Tiny tyrannosaur had all the trappings of T. rex

Millions of years before the first tremendous Tyrannosaurus rex began terrorizing fellow animals, Raptorex kriegsteini showed all of the characteristic tyrannosaur features—in miniature.

PAUL SERENO

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Millions of years before the first tremendous Tyrannosaurus rex began terrorizing fellow animals, Raptorex kriegsteini showed all of the characteristic tyrannosaur features—in miniature.

Weighing in at about 1 percent of the latter theropod's mass, Raptorex hunted with the same bipedal gait, stubby arms and keen sense of smell as its daunting cousin. Despite being a fairly diminutive dino, it still was nearly three meters long, weighed about 80 kilograms and would have been a fearsome match for a midsize mammal like a human.

"There's no other example that I can think of where an animal has been so finely designed at about 100th the size that it would eventually become," Paul Sereno, a paleontologist at the University of Chicago, said in a prepared statement. He and five other co-authors describe the new carnivore in a paper in Science today.

In this image, the Raptorex's skull is shown to be just a fraction the size of a full-grown T. rex skull.

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