The Dinosaurus (aka D. rex) is a species of Dinosaur that appears in the Dinosaur Island. It has it's own costume, and a skull of it is available as a furniture item. It is based off of the Tyrannosaurus rex. Judging by skull size it was likely around 80-120 ft. long, making it one of the largest animals in Club Penguin history.
It may have been ironically a herbivore (plant eater only.)
Judging by it's triangular shaped teeth, it is probably not, due to meat-eating animals (carnivores) having triangular teeth, plant-eating animals (herbivores) having square-shaped teeth, and those who eat both plants and animals (omnivores) having both types of teeth.