Feathered dinosaur fossil may provide clues to how dinos evolved into modern birds

January 17th, 2009 - 2:19 pm ICT by ANI  

National Geographic

Washington, Jan 17 (ANI): Scientists have uncovered the fossil of a primitive feathered dinosaur in China, which is helping them create a better model of how dinosaurs evolved into modern birds.

According to a report in National Geographic News, the winged dinosaur is still in the process of being dated, and might have lived toward the end of the Jurassic period, which lasted from 208 to 144 million years ago.

In many ways, it is more basal, or primitive, than Archaeopteryx, said paleontologist Xu Xing at Beijings Institute of Vertebrate Paleontology and Paleoanthropology.

Archaeopteryx, the earliest known bird, lived 150 million years ago.

The protobird is very close to the point of divergence at which a new branch of winged dinosaurs first took flight, said Xu.

The new species, called Anchiornis huxleyi, was discovered in the ashes of volcanoes that were active during the Jurassic and Cretaceous (144 to 65 million years ago) periods in what is now northeastern China.

Anchiornis, which is Greek for close to bird, measured just 13 inches (34 centimeters) from head to tail and weighed about 4 ounces (110 grams).

The dinosaurs body and forelimbs were covered with feathers, and it might have had some aerial capability, Xu said. Anchiornis is one of the smallest theropod dinosaurs ever uncovered, he added.

The fossil provides new clues about how feathers, wings, and flight progressively appeared among theropods, along with evidence that certain types of feathered dinosaurs decreased in stature even as their forelimbs became elongated.

The compact structure of Anchiornis reinforces the deduction that small size evolved early in the history of birds, Xu explained.

Anchiornis exhibits some wrist features indicative of high mobility, presaging the wing-folding mechanisms seen in more derived birds, he said.

The wrist is a big part of the formation of wings, and pivotal to flight. During flight, steering and flapping greatly depend on the wrist, Xu added.

Despite this protobirds relatively advanced feathers and wrist, it is unclear if Anchiornis could actually engage in powered flight.

According to Mark Norell, chairman and curator of the division of paleontology at the American Museum of Natural History in New York, Behavior and biomechanics are very difficult to determine solely from the fossil record, and perhaps flight is impossible to determine. (ANI)

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