Tiny T-Rex (broadcast Friday, September 18th, 2009)

University of Chicago paleontologist Paul Sereno adds the toe claw to a well preserved skeleton of the new tyrannosaur Raptorex. Photo by Mike Hettwer.

Scientists report the discovery of a dinosaur that could have been a scale model of the fearsome Tyrannosaurus Rex. Raptorex kriegsteini, found in China, appears to predate T. rex by tens of millions of years, yet shares some of T. rex's most notable traits, such as a large skull and tiny forearms attached to a tremendous body. The pint-sized predator was about 9 feet in length and weighed about as much as a human. We'll talk with paleontologist Paul Sereno about the find, reported this week in the journal Science.