Friday, January 26, 2007

New Dinosaur Discovered: T. Rex Cousin Had Feathers

Very small, previous cousin of rex of Tyrannosaurus at least amused a partial layer of the pens of hairlike, disclosed scientists today. The persecuted prey dinosaurio and vagado the forests of lakeside of the province of Liaoning in northern China makes about 130 million years, the investigators said. Although it is predicted by several paleontlogos, the marks of the discovery the first time that the structures of featherlike have been observed directly in tyrannosaurid. Tyrannosaurids is dinosaurios predominant great with forelimbs short that vagaron the Earth does 130 to 65 million years.

"It is the thing class that we hoped, but we thought that it can be that we never find a fossil that would demonstrate it justifiable," we said the Norell mark, that Co-she was author of a paper that describes the new species. The study appears tomorrow in the nature of the newspaper of science. Norell, a guardian and the chair of the division of paleontology in the American museum of New York of natural history, said the theories that the dinosaurios were birdlike, the creatures of hot blood of the aids of the discovery that developed pens to remain hot-not to fly.

The investigators named paradoxus new of Dilong of the species of dinosaurio. Dilong derives from the words of the official held in low esteem that mean the "emperor" and the "dragoon." Paradoxus refers the found unusual pens in 5 carnivorous the foot-long one (1.5-to put-long). The investigation was partly supported by a concession of the committee of the national geographic society on the investigation and the exploration. Thomas Holtz, vertebrate paleontologo in the university of Maryland in park of the university, was between the group of early paleontologos to predict that tyrannosaurids had pens. The scientist, who was not implied in the study, said that they move it in the last finding.

"There are many of attention given to the surprises in paleontology," he said. "But there is a side to him where we hoped to be scientists, and the part of science bases on the predictions that are based on the best present evidence. Aid to see the casserole of the predictions towards outside with discoveries." The predictions Holtz and other paleontologos have done are based on the skeletal data that suggest them tyrannosaurids had a more recent common ancestor with the birds that Sinosauropteryx, dinosaurio emplumado known more primitive. Sinosauropteryx lived 120 ago to 150 million years. Holtz observed that, if the early pens of Sinosauropteryx and the pens of birds and other emplumados dinosaurios are all the expressions of he himself evolutionary change, "then we must deduce that tyrannosaurids also [had certain expression of he himself characteristic the pens]."

"To deduce of another way he would be invoking an evolutionary change for which we did not have any evidence," he said. Xu Xing of the institute of vertebrate paleontology and Paleoanthropology in Beijing, China, is the author of the lead of the new paper. It said his discovery is significant because he spills the light in the evolution of tyrannosaurids, that includes rex giant of the carnivorous T. Tyrannosaurids belongs to a ampler group, diverse of dinosaurios known like coelurosaurs. Most of the paleontologos they think that this group gave rise to birds. How it happened east evolutionary change is complex, Xu this. Tyrannosaurids great as rex of the T. were covered according to inquires in scales instead of the pens, suggesting they were related distant to the birds.

"With this new finding, we can see a perfect evolutionary transition of coelurosaurians typical tyrannosaurids great extremely specialized and to clarify a number of questions," Xu this. Particularly, the head of the new specimen shares many characteristics with tyrannosaurids advanced, said Xu, whereas its body is of a form coelursaurian more primitive, more nonspecific. The Hans-Dieter demands, the director of the associate for the investigation and the collections in the national museum of the institution of Smithsonain of natural history in Washington, C.C., agree. "New tyrannosaur small definitively demonstrates a primitive interesting mosaic of and characteristics derived; its skull is already the one of another one, tyrannosaurs rather last than the rest of its skeleton," said demand, that it is a member of the committee of the national geographic society for the investigation and the exploration.

The characteristic outposts of the skull of tyrannosaurid observed in Dilong include teeth and a single nasal bone. (Dinosaurios more primitive offered a pair of nasal bones.) Pero desemejante of tyrannosaurids more advanced, Dilong had relatively long forearms with three fingers, the report of the investigators. According to Holtz, the university of the paleontelogo of Maryland, the combination of a head outpost of tyrannosaurid with a body generalized of coelurosaur is constant within paleontology. "For example, the contemporary ceratopsian primitive of Psittacosaurus-a, and perhaps the prey, of Dilong-demonstrates a head with the initial changes towards the specializations of feeding of dinosaurios of last horns. The small pieces [of] their body are a body of herbivore generic," he said.


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