Brian Choo
An artist’s impression of
Yutyrannus huali, a giant, previously unrecognized dinosaur. The name of
the species means “beautiful feathered tyrant.”
By JOHN NOBLE WILFORD
Published: April 4, 2012
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 animal’s 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 at the American Museum of
Natural History in Manhattan, who had no part in the research, said the
findings were significant because they swept aside a longstanding
argument that perhaps dinosaurs had feathers only when they were small
and shed them as they grew.
Corwin Sullivan, a Canadian paleontologist affiliated with the Beijing
institute 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.”
The researchers suggested that the climate might have been cooler when
this feathered giant lived than it was when T. rex roamed in the late
Cretaceous period. Not necessarily, said Dr. Norell, who pointed out
that large, hairy mammals like giraffes and wildebeest, perhaps
analogous to feathered dinosaurs, live today in hot latitudes.
Another possible explanation, offered by the authors of the journal
article, is that the feathers were not widely distributed over the
dinosaurs’ bodies, and so their function as display plumage cannot be
ruled out. Yet the researchers noted several times that the feather
covering was extensive and “densely packed,” resembling some recent
discoveries of fossil birds “that undoubtedly had plumage covering most
of the body.”
“This is a great time to be a dinosaur paleontologist,” said Dr. Norell,
whose research concentrates on fossils from China and the Gobi Desert
of Mongolia. “The feathered dinosaurs show how the whole conception of
dinosaurs has really changed in the last 15 years.”
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