English: Deinocheirus was an unusual ornithomimosaur. It was the largest of the clade at 12 m long, and weighing around 6 t. Though it was a bulky animal, it had many hollow bones which saved weight. The arms were among the largest of any bipedal dinosaur with large, blunt claws on its three-fingered hands. The legs were relatively short, and also bore blunt claws. Its vertebrae had tall neural spines that formed a "sail" along its back and the skull had a wide bill and a deep lower jaw, similar to those of hadrosaurs. For nearly half a century, the massive arms were all that was known of Deinocheirus, which led to some speculation and confusion among the paleontological community.