|Scientific name||Unknown, Possibly Archegosaurus dechnie, Ichthyostega watsoni or Koolasuchus cleelandi|
|Home era||Late Paleozoic to Early Mesozoic (Late Permian to Early Triassic, maybe even Cretaceous)|
|Deaths caused|| 6+|
- "Get away from him!"
- ―Abby Maitland yelling at the Labyrinthodont to get away from Connor Temple[src]
Labyrinthodonts are short legged, large headed amphibians that lived from the Devonian to the Middle Cretaceous. They are very nasty predators, with the ability to rush out of the water and even attack things on land. In Primeval, this is shown, but in real life Labyrinthodonts would not be as fast as in Primeval. They would actually be slow and not very agile.
Several decades before the ARC was formed, an anomaly opened in a Seaside Cave near a beach, letting through two Labyrinthodonts. The Labyrinthodonts attacked and killed, many, many livestock and many, many people. In 2011, when a Boy camps at night on the headland, he hears some strange noises and records his data. However, he is attacked and killed by the Labyrinthodont.
At the river, the Labyrinthodont attacks a man and kills him (although this was not shown on screen). Matt later found body parts of the man. A man is fishing, and kneels down to turn the volume on his radio, but the Labyrinthodont in the river appears and dives back down. Matt arrives to the fisherman just as he catches his fish, but the Labyrinthodont takes it and attacks the man, but Matt shoots it with his EMD and it retreats back into the water.
Abby goes to a trailer park and finds the place in ruins as toys are other items are seen scattered. Abby finds two boys playing with water guns, but a toy is thrown by the Labyrinthodont and Abby goes to another caravan, and sees the Labyrinthodont. It rears up and lunges at her, throwing her back, making her loose her EMD. It turns around and chases a boy, who goes under a trailer, and as he tries to exit, it goes to his exit, only for Abby to unintentionally distract it and it goes for Abby, ramming into the caravan as Abby goes inside.
Abby tries to get out of the caravan into the outside world, but she can't open the door. She investigates the front of the caravan, but the creatures rams its head into the passengers window. Abby smacks it with an object and it attempts to climb on the the top of the caravan, but it can't, and instead goes ontop of the caravan. It rams its head into the moon roof, and snaps at Abby. Abby kicks it, but falls down.
Connor has arrived at the anomaly sight, and tells Abby to bring the creature to the cave, and she does so, with the Labyrinthodont on the caravan, trying to break inside. It eventually smacks the driver window, and knocks out Abby, and goes for Abby on the other side.
In the cave, Connor turns around to see a smaller Labyrinthodont screaming in pain as the acid from the farm is dumped ontop of the poor suffering animal. The screams attract the bigger Labyrinthodont to the cave, and it eats Abby's black box, but Abby is nowhere to be seen. It crawls off the caravan and heads to the cave.
At the cave, Connor is knocked out by the farmer and her son, and when he wakes up, she sees the small Labyrinthodont and finally believes in the "worm". But then, the bigger Labyrinthodont appears and kills both of them. Connor grabs a paddle and when the Labyrinthodont appears infront of him, and Jess says Abby is infront of him, he thinks the Labyrinthodont killed her, so he whacks it with the paddle, but soon he lets it go and it corners him.
It chases him around in the maze of rocks until it corners him for good and it attacks him, but then, a gun shot ripples. Connor finds himself to find Abby very well and very much alive, and she tries to shoot it, but petrol is all over the place, and it attacks her. Connor throughs a jug of oil at the anomaly, making it open up. The Labyrinthodont adult and the "baby" go through the anomaly back to their home era and the anomaly closes.
It is likely that the anomaly in the Seaside Cave reopened during Convergence and the Labyrinthodonts likely came back through and killed more people and livestock. It is likely that they went through another anomaly as well somewhere else around the world.
- This is the first Amphibian to appear in Primeval.
- It is unknown wether or not this creature is a Koolasuchus. it has two rows of teeth, scaly skin, and a body that is way too big to be a Koolasuchus. It is likely another creature, probably a Mastodonsaurus as it lived in Poland, but the body plan still doesn't work out. It is probably even more likely for it to be an undiscovered fictional species.
- If this was a fictional species, a good name for it would be Ichthyogyrinus.