LONDON - Ever since palaeontologists pieced together the many bones of lumbering sauropods they have argued about how these largest of dinosaurs would have held their immensely long necks.

Now the debate has taken another turn with a study suggesting that museums have got it wrong when they depict sauropods extending their long necks out in front of their huge bodies.

New research suggests that sauropods held their necks in an upright posture, as swans or giraffes do, rather than in the near-horizontal position depicted by the famous diplodocus in the Great Hall of the Natural History Museum in London.

"We have now discovered that the way the dinosaur is depicted in the iconic model at the Natural History Museum is not how it would have habitually held its neck," said Dr Mike Taylor, of Portsmouth University.

After studying living animals and comparing their necks to those of the sauropods, Taylor and his colleagues concluded that the dinosaurs could have held their heads high.

"We can't just study fossil bones," he said. "Dinosaurs were living animals and ... We need to look at animals that are alive today. 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."

But Paul Barrett, an expert at the Natural History Museum, dismissed the suggestion that exhibits would have to be changed. He said the upright necks theory was not a new idea.