Posted by: Craig Woolheater on June 27th, 2007
HONG KONG/BEIJING (Reuters) – China has uncovered the skeletal remains of a gigantic, surprisingly bird-like dinosaur, which has been classed as a new species.
Eight meters (26 ft) long and standing at twice the height of a man at the shoulder, the fossil of the feathered but flightless Gigantoraptor erlianensis was found in the Erlian basin in Inner Mongolia, researchers wrote in the latest issue of Nature.
The researchers said the dinosaur, discovered in April 2005, weighed about 1.4 tonnes and lived some 85 million years ago.
According to lines of arrested growth detected on its bones, it died as a young adult in its 11th year of life.
What was particularly surprising was its sheer size and weight because most theories point to carnivorous dinosaurs getting smaller as they got more bird-like.
“It had no teeth and had a beak. Its forelimbs were very long and we believe it had feathers,” Xu Xing at the Chinese Academy of Sciences’ Institute of Vertebrate Paleontology & Paleonanthropology said in a telephone interview.
Through analyzing its skeleton, the researchers believe the Gigantoraptor shared the same ancestor and belonged to the same family as the Oviraptor.
With a beak and feathers, the Oviraptor is also bird-like and flightless, but weighed a mere 1 to 2 kg, Xu said.
Other similar feathered dinosaurs rarely weighed over 40 kg, which means the Gigantoraptor was about 35 times heavier.
The largest known feathered animal before the Chinese discovery was the half-tonne Stirton’s Thunder Bird, which lived in Australia more than six million years ago.
“It’s a giant dinosaur that looked very much like a bird … whereas from what we have known before, bird-like dinosaurs were very, very small. Large dinosaurs are usually not bird-like. So this Gigantoraptor was an exception,” Xu said.
If the Gigantoraptor had lived to a full-sized adult, it would have been a lot larger, but Xu could not estimate what that would have been.
However, the researchers believe it had an accelerated growth rate that was faster than the large North American tyrannosaurs.
The scientists had originally thought they had found tyrannosaur bones, as they were so large.
“It was a very surprising discovery, not at all what we expected,” Xu said later at a news conference in Beijing. “So we spent a lot of time investigating the fossils which is why it took us so long to announce the results.”
The scientists showed off two huge fossilized bones from the animal, and a model of its beaked head.
Its feathers were likely for show and for keeping its eggs warm, Xu added.
“We think it’s the largest feathered animal ever to have been discovered,” he said.
It had both herbivorous features — a small head and long neck — but also carnivorous ones — sharp claws for tearing meat — and could likely run fast on its long, powerful legs, the professor said.
“Of course, there’s no way of knowing for sure,” he added.
Its site of discovery, near Erenhot on the Chinese-Mongolian border, is known for fossils and calls itself “dinosaur town.”
The city of just 100,000 is hoping to leverage this fame to attract tourists, said its Communist Party chief Zhang Guohua, and will spend more than 100 million yuan ($13.11 million) on a new dinosaur fossil museum this year.Tan Ee Lyn and Ben Blanchard