Ancestor

Cool.

"Paleontologists working in the desert wilderness of northwestern China have unearthed the oldest ancestor yet of Tyrannosaurus rex , a mid-sized, long-armed predator with razor-sharp teeth and a spectacular, inflatable crest atop its snout.

Unlike T. rex , however, Guanlong wucaii -- 'crown dragon from the land of five colors' -- was not the top-of-the-line predator of its time, but scientists suggested today that it could probably outrun anything it couldn't outfight.

'When you become a giant animal, the entire [body] has to be modified,' said American Museum of Natural History paleontologist Mark A. Norell. 'This is a very gracile [graceful] animal; T. rex is elephantine.'"