'Tiny' new T-Rex ancestor found in China (w/ Video)

Sep 17, 2009
Weighing as little as 1/100th that of its descendant T. rex, 125-million year old Raptorex shows off the distinctive body plan of this most dominant line of predatory dinosaurs. This is based on a fossil skeleton discovered in Inner Mongolia, China. Credit: Drawing by Todd Marshall

(PhysOrg.com) -- A 9-foot dinosaur from northeastern China had evolved all the hallmark anatomical features of Tyrannosaurus rex at least 125 million years ago. University of Chicago paleontologist Paul Sereno and five co-authors describe the newly discovered dinosaur in the Sept. 17 Science Express, advanced online edition of the journal Science.

Raptorex shows that tyrannosaur design evolved at "punk size," said Sereno, a National Geographic Explorer-in-Residence, "basically our bodyweight. And that's pretty staggering, because 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."

Raptorex displays all the hallmarks of its famous descendant, , including a large head compared to its torso, tiny arms and lanky feet well-suited for running. The Raptorex brain cast also displayed enlarged olfactory bulbs—as in T. rex—indicating a highly developed sense of smell.

This video is not supported by your browser at this time.

"It's really stolen from tyrannosaurids all the fire of the group," Sereno said. All that Raptorex left for its descendants is "a suite of detailed features largely related to getting bigger."

At only 9 feet in length, Raptorex already had the powerful jaws, puny arms, and quick legs of its much larger and more famous descendants. Credit: Drawing by Todd Marshall

Sereno marvels at the scalability of the tyrannosaur body type, which when sized up 90 million years ago completely dominated the predatory eco-niche in both Asia and North America until the great extinction 65 million years ago at the end of the .

"On other continents like Africa, you have as many as three large predators living in the same areas that split among them the job of eating meat," he said. But in Africa, the allosaurs never went extinct, as they did in North America, possibly presenting an evolutionary opportunity for Raptorex. "We have no evidence that it was a competitive takeover," said Sereno, "because we have never found large tyrannosaurs and allosaurs together."

Henry Kriegstein, a private collector, brought the nearly complete Raptorex skeleton to Sereno's attention after buying it from a vendor. After Sereno and colleagues finish amore detailed study of Raptorex, it will be returned to a museum in Inner Mongolia, the place where the fossil was illicitly excavated.

More information: Paul C. Sereno, Lin Tan, Stephen L. Brusatte, Henry J. Kriegstein, Xijin Zhao and Karen Cloward, "Tyrannosaurid Skeletal Design First Evolved at Small Body Size," early online edition of Science, Sept. 17, 2009.

Source: University of Chicago (news : web)

Explore further: Undergrad researcher unearths dino discovery

add to favorites email to friend print save as pdf

Related Stories

Dinosaur from Sahara ate like a 'Mesozoic cow'

Nov 15, 2007

A 110 million-year-old dinosaur that had a mouth that worked like a vacuum cleaner, hundreds of tiny teeth and nearly translucent skull bones will be unveiled Thursday, Nov. 15, at the National Geographic ...

Young dinosaurs roamed together, died together (w/Video)

Mar 16, 2009

A herd of young birdlike dinosaurs met their death on the muddy margins of a lake some 90 million years ago, according to a team of Chinese and American paleontologists that excavated the site in the Gobi ...

T.rex 'followed its nose' while hunting

Oct 29, 2008

Although we know quite a bit about the lifestyle of dinosaur; where they lived, what they ate, how they walked, not much was known about their sense of smell, until now.

Recommended for you

Dinosaur footprints set for public display in Utah

9 hours ago

A dry wash full of 112-million-year-old dinosaur tracks that include an ankylosaurus, dromaeosaurus and a menacing ancestor of the Tyrannosaurus rex, is set to open to the public this fall in Utah.

Fossil arthropod went on the hunt for its prey

19 hours ago

A new species of carnivorous crustacean has been identified, which roamed the seas 435 million years ago, grasping its prey with spiny limbs before devouring it. The fossil is described and details of its lifestyle are published ...

User comments : 2

Adjust slider to filter visible comments by rank

Display comments: newest first

otto1923
Sep 17, 2009
This comment has been removed by a moderator.
otto1923
Sep 17, 2009
This comment has been removed by a moderator.
RayCherry
4.5 / 5 (2) Sep 18, 2009
... it will be returned to a museum in Inner Mongolia, the place where the fossil was illicitly excavated"


Not a small detail.

This "Indiana Jones" form of science treasure hunting has to stop. It has caused enough trouble in the past and modern methods can be used to avoid such mistakes.

"Fencing" national property has to be made financially unprofitable, and "classification/authentication of materials of dubious origins" by credible universities and/or other authorities should become "bad science".

This "socially/academically acceptable" behaviour has real long-term consequences on international relations and now that the technology permits tracking of materials and transactions this "wink-wink" backdoor evidence gathering by the "institutions of our peers" should come to an end.

Unity of the political, social and academic systems of our world is technologically feasible and sociologically fundamental ... if we are to control resources and explore other worlds.
jerryd
1 / 5 (1) Sep 18, 2009

Why does it have to stop? n It's not like there is any lack of fossils. Better to make it legal, regulated so finds can be studied, then sold.

If we wait for academics we will never find much.