BioEd Online

Talk about sticking your neck out: palaeontologists working in Mongolia have discovered a dinosaur that was far ahead of its peers. The creature had one of the longest necks of all time, measuring a staggering eight metres.

Relative to body size, the creature is a contender for the most impressive neck ever, say its discoverers. Although smaller overall than the famous Diplodocus, the new dinosaur is even more outlandishly proportioned - more than a third of its body length was in front of its shoulders.

Fossil-hunters dug up bones from the new species, called Erketu ellisoni, at Bor Guvé in the Gobi Desert in 2002. The haul consisted of several leg bones, part of a breastbone, and six vertebrae, each twice the size of a loaf of bread.

The full skeleton probably included 14 or 15 of these huge bones, strung together to make a prodigiously long neck, says Daniel Ksepka of New York's American Museum of Natural History, who describes the fossil in the journal AMNH Novitates¹.

Overstretched

The bones could scarcely be more different from the vertically positioned vertebrae that hold up our own heads, Ksepka says. "Ours are like a little stack of doughnuts," he says, whereas E. ellisoni's are very elongated.

And far from having its head in the clouds, the creature was probably pretty level-headed. "A lot of people suppose that long necks would have been held upright," says Ksepka. "But theory suggests that the neutral pose was almost parallel to the ground, so as to cover a wide grazing area rather than the highest trees."

The huge appendage must have been immensely heavy. But E. ellisoni had a neat trick up its sleeve. As well as containing air cavities to reduce density, the larger vertebrae also feature a large V-shaped notch. This looks as if it housed a ligament that would have added rigidity. "It's almost like having a bungee cord holding the neck up," Ksepka explains. "You don't want to be using the muscles."

Lumbering giants

The giant plant-eater is closely related to a group called, appropriately enough, the titanosaurs, says Ksepka's colleague Mark Norell, who has also studied the specimen. This group is part of a larger clan called the sauropods, which features Diplodocus and other lumbering dinosaurs.

Titanosaur fossils have now turned up on just about every continent on the globe. The group was very long-lived, surviving throughout the Cretaceous period, which ended with the demise of almost all dinosaurs 65 million years ago. But few were the proud possessors of bodies as freakish as E. ellisoni, says Norell: "On the weirdo index, this is pretty weird."

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