for National Geographic News
Working in some of the planet's harshest conditions, fossil hunters have found two completely new species of dinosaur in Antarctica. This increases to eight the number of dinosaur species found on the perpetually frozen southern landmass.
The discoveries, made in December, were recently revealed by the National Science Foundation, the body that coordinates U.S. research in Antarctica.
The first, a 190 million-year-old plant-eater from the early Jurassic period, was found by chance on December 713,000 feet (3,900 meters) up a mountain. A mountaineer accompanying paleontologists turned up the animal's huge pelvis in an informal search only a few miles from the South Pole.
Two thousand miles (3,200 kilometers) across the continent, and less than a week later, the scant remains of another dinosaur were foundcompletely by chanceon what once was the bottom of a shallow ocean. This 70-million-year-old dinosaur is the only known Antarctic meat-eater from the late Cretaceous period and is thought to have unusually primitive features for this period. Paleontologists had to trek 8 miles daily (13 kilometers) across treacherous ice floes to reach it.
"We don't get many opportunities to go to Antarctica and there is a short weather window of opportunity each time," said veteran dinosaur hunter Judd Case of St. Mary's College of California in Moraga. Case was on the team that made the coastal discovery. "Yet [Antarctica] consistently turns up new surprises as far as life on Earth goes," he said.
Little is known about the dinosaurs that once roamed what is now Antarctica. All fossils found so far are from the margins of coastal islands or exposed mountain rock facesthe few places free of a thick ice layer. But the continent was not always so cold.
Antarctica has sat at much the same latitude for the last hundred million years. But during the Cretaceous it enjoyed a warmer, lusher climate, similar to that of the U.S. Pacific Northwest today. (The Cretaceous period started 144 million years ago and ended 65 million years ago.)
Case, his co-worker James Martin, and their team originally set out to test a theory about the migration of extinct animals by looking for marsupial fossils on Vega Island, just off the Antarctic Peninsula (the peninsula juts towards South America).
The earliest marsupials are known to be from North America, but their later representatives, and some dinosaurs, are known to be from Australia alone. The researchers believe that animals may have migrated from the Americas, through a warmer Antarctica, and on to Australia. All three continents were likely linked by land bridges during the late Cretaceous.
However, harsh weather trapped the team's boat in ice, and they were unable to pursue their original goal, Martin said. He is a paleontologist at the South Dakota School of Mines and Technology.
Disheartened, the team stopped off on James Ross Island instead. The rocks here are made up of sediments laid down in an ancient sea. As such, the team did not expect to discover fossils of any land animals here, said Martin.
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