Before T. Rex, This Dinosaur Was King

Earlier this month, we heard tell of the "king of gore"; now researchers have discovered another top dino that lived before Tyrannosaurus rex. About 98 million years ago—31 million years before tyrannosaurs—there was Siats meekerorum, whose bones were found recently in Utah. The onetime top predator walked on two legs and may have weighed four tons; its length may have rivaled a school bus. The figures aren't totally clear because the remains researchers found belonged to a juvenile.

Working at Utah's Cedar Mountain Formation, researcher Lindsay Zanno and her team found Siats' vertebrae, toes, lower leg, and hip parts. "A juvenile Siats would have been, at minimum, about 30 feet long and around 9,000 pounds," says Zanno. That "puts juvenile Siats as the third largest predator ever discovered in North America," and "future material may reveal Siats grew up to be one of the biggest predators known around the globe." Siats' genus name comes from the name of a vicious creature of native Ute tribe legend, National Geographic reports. (More Tyrannosaurus rex stories.)