The 15-foot-long beast has been dubbed Nasutoceratops titusi, for its huge nose and exceptionally long horns, features unlike any other triceratops previously known, they said.
"This dinosaur just completely blew us away," Mark Loewen of the University of Utah told BBC News.
"We would never have predicted it would look like this -- it is just so outside of the norm for this group of dinosaurs."
"The horns are by far the absolute largest of any member of its group of dinosaurs -- they curve sideways and forwards," he said. "In addition it has the biggest nose of its group too."
Despite the fearsome look provided by the long horns and prominent nose, Nasutoceratops was a herbivore like all triceratops, the researchers said.
Nasutoceratops lived on Laramidia, an isolated landmass formed when a shallow sea flooded central North America during the Cretaceous period about 75 million years ago, they said.