Issue Date: May 1, 1997
City: Grand Junction, CO
Quantity: 219,000,000
Printed By: Sterling Sommers for Ashton-Potter (USA) Ltd
Printing Method: Lithographed
Perforations: 11 x 11.1
Color: Multicolored

 

Some of the strangest Cretaceous creatures were a group of dinosaurs known as hadrosaurs. Plant eaters with duckbilled snouts, these dinosaurs also sported unusual crests and helmets on top of their heads. One of the most remarkable of these crests belonged to Parasaurolophus (PAIR-ah-SORE-ol-OH-fus).

 

Like other hadrosaurs, Parasaurolophus had powerful jaws lined with a spectacular array of diamond-shaped teeth that were used to grind the leaves of the conifer trees on which he fed. Believed to have attained a length of 30 to 33 feet and a weight of four to five tons, he walked upright on his hind legs, using his flat, broad tail to rest on while browsing. But the long, curved, bony tube that protruded back from his head set the Parasaurolophus apart.

 

When scientists cut the crest open, they discovered that it had several air passages connected to the nostrils.    By forcing air through the passages, a bellowing noise is created, causing some scientists to believe this crest was used as a resonator to sound alarms and attract mates. Others have suggested that the crest served as a defense mechanism, allowing the Parasaurolophus to spray a heated, chemical vapor, much as the bombardier beetle does today.