Melbourne, Dec 17 (UNI) Palaeontologists working on top a frozen Antarctic mountain have extracted a rock and ice fossil popsicle encasing the remains of a massive, previously unknown dinosaur.
The scientists unearthed the dinosaur, which represents a new genus and species, at 4200 metres, Australian Broadcasting Corporation (ABC) reported today.
The dinosaur lived 190 million years ago during the early Jurassic period, at what is now Mount Kirkpatrick, near the Beardmore Glacier.
The species adds to a growing number of dinosaurs known to have roamed the now-polar continent.
The dinosaur is named Glacialisaurus hammeri, after the noted Antarctica fossil hunter Professor William Hammer, and 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 seven metres long and weighed perhaps 4-5 tonnes,'' said Nathan Smith, a graduate student at Chicago's Field Museum and a member of the Committee on Evolutionary Biology.
Mr Smith, along with palaeontologist Dr Diego Pol of Argentina's Museo Paleontologico Egidio Feruglio, described the anatomy of the new sauropodomorph dinosaur in this month's Acta Palaeontologica Polonica.
Sauropodomorphs, with their incredibly long necks, tails and classic dinosaur 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,'' Mr Smith said.
He said that this group was generally considered to contain plant eaters. But some earlier members, perhaps even the new dinosaur, may have eaten almost anything in sight, with plants providing the bulk, he added.
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.
''This tells us that animals that probably had overlapping ecological roles were present in the same environment,'' Mr Smith said.
''Either these groups were directly competing with each other for resources, or they somehow occupied slightly different niches within the environment,'' he added.
That environment and climate was very different than it is today, said Dr Thomas Wagner, program director of Antarctic Earth Sciences at the National Science Foundation, which supported the research.
Antarctica's early Jurassic climate was warmer than it is today and probably supported ultra-tall trees that sauropodomorphs, like giraffes on steroids, were adept at eating, he said.
Dr 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,'' he said.
Even back in G hammeri's day, Dr 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 asked.
Both Dr Wagner and Smith hoped lengthier fieldwork in Antarctica might solve this question, as well as other dinosaur mysteries concerning the planet's most southern continent.