Fossils of the meat-eater's hand-like claw and foot were found in the Grand Staircase-Escalante National Monument near the Arizona border, giving paleontologists reason to believe some dinosaurs known as raptors roamed from Canada to northern New Mexico about 75 million years ago.
Much smaller variations of the dinosaur had been found previously in Montana, South Dakota and the Canadian province of Alberta.
"This is the southernmost occurrence of this group, and it's about two times the size of the ones up north," said Lindsay Zanno, a doctoral student at the University of Utah who named the dinosaur Hagryphus giganteus, or giant four-footed, birdlike god of the Western desert.
The dinosaur had a strong toothless beak, powerful arms and formidable claws that made it capable of eating animals and plants. Large feathers grew on its hind end, giving it a resemblance to a turkey, Zanno said.
Scientists are not sure what purpose the feathers served, but it was not for flying. "It's quite different from modern birds," she said.
Mike Getty, collections manager at the university's Museum of Natural History, found the fossils in 2001. Scientists needed several years to excavate the fossils and publish their findings, he said.
The dinosaur was named in a paper published in December by the Journal of Vertebrate Paleontology. It was the first new dinosaur from the national monument to receive a name.
"This is the last great, unexplored dinosaur bone yard in the lower 48 states," said Scott Sampson, the museum's chief curator who wrote the journal article with Zanno.
Three other dinosaurs discovered at the monument are expected to be named soon, Sampson said, including a meat-eating tyrannosaur, a horned dinosaur and a duckbilled dinosaur with a 7-foot-long head.