Mesogog

Mesogog is a genetically altered creature intent on returning the Earth to the rule of the Dinosaurs. He is an elegant and civilised creature, much unlike the average dinosaur.

Anton Mercer is the unwilling host of Mesogog- unable to control when he transforms and hindered with his evil influence. Mesogog was born thanks to Mercer's genetic experiments with Dinosaur DNA. 

When Mesogog grew tired of Mercer's meddling, he set about seperating their bodies. Mesogog was far more powerful, and eventually mutated into his final form.

He was first defeated by Conner's Battilzer on full power, but he was able to come, and replicate himself. The five Rangers joined together, and united their Dino Gem energies to finish him for good.