Ankylosaurus (meaning 'fused lizard') was an armoured, plant-eating, and one of the most well known dinosaurs. Although a complete skeleton has not been discovered and several other dinosaurs are represented by more extensive fossil material, Ankylosaurus is often considered the heavy built dinosaur. Other ankylosaurids shared its well-known features—the heavily-armored body and massive bony tail club—but Ankylosaurus was the largest known member of the family. Ankylosaurus was most well known by the distinctive knobs and plates of bone known as osteoderms, and had a club-like tail. It measured approximately 6.25 to 9 meters long, 1.5 meters wide and 3 meters tall, weighing about 3 to 6 tonnes. It first evolved in the Cretaceous period, 65 to 72 million years ago.
Ankylosaurus is seen a few times in the Primeval spin off novel Extinction Event. The first is when one plods harmlessly through the team's campsite. The Russian team, thinking these are going to harm them, start firing, only to prove that Ankylosaurus are resistant to gunfire. The animal later runs off uninjured. Later, Jenny and the soldiers accompanying her are almost killed after an angered Ankylosaurus hits the car they are in with its tail club after almost getting hit by the car. The car is badly broken and the driver is killed, but Jenny and her team survive. A mother and baby Ankylosaurus are later seen in the Cretaceous by the team.
- It is the twelfth largest creature encountered by the team.
- This is the only animal in which the young of the species are seen in its own Time Era.
- The colours of the Ankylosaurs in the past could be a reference to Walking With Dinosaurs.
- This is the second armored dinosaur to be encountered.
- It may have been the Huge Hippopotamus mentioned in Primeval Evolved.
- Ankylosaurus appeared in Walking With Dinosaurs along with Dromaeosaurus, Anatotitan, Torosaurus,and Tyrannosaurus Rex.