"The vertebrae aren't solid bone but honeycombed with chambers which were probably filled with air," Ksepka said.
"This was definitely helping to reduce the overall weight of the animal, particularly the neck," he said.
"You don't want a lot of weight up frontthat would off-balance the animal."
"This honeycomb structure is an advanced feature which you see pretty high up in the sauropod evolutionary tree," Ksepka added.
The researchers also report that the tops of these neck bones were split into two parallel tracks, likely allowing room for a ligament that helped the dinosaur lift its neck.
"Research that's been done lately indicates that other, similar sauropods probably held their necks parallel to the ground," Ksepka said.
"We think this animal had a similar posture," he added.
"It may have had this long neck to easily graze over a large area rather than to reach to the very tip of a tree. Their teeth were well suited for stripping vegetation."
The dinosaur's fossil remainsa chest plate, two lower leg bones, and an ankle bonelink it to an advanced group of sauropods called titanosaurs.
Titanosaurs are thought to have been a highly successful dinosaur group, because their fossils have been found throughout the world.
Despite this, the rich fossil beds of Mongolia have yielded very few sauropod remains.
"They're rare in general in the Gobi desert, so this fossil is helping us see what kind of sauropods were around in an area which has yielded all these other different kinds of dinosaurs," Ksepka said.
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