(Image Credit: The Field Museum/AP Photo)

Meet the biggest bully from 100 million years ago that even rivaled the mighty tyrannosaurus rex.

The discovery of the siats meekeroreum (pronounced see-atch), a new dinosaur species, was announced today by Chicago's Field Museum of Natural History.

The partial skeleton of the meat-eating predator, which weighed more than four tons and was 30 feet long, was found by paleontologists in Utah's Cedar Mountain Formation in 2008.

After years of careful excavation and cleaning of the fossils, the new species was officially announced today.

"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" Peter Makovicky, curator of dinosaurs at the Field Museum, said in a statement.

Paleontologists also found tyrannosaurs teeth near the siats fossils, they said, indicating that the T-Rex was smaller in stature and did not compete with the newly discovered species for a top predator role.