Thu, May 28, 2009 - Page 6 News List

Researchers say dinosaurs held heads up, not forward

THE GUARDIAN , LONDON

British fossil experts sparked turmoil in the normally staid world of paleontology yesterday as they challenged a familiar view of dinosaurs.

The controversy goes to the heart of our perception of the largest of the dinosaurs, the sauropods, which became widespread 150 million years ago in the late Jurassic period.

A fresh analysis of animal bones indicates that the beasts did not stick their necks out in front of them as is often depicted, but held their heads high on majestic, curving, swan-like necks.

The claim overturns the popular impression of the lumbering creatures given by museum exhibits and TV series such as the BBC’s Walking with Dinosaurs.

The sauropods include many of the best known prehistoric beasts, such as diplodocus and apatosaurus, the dinosaur formerly known as brontosaurus.

“Unless sauropods carried their heads and necks differently from every living vertebrate, we have to assume that the base of their neck was curved strongly upwards,” said Mike Taylor of Portsmouth University in England, who led the study. “In some sauropods, this would have meant a graceful, swan-like S-curve to the neck, and a look quite different from the recreations we are used to seeing today.”

In their study, Taylor and his team examined the natural neck posture of a wide range of land vertebrates, such as cats, rabbits, turtles and crocodiles.

They found that almost all hold their necks in an upright, S-shaped curve, even though analysis of the bones alone would suggest the neck should stick out horizontally. His report appears in the journal Acta Paleontologica Polonica.

The idea that sauropods held their necks upright is not new. Until the 1950s, most dinosaur experts considered this to be their natural posture.

That view changed when scientists suggested that an upright neck would raise the animals’ blood pressure catastrophically.

But Taylor said the estimates of blood pressure were based on extrapolations from smaller animals, which he doesn’t believe are valid for larger creatures.

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