National Geographic News
Paleontologists today unveiled a sauropod dinosaur with a stubby neck. The discovery smudges the common picture of sauropods as unspecialized, lumbering dinosaurs that used very long necks to munch away at any greenery in sight, including treetops.
Sauropods were the largest animals ever to walk on land. They are characterized by their small heads, elephant-like limbs, and long tails and necks. Some sauropods' necks were four times as long as their backs.
The new dinosaur, Brachytrachelopan mesai, measured less than 33 feet (10 meters) long, making it unusually small for a sauropod. Its neck was shorter than its backbone.
"It is by far the shortest neck reported in any sauropod," Oliver Rauhut, a paleontologist with the Bavarian State Collection for Paleontology and Geology in Munich, Germany, said in an e-mail to National Geographic News.
Rauhut and German and Argentinean colleagues report the discovery in tomorrow's issue of the journal Nature.
The dinosaur was discovered in Argentina's Patagonia region by Daniel Mesa, a local farmer. Mesa was looking for stray sheep when he came across the dinosaur fossil. Brachytrachelopan mesai translates to "Mesa's short-neck shepherd god." Rauhut and colleagues date the new dinosaur to the late Jurassic period, about 150 million years ago.
The Brachytrachelopan fossils include most of the dinosaur's neck and back vertebrae, all the ribs, portions of the pelvis, and fragments of the hind legs. The rest of the fossils were destroyed by erosion in the last thousand years or so, Rauhut said.
Brachytrachelopan's neck vertebrae are remarkably short for a sauropod: Each individual vertebra is as long as or shorter than it is tall. In other sauropods, the neck vertebrae are at least twice as long as they are tall, according to Rauhut.
The short neck, Rauhut said, was likely an adaptation to eating an abundant or nutritious low-growing planta niche that may have limited Brachytrachelopan's size.
In addition, an analysis of the vertebrae fossils indicate Brachytrachelopan was unable to lifts its neck above the horizontal, meaning it was unable to crane its neck up into the treetops.
Adam Yates is a paleontologist at the University of the Witwatersrand in Johannesburg, South Africa. He commented in an e-mail that the discovery of the short-neck sauropod is exciting and confirms an unusual sauropod body plan that earlier discoveries had suggested.
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