Fossils discovered in northeastern China of a giant,previously unrecognized dinosaur show that it is the largest known feathered animal,living or extinct,scientists report.
Although several species of dinosaurs with feathers have already been uncovered in the rich fossil beds of Liaoning Province,the three largely complete 125-million-year-old specimens are by far the largest. The adult was at least 30 feet long and weighed a ton and a half,about 40 times the heft of Beipiaosaurus,the largest previously known feathered dinosaur. The two juveniles were a mere half ton each.
The new species was a distant relative of Tyrannosaurus rex,the mighty predator that lived 60 million years later,at the end of the dinosaur era. The scaly T rex apparently did not go in for feathers.
In an article in the journal Nature,published online Wednesday,Chinese and Canadian paleontologists said the discovery provided the first direct evidence for the presence of extensively feathered gigantic dinosaurs and offered new insights into early feather evolution.
Xing Xu of the Institute of Vertebrate Paleontology and Paleoanthropology in Beijing,who was the lead author of the paper,said in a statement that it was possible that feathers were much more widespread,at least among meat-eating dinosaurs,than most scientists would have guessed even a few years ago.
Dr Xu said the feathers were simple filaments,more like the fuzzy down of a modern baby chick than the stiff plumes of an adult bird. Such insubstantial feathers,not to mention the animals huge size,would have made flight impossible. The feathers most important function was probably as insulation.
The species has been named Yutyrannus huali,which means beautiful feathered tyrant in a combination of Latin and Mandarin.
Mark A Norell,a curator of paleontology,said the findings were significant because they swept aside the argument that perhaps dinosaurs had feathers only when they were small.
Corwin Sullivan,a Canadian paleontologist and an author of the report,noted that the idea of primitive feathers for insulation was not new. However,large-bodied animals typically can retain heat quite easily,and actually have more of a potential problem with overheating, Dr. Sullivan said. That makes Yutyrannus,which is large and downright shaggy,a bit of a surprise.