Scientists discover 2 new dinosaur species

April 22, 2009 By James Janega

Researchers from Field Museum in Chicago have helped discover two new dinosaur species in China's Gobi Desert: a 5-foot-tall forebear of Tyrannosaurus rex and a half-ton beaked dinosaur reminiscent of a giant ostrich.

The findings, reported online this week in the scientific journal , follow two summers of collaborative research between U.S. and Chinese scientists who found the new species and several others in rocky strata in the southern Gobi.

Both lived about 110 million years ago, researchers said.

One of the species, Xiongguanlong baimoensis (shong-GWAN-long by-mo-EN-sis), suggests how tyrannosaurs evolved into eating machines that later terrorized the Cretaceous Period.

T. rex and Albertosaurus are the largest, best known and most recent tyrannosaurs known to stalk the Earth. In the last decade, fossils of the species' earliest known and much smaller forebears were unearthed in China and England.

The mid-weight Xiongguanlong appears in the 50-million-year gap between those groups, its discoverers say. While the species was not yet the prehistoric terror its descendants would become, it marks the earliest appearance of key traits such as broader skull attachments for massive jaw muscles and thicker vertebrae to support larger heads.

"It gives us a nice window on a chapter of tyrannosaur evolution that we didn't have," said Peter Makovicky, curator of dinosaurs at the Field.

The second species, Beishanlong grandis (bay-SHAN-long gran-DIS), is one of the biggest ornithomimosaurs, or ostrich-shaped dinosaurs, yet found. Though researchers believe the creature perished in its 14th year of life, it already weighed 1,400 pounds, with 6-inch claws on its hands and powerful forelimbs for digging and raking the ground.

"Just finding something that big -- I've been doing it for a while, but there's still that 10-year-old boy inside of me," Makovicky said.

This team also found evidence of several other dinosaur species, as well as a noteworthy pattern of fossil distribution: Horned and sickle-clawed dinosaurs dominated in reddish rocks deposited in dry conditions, while tyrannosaurs, ornithomimosaurs and duck-billed dinosaurs were found in rocks formed in wetter environments.

"That's a pretty exciting bigger-picture look at how animals might have evolved with environments in which they occurred," Makovicky said.

___

(c) 2009, Chicago Tribune.
Visit the Chicago Tribune on the Internet at www.chicagotribune.com/
Distributed by McClatchy-Tribune Information Services.

Explore further: Edmonton city site was dinosaur dining room

Related Stories

Edmonton city site was dinosaur dining room

June 29, 2007

A dinosaur bone bed in southwest Edmonton that served as a feeding area for the direct ancestor of Tyrannosaurus rex has revealed that two dinosaurs, thought to have lived in different eras, actually lived at the same time.

Recommended for you

Early human diet explains our eating habits

August 31, 2015

Much attention is being given to what people ate in the distant past as a guide to what we should eat today. Advocates of the claimed palaeodiet recommend that we should avoid carbohydrates and load our plates with red meat ...

Just how good (or bad) is the fossil record of dinosaurs?

August 28, 2015

Everyone is excited by discoveries of new dinosaurs – or indeed any new fossil species. But a key question for palaeontologists is 'just how good is the fossil record?' Do we know fifty per cent of the species of dinosaurs ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.