Comparison of skulls: Raptorex skull (foreground) is dwarfed by that of its descendent Tyrannosaurus rex.Courtesy Paul SerenoA new meat-eating dinosaur that looks like a scaled-down version of Tyrannosaurus rex has been uncovered in northeast China.

Raptorex kriegsteini would have been about 100 times smaller than its tyrannosaur descendents, weighing in at only about 150 pounds and about eight or nine feet in length; a punk compared to the forty-foot, six-ton T. rex.

But the new discovery possesses the same puny forelimbs, massive legs, oversized head, crushing jaws, and large olfactory bulb as the T. rex. Only much smaller. In fact, the entire body length of Raptorex would be less than twice that of just the skull of a Tyrannosaurus rex (9 feet verses 5 feet).

The fossil was found in Mongolia and sold on the open market. The buyer contacted paleontologist Paul Sereno, who agreed to describe it, but only on condition the buyer agreed to turn it over to science. The Sereno et al. study appears in Science Express, the online edition of the journal Science.

"Many of these traits have never been seen in anything but the big brutes," Sereno said. "That's what's so surprising about the whole thing, from tooth to limbs to even the space for the brain, we see things we used to think were just exclusive to the big tyrannosaurids in the late Cretaceous. But there they are."

Despite its reduced size the new dinosaur would still have been a formidable predator to its prey. But the find means the blueprint for the famous Tyrannosaurus rex goes way back in the family line, something not expected.

Learn more from Paul Sereno himself in this video from the University of Chicago.

Raptorex (which means “king of thieves) lived in the Early Cretaceous about 125 million years ago, and several tens of millions years before its famous descendent italicizedT. rex roamed the Earth in the waning days of the dinosaurs.

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