic era.

Characteristics
The Labyrinthodont species from the Witchfield Cove incursion was a semi-aquatic carnivorous amphibian, which grew to be up to several metres long in adulthood. They possessed scaly grey skin, a large flattish head with two rows of teeth, small but powerful legs, and a long, serpentine or eel-like body. Due to its long, worm-like body, the Labyrinthodont was dangerously flexible and fast-moving on land. While juveniles were mostly harmless to large animals like humans, adult Labyrinthodonts were highly aggressive and dangerous, attacking and attempting to devour any prey in water or on land which drew its attention while it was hunting or were in its way. Adults were apparently highly protective of their young, willing to abandon helpless prey if they heard them call (which could apparently be heard from some distance away).

Real life
Labyrinthodont (name meaning "maze-toothed") was a subclass of amphibian which existed from 395 to 120 million years ago. It is ancestral to all terrestrial vertebrates.

Errors

 * The Labyrinthodont should have had smooth skin, not thick scales, covering its body.
 * The Labyrinthodont had upper and lower teeth in the series, but in real life they were smaller.
 * The labyrinthodont in the show looked like a worm salamander with crocodilian-like scales, but in real life, it was more like a regular salamander.
 * The Labyrinthodont was shown to be able to live very well out of the water, but in real life it would have needed to wet its skin from time to time.
 * The Labyrinthodont in Primeval was shown to have the ability to climb up things like trailers, but in the reality Labyrinthodont was strictly firmed to the ground.