for National Geographic News
The earliest in a line of dinosaurs that gave rise to Tyrannosaurus rex has been discovered in China.
Scientists say the 160-million-year-old animal, which had an elaborate head crest and possibly bore simple feathers, is the oldest known tyrannosaura group of swift, flesh-eating dinos that culminated in T. rex some 90 million years later.
Two specimens of the previously unknown dinosaur have been found in the fossil-rich badlands of Xinjiang province in northwest China (map).
The primitive tyrannosaurs were discovered together. They appeared to have become fatally trapped in a prehistoric mud pit, according to Xing Xu, professor at the Institute of Vertebrate Paleontology and Paleoanthropology in Beijing, China. The carnivores were possibly lured to their deaths by other mud-stricken animals, which also left behind fossil remains.
"This is an unbelievable discovery with tremendous new information on the evolution of the tyrannosaurs," Xu said.
Xu and fellow dino experts describe the new species, named Guanlong wucaii, in tomorrow's issue of the journal Nature.
The National Geographic Society supported fieldwork that uncovered the new dinosaur.
The diminutive dinosaur stood 3.6 feet (1.1 meters) tall and measured 9.8 feet (3 meters) long. But researchers say the most striking thing about Guanlong (which means "crowned dragon" in Chinese) was its large, complex head crest.
Similar in appearance to ornamental features seen in birds like cassowaries and hornbills, the crest may have been used for display, the study team suggests.
About as thick as a tortilla and 2.5 inches (6.4 centimeters) high, the crest certainly wouldn't have been much use as a weapon, said study co-author James M. Clark, biology professor at The George Washington University in Washington, D.C.
"It seems paradoxical that a presumably predatory dinosaur like Guanlong would possess such a delicate cranial crest," he said.
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