The dinosaur with the longest neck

A sauropod from the Late Jurassic epoch had the longest neck of any dinosaur on record. An analysis of its vertebrae indicates that it stretched 15.1 metres.

Mamenchisaurus sinocanadorum was discovered in Xinjiang province in China in 1987, but only a few bones, including some of its vertebrae and a rib, were preserved. It was named officially in 1993, but the animal’s size and scale haven’t been fully established until now.

The original paper reporting the discovery of the sauropod didn’t provide a neck length, but implied it would be between 10 and 11 metres. To provide a more accurate estimate of the neck length, Andrew Moore and his colleagues at Stony Brook University in New York looked at the relative proportions of the remaining vertebrae from M. sinocanadorum and compared them with related dinosaurs for which we have fossils of the entire neck. At 15.1 metres, its neck would have been six times longer than a giraffe’s.

Another question Moore and his colleagues tried to tackle was how the sauropod could have supported the weight of such a long neck. By putting the remaining vertebrae in a computed tomography (CT) scanner, they realised that between 69 and 77 per cent of the vertebrae was empty space.

“Having such a long neck was made possible, we think, not only by making the bones lightweight by replacing marrow with air, but also potentially limiting the mobility of the neck so it’s more amenable to being pumped full of air,” says Moore. Cervical ribs that interlink below the neck also helped support the neck, the researchers believe.

This story is based on an article in New Scientist. The original research was published in Journal of Systematic Palaeontology.

Bill Gray