Parasaurolophus

Parasaurolophus was a Hadrosaurid (duck-billed) dinosaur from the Late Cretaceous Period, approximately 76 to 73 million years ago. It is a famous dinosaur, known for its long, tube-like crest which was believed to be used as a communicative feature.

More real-life information: Parasaurolophus at Wikipedia.

Appearance
They are about 3.6 meters (12 feet) tall, 10 meters (33 feet) long and weighs 4-5 tons. They come in a grey or yellow coloration in either game.