William Stout |

Antarctica Then
This artist's illustration shows what the newly discovered dinosaur, Glacialisaurus hammeri, may have looked like in its Antarctic environment during the Early Jurassic, with several pterosaurs in the background and a small mammal-like reptile in the foreground. The new dinosaur genus and species was described by Nathan Smith, a graduate student at The Field Museum in Chicago, and Diego Pol, a paleontologist at the Museo Paleontologico in Chubut, Argentina.

Dec. 14, 2007 -- Using jackhammers, rock saws and chisels at a punishing 14,000 feet, paleontologists working atop a frozen Antarctic mountain have extracted a rock and ice fossil popsicle encasing the remains of a massive, previously unknown dinosaur.

The dino, which represents a new genus and species, lived 190 million years ago during the Early Jurassic at what is now Mt. Kirkpatrick, near the Beardmore Glacier. The species adds to a growing number of dinosaurs known to have roamed the now-polar continent.

Named Glacialisaurus hammeri, after noted Antarctica fossil hunter William Hammer, the new dino was identified by a femur leg bone and an incomplete ankle and foot.

"Scaling the material up to similar-sized relatives would suggest that it was around 25 feet long and weighed perhaps 4-6 tons," said Nathan Smith, a graduate student at Chicago's Field Museum and a member of the Committee on Evolutionary Biology.

Smith, along with paleontologist Diego Pol of Argentina's Museo Paleontologico Egidio Feruglio, describe the anatomy of the new sauropodomorph dinosaur in this month's Acta Palaeontologica Polonica.

Sauropodomorphs, with their incredibly long necks, tails and classic dino shape, were the largest animals ever known.

"Throughout the evolution of sauropodomorphs, there appears to be a general trend of increasing body size, and Glacialisaurus would likely fit somewhere in the middle of this evolutionary trend," Smith said.

He explained to Discovery News that this group is generally considered to be plant consumers, although some earlier members -- perhaps even the new dino -- may have eaten almost anything in sight, with plants providing the bulk.

Bones of another Antarctic dinosaur, still under preparation, suggest G. hammeri coexisted for a time with true sauropods, a related but distinct group of dinos.

Smith said this "tells us that animals that probably had overlapping ecological roles were present in the same environment. Either these groups were directly competing with each other for resources, or they somehow occupied slightly different niches within the environment."

That environment, and climate, was very different than it is today, said Thomas Wagner, program director of Antarctic Earth Sciences at the National Science Foundation (NSF), which supported the research.

Then warmer, Antarctica's Early Jurassic climate likely supported ultra-tall trees that sauropodomorphs, like giraffes on steroids, were adept at eating.

Positioned further north, the continent was also then connected to other landmasses.

Wagner described Antarctica as a Jurassic "freeway," since "it was the route by which dinosaurs and mammals moved from places like Africa to Australia. Then, once it broke away, it may have been a refuge, albeit a cold one."

Even back in G. hammeri's day, Wagner said Antarctica would have forced the dinosaur and its relatives to endure "a long, cold, dark winter, yet similar animals lived in places like China."

"How did they do that?" he wondered.

Both Wagner and Smith hope lengthier fieldwork in Antarctica might solve this question, as well as other dinosaur mysteries concerning the planet's southernmost continent.