Researchers at The Field Museum in Chicago, the North Carolina Museum of Natural Sciences and North Carolina State University unearthed a fossil of the giant that walked the Earth around 100 million years ago in the Cedar Mountain Formation in Utah, a Field release reported Friday.
"This dinosaur was a colossal predator second only to the great T. rex and perhaps Acrocanthosarus in the North American fossil record," Lindsay Zanno of the North Carolina museum said.
The dinosaur has been named Siats meekerorum, in reference to a cannibalistic monster from the mythology of the Ute Native American people and Field museum supporters the Meeker family.
Despite its large size, Siats is not a close relative of T. rex and other tyrannosaurs that were the dominant predators in North America for the last 20 million years of the age of dinosaurs, the researchers said.
Instead, they said, it belongs to the carchardontosaurian group of predatory dinosaurs whose more famous members include giants like the Argentinean Giganotosaurus.
Siats belongs to a branch of the carcharodontosaurian family tree that was previously unknown in North America, the researchers said.
"We were thrilled to discover the first dinosaur of its kind in North America and add to mounting evidence that dinosaurs were widely dispersed across the globe 100 million years ago" Field Museum dinosaur curator Peter Makovicky said.