Diplocaulus

Diplocaulus was an ancient amphibian that lived in North America. It had a very strange head, with two "forked" projections sticking out of either side of it. It lived during the Late Permian Period, which was the last geological time period of the Paleozoic Era. Diplocaulus is often mistaken to be a dinosaur by the general public. However, just like Dimetrodon (another Permian creature, which is often thought to be a dinosaur), it was not even remotely related to any of the dinosaurs.

More real-life information: .

Jurassic Park Franchise

 * Diplocaulus has not appeared in any films or novels. It has, however, appeared in the spin-off video game Jurassic Park III: Park Builder.