History Files
 

 

Mesozoic World

Feathered Dinosaur

Dr David Whitehouse, 25 April 2001

A fossil dinosaur was unearthed which was wrapped from head to tail in feathers. It would add to the debate about birds being descended from dinosaurs, and suggested that the evolution of feathers predated the development of flight.

The 130 million-year-old Dromaeosaur specimen provided the best evidence yet that some dinosaurs developed primitive feathers - not for flight but probably to keep warm. The creature was a small predator which was closely related to the Velociraptor (star of the first Jurassic Park film).

Like Velociraptor, they had a sickle-like claw on the middle toe, sharp teeth, and a bone structure similar to that of modern birds.

Barbed features

The fossil was unearthed in spring 2000 by farmers digging in north-eastern China's Liaoning province. It was entombed in two slabs of fine-grained rock.

When the slabs were separated the farmers saw a fossil which resembled a large duck with a long tail and an oversized head. The fine-grained rock allowed minute details to be preserved which showed that the creature's head and tail were covered with downy fibres, while other parts of the body seemed to have tufts or sprays of filaments resembling primitive feathers. The arms also seemed to be adorned with branched structures which were similar to the barbs of modern bird feathers.

Fierce arguments

Dr Mark Norell of the American Museum of Natural History, New York, stated that the fossil radically modified the way scientists would see these extinct animals. It showed that advanced theropod (two-legged) dinosaurs may have looked more like weird birds than giant lizards.

Several new species of dinosaur with feather-like structures were found in the Liaoning fossil beds since the first, Sinosauropteryx, was discovered in 1995. In most cases, the fossils were incomplete, making it unclear how the feather-like structures related to the animal's body. Most experts of the time believed that modern birds had evolved from dinosaurs (a theory which itself would be subject to later development), and they were citing the Liaoning fossils as evidence.

However, critics of the theory were arguing that the feather-like structures were not the remains of primitive feathers, or that the specimens were instead mixed-up fossils of early birds and dinosaurs.

  Dinosaurs may have looked more like weird birds than giant lizards

Doctor Mark Norell  

Body temperature

It was hoped that this new find could help to resolve the debate. It contained details so fine that scientists would be able to see how the primitive feathers were attached to the dinosaur's body.

Ji Qiang of the Chinese Academy of Geological Sciences, Beijing, was happy to point out that this was the specimen that scientists had been waiting for. It made it indisputable that a body covering which was similar to feathers was present in non-avian (flightless) dinosaurs.

The Dromaeosaur is more primitive than birds, suggesting that feathers developed before flight. Scientists thought that the feathers may have evolved as insulation to keep the animal warm. Dr Norell suggested that it was conceivable that smaller dinosaurs like this one and even the young of larger species like Tyrannosaurus rex may have needed feather-like body coverings to maintain their body temperature.

The Dromaeosaur fossil was loaned out by China in 2001, being displayed for the first time at the American Museum of Natural History. While in the United States, it also travelled to Texas for imaging by a CAT scanner, which provided a three dimensional view of the skeleton.

 

 

     
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