"It's been a dream summer for paleontologists," said Alan Titus, paleontologist for the 1.9 million-acre monument in southern Utah.
A 6-foot-long skull of one of the creatures, found intact, belongs to a beast similar to members of the ceratoid family, but has some distinctly unique features.
"We realized from its features and characteristics we've never seen it before," Titus said.
The combination of different characteristics about the skull, he added, make it impossible to categorize in the two subfamilies for ceratoid dinosaurs, known for facial horns and a shield that fans out from the back of the neck.
What makes the creature unique are the large horns over the eyes and stubby horn over the nose in addition to features of the shield, Titus said.
The skull was found this summer by a volunteer.
About a week before that discovery, the same group found the full skeleton of another ceratop-like dinosaur, including a partial skull, that also defies known species.
Fossilized skin impressions also were found, which can help tell about the anatomy of an animal more than bones alone.
Titus credited the discovery to a group of paleontologists unearthing other fossils on a remote area of what is known as the Kaiparowits Formation on the Kaiparowits Plateau.
He said the full skull was discovered when a volunteer walked off and found an interesting-looking bone exposed on the ground. It turned out to be a bone that connects the skull to the neck.
Scott Richardson, who found the skull, said he had just finished a 12-week internship sponsored by the Geological Society of America's GeoCorp program, and was visiting the paleontologist camp Aug. 21 before leaving for the summer.
"They were working on some hadrosaur skulls and had everything under control, so I decided to do some prospecting," said Richardson from his home in Flagstaff, Ariz. "I'd only gone about 200 yards away and found a few pieces of bone sticking above the ground,"
After brushing off the bones, Richardson said he realized what kind of bone it was and told Mike Getty of the Utah Museum of Natural History.
"[Getty] said the skull was unique and the best specimens to ever come off of the monument," Richardson said.
Titus said the skull is the most important fossil to find for identifying a new species.
For some reason, he added, the brain buckets of dinosaurs evolved faster than any other part of the creatures.
The specimens, now covered in protective plaster jackets, will be airlifted out of the remote area as soon as a helicopter is located large enough to lift the bones.
Titus said they will be sent to the Museum of Natural History in Salt Lake City for further study.
"They'll want to write an article on these for a prestigious publication."