Skip to comments.Fossil Find Challenges Theories on T. Rex
Posted on 09/18/2009 7:36:50 AM PDT by SeekAndFind
Paleontologists said Thursday that they had discovered what amounted to a miniature prototype of Tyrannosaurus rex, complete with the oversize head, powerful jaws, long legs and, as every schoolchild knows, puny arms that were hallmarks of the king of the dinosaurs.
But this scaled-down version, which was about nine feet long and weighed only 150 pounds, lived 125 million years ago, about 35 million years before giant Tyrannosaurs roamed the earth. So the discovery calls into question theories about the evolution of T. rex, which was about five times longer and almost 100 times heavier.
The thought was these signature Tyrannosaur features evolved as a consequence of large body size, Stephen L. Brusatte of the American Museum of National History, an author of a paper describing the dinosaur published online by the journal Science, said at a news conference. They needed to modify their entire skeleton so they could function as a predator at such colossal size.
The new dinosaur, named Raptorex kriegsteini, really throws a wrench into this observed pattern, Mr. Brusatte said.
The nearly complete fossil was found in northeastern China and bought by a collector, Henry J. Kriegstein, who alerted Paul C. Sereno, a paleontologist at the University of Chicago and lead author of the paper. The fossil, which was illicitly excavated, will be returned to a museum in China.
Dr. Sereno said the fossil was that of a young adult, about 5 or 6 years old and near the end of its growth period. Besides the oversized head, jaws and legs, it had long shinbones and long, compressed feet that helped it run fast after smaller dinosaurs and other prey. We see this all, to our great surprise, in an animal that is basically the body weight of a human, Dr. Sereno said.
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That seems to happen frequently. But they don't seem to mind.
Doesn't look like T-Rex to me.
Raptors come in all different sizes now, from falcons to eagles. It's possible the same avian characteristics we see in the larger dinos was similar in pattern to various sizes as needed for the environment.
For as much as we know, there is a whole lot more yet to discover.
I agree. Head’s too small in proportion to the body [unless it’s the camera angle.
It does to me. It looks a bit out of proportion because of the longer backbone and legs in relation to the skull, but even then, compare that skull to other raptors. This thing had some serious jaw muscles to need a head that big, and the front limbs are seriously atrophied. Nice find.
Of course this has to be evolution and not a T-rex that was an infant.
Something doesn't sound right here. I'm a little over 6 feet and weigh around 200 pounds.
You don’t have a tail, at least that’s my working assumption.
Really? It looks fairly prototypical to me of what is characterized as a T-Rex.
Of course, it could just be a ‘beta’ test version, or one of those demo’s they put out at a car show and never make.
Exactly. No tail, but I’m still heavier