Deinocheirus

Deinocheirus ("terrible hand") was a theropod dinosaur which existed in southern Mongolia throughout the Late Cretaceous time.The only known fossil leftovers are a single pair of massive, eight-foot-long (2.5 m) forearms with 10-inch long claws and the leftovers of some ribs and vertebrae.

Deinocheirus is measured by most paleontologists to be an Ornithomimid, as the structure of its arms is similar to other dinosaurs of the family. This would make Deinocheirus by far the biggest ornithomimid, at approximately 23-38 ft (7-12 m) long and weighing approximately 9000 kg. It may have been one of the greatest dinosaurs, able to run at nearly 40-50 mph. The fossilized arms are currently on show at the Paleontological Museum of the University of Oslo, Norway.