Size and Weight:
Showing that surprises can lay in store for even the most experienced dinosaur hunters, the type fossil of Nothronychus was found in 2001 in the Zuni Basin on the New Mexico/Arizona border. What made this discovery especially significant is that Nothronychus is the first dinosaur of its kind, a therizinosaur, to be dug up outside Asia, which has prompted some quick thinking on the part of paleontologists. In 2009, an even bigger specimen--which has been assigned its own species under the Nothronychus umbrella--was unearthed in Utah.
Like other therizinosaurs, experts speculate that Nothronychus used its long, curved claws much like a sloth, to climb trees and gather vegetation (although classified as theropods, the therizinosaurs were strict plant-eaters, or at the very least omnivorous). However, other facts about this obscure, pot-bellied dinosaur--such as whether it sported primitive feathers--will have to await future fossil discoveries.