Kevin Terris found the fossil while visiting the Grand Staircase-Escalante National Monument in southern Utah in 2009.
"At first I was interested in seeing what the initial piece of bone sticking out of the rock was," Terris said. "When we exposed the skull, I was ecstatic!"
Scientists nicknamed the fossil "Joe" after subsequent excavation and cleaning. A study of the fossil determined that Joe was the most complete specimen yet known for Parasaurolophus (pronounced PAIR-uh-SORE-AH-luf-us), a hadrosaurid, or duck-billed, dinosaur that lived throughout western North America around 75 million years ago.
The Cretacious-era herbivores are best known for their tube-shaped crests, which scientists speculate were used like a trumpet to blast sounds for communication.
Although scientists have studied Parasaurolophus skeletons for the past 90 years, the new discovery will shed light on how the species grew.
Researchers have made 3D digital scans of the entire fossil -- available for free at Dinosaurjoe.com. This is the first time an entire skeleton has been posted online in this format.
The study describing the new fossil was published Wednesday in the open access scientific journal PeerJ. The specimen is currently on exhibit at the Raymond M. Alf Museum of Paleontology in Claremont, California.