WORLD First Antarctic dinosaur fossils shed light on Earth's past

A mountaineer who joined the expedition is the one who discovered the fossil.
CHICAGO TRIBUNE
CHICAGO -- Returning to a windy, rugged, almost impossibly cold mountainside where 13 years ago he excavated the first dinosaur fossils ever found in Antarctica, a paleontologist from little Augustana College struck new pay dirt with remains of a 200-million-year-old, 30-foot-long creature -- fossils that will eventually make their way to Chicago.
Recovering the animal's pelvis and various leg bones, William Hammer, a geology professor at the Rock Island, Ill., school, said he thinks the newly discovered fossil is an extremely early species of sauropod -- plant-eating animals that 150 million years later evolved into 100-foot giants, Earth's biggest terrestrial animals.
The fossil was discovered by the six-man expedition's only nonscientist, a mountaineer who went along simply to watch over the safety of the dinosaur prospectors.
Bad weather in December hounded Hammer's team as it worked at 12,500 feet on the side of Mount Kirkpatrick, 400 miles from the South Pole.
Earlier discovery
The expedition marked the return to the site where, in January 1991, a Hammer-led expedition found mainland Antarctica's first dinosaur, a 25-foot-long meat-eating theropod, Cryolophosaurus.
The 1991 team also recovered fragments of a still-to-be-named plant-eating prosauropod, a forerunner of sauropods, one that Cryolophosaurus may have been feeding on when the carnivore died.
Cryolophosaurus caused a sensation, important evidence that through much of Earth's history the global climate was much warmer than today.
It also helped verify the theory of Pangaea, the supercontinent that contained all the world's landmasses until it began to break apart roughly 200 million years ago, first into two supercontinents, Laurasia and Gondwanaland, then, tens of millions of years later, into today's continental landmasses.
Scientists know Africa, South America, Australia and Antarctica once formed one landmass -- Gondwanaland -- because they have found fossils of the same ancient plants and animals spread across them.
Early Jurassic period
The rock formations on Mount Kirkpatrick where Hammer has been working are some of the few to be found in the world surviving from the early Jurassic period. As such, the fossils he recovers give scientists an extremely rare look at the flora and fauna at the time early dinosaurs were still vying to dominate Earth.
Hammer wasn't able to remove all of Cryolophosaurus' bones from the site in 1991. He prospected in two other sites hundreds of miles from the Transantarctic Mountains in two subsequent Antarctic expeditions, in 1995 and 1999, so the December expedition was the first to return to Mount Kirkpatrick.
"We had marked the Cryolophosaurus site with a big stone cairn of piled-up loose rock," said Hammer, "topped with a signal flag.
"When we found it in December, the flag had been long since shredded by the strong winds that whip across the mountain, but everything else looked exactly as we had left it.
"We even found a roll of toilet paper in a burlap bag that somebody had left behind."
The National Science Foundation had funded December's expedition for three weeks of field work. The scientists slept in tents at a lower elevation about 40 miles from the site. Two helicopters assigned to their camp flew them to the site each day.
"Instead of three weeks," said Hammer, "we only got to work for a few days, first because of severe weather, then because of mechanical trouble with one of the helicopters."
Harsh conditions
Once back at the site, Hammer, Currie and three other trained excavators toiled in high winds and temperatures as low as minus 40 to pull more of Cryolophosaurus from the rock.
The sixth member of the team, Peter Braddock, 57, a New Zealand mountaineer and veteran of 22 years of Antarctic work, was assigned to the group to guide them safely across mountain terrain.
"Peter told me he didn't want to stand around while we worked, so he was going to wander to some other parts of the mountain," Hammer said.
"I asked him to keep his head down and look at the rock for fossils as he walked and showed him what to look for. If he found anything he was supposed to mark it and bring me back later."
A couple of hours later, Braddock returned and took Hammer to look at a half a dozen interesting rocks he found about a quarter-mile from the Cryolophosaurus site. Most indeed were fossils, but of ancient tree limbs rather than bone.
What was found
That turned out to be what may be one of the earliest sauropod fossils ever discovered.
"If it is what it seems to be," said Judd Case, a sauropod authority who teaches at St. Mary's College of California, "it will be a very important transitional specimen, a very early sauropod showing us how they evolved from primitive prosau-ropods.
"The prosauropods had the familiarly shaped skulls and longer necks that we see on the later, giant sauropods, but had rather spindly legs and bodies. What Bill found on this trip has the thicker, more elephantine legs of the later sauropods."
The team left most of the bone it found encased in the surrounding rock in which it became fossilized, flown to the main U.S. Antarctic base at McMurdo Sound. It will be sent to the United States by ship before spring.