Deinocheirus is regarded as one of the most peculiar species of dinosaur. The true identity of this bizarre creature was a mystery for over four decades. However, at 36 ft long, Deinocheirus is now known to be the largest of the so-called ostrich dinosaurs It lived in Mongolia during the Late Cretaceous, 70 million years ago. History: When a pair of mysterious, giant arms were discovered in the Gobi Desert of Mongolia in 1965, they raised more questions than they answered. The discovery of more skeletons in 2009 provided the missing data needed to finally reconstruct Deinocheirus in its entirety. This new material was described in 2014 and revealed an even more unusual dinosaur than anyone had expected! Scientific Name: Deinocheirus mirificus Characteristics: Deinocheirus was an unusual, two-legged dinosaur with a small head, a humped back, and a long tail. The end of its skull expanded into a flattened bill and its teeth suggest that it may have been an omnivore.