An “ultra (excessive) lizard” from Late Jurassic western Colorado, USA. Discovered in Colorado by dinosaur digger U. S. paleontologist James A. Jensen of Brigham Young University, this extremely large dinosaur was formerly known as Supersaurus. The name was changed to Ultrasauros because it was previously claimed for a South Korean specimen. Named by Korean paleontologist Haang Mook Kim in 1983.