for National Geographic News
A tiny, earlier cousin of Tyrannosaurus rex sported at least a partial coat of hairlike feathers, scientists reported today. The dinosaur chased prey and roamed the lakeside forests of Liaoning Province in northern China some 130 million years ago, researchers said. (See pictures of the new dinosaur.)
Although predicted by several paleontologists, the discovery marks the first time featherlike structures have been directly observed on a tyrannosaurid. Tyrannosaurids are predominantly large dinosaurs with short forelimbs that roamed Earth 130 to 65 million years ago.
"It's the kind of thing we expected, but we thought we might never find a fossil that would justifiably show it," said Mark Norell, who co-authored a paper that describes the new species. The study appears tomorrow in the science journal Nature.
Norell, a curator and chair of the division of paleontology at New York's American Museum of Natural History, said the discovery supports theories that dinosaurs were birdlike, warm-blooded creatures that evolved feathers to stay warmnot to fly.
Researchers named the new dinosaur species Dilong paradoxus. Dilong derives from Mandarin words meaning "emperor" and "dragon." Paradoxus refers to the unusual feathers found on the 5-foot-long (1.5-meter-long) carnivore.
The research was supported in part by a grant from the National Geographic Society's Committee on Research and Exploration.
Thomas Holtz, a vertebrate paleontologist at the University of Maryland in College Park, was among the group of paleontologists to predict that early tyrannosaurids had feathers. The scientist, who was not involved in the study, said he is thrilled at the latest find.
"There is a lot of attention given to surprises in paleontology," he said. "But there is a side to it where we hope to be scientists, and part of science is based on predictions that are based on the best evidence at hand. It helps to see predictions pan out with discoveries."
The predictions Holtz and other paleontologists have made are based on skeletal data that suggest tyrannosaurids had a more recent common ancestor with birds than did Sinosauropteryx, the most primitive known feathered dinosaur. Sinosauropteryx lived 120 to 150 million years ago.
Holtz noted that, if the early feathers of Sinosauropteryx and the feathers of birds and other feathered dinosaurs are all expressions of the same evolutionary change, "then we have to infer that tyrannosaurids also had some expression of the same trait [feathers]."
"To infer otherwise would be invoking an evolutionary change for which we had no evidence," he said.
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