Return of the dinosaur (hunters)
Paleontologists continue 20-year recovery of carnivore, discover new fossils
Posted April 15, 2011
Paleontologists working on a high peak in the central Transantarctic Mountains have recovered more than half of the fossils belonging to the first dinosaur found in Antarctica — 20 years after its initial discovery.
And the unearthing of yet two new Early Jurassic dinosaur species near the top of 4,528-meter-high Mount Kirkpatrick promises to keep scientists busy for years to come preparing and describing the important finds.
William Hammer , a professor at Augustana College , led the team that discovered Cryolophosaurus, a nearly 7-meter-long carnivore two decades ago while working from a field camp near the Beardmore Glacier.
“In 90-91, we didn’t know what we had except that it had to be entirely new because it was the first dinosaur,” said Hammer, who returned to the Beardmore region for a third time with his largest team to date in an effort to recover as much of the meat-eating dinosaur as possible.
“It will be one of the most, if not the most, complete predator from the Early Jurassic that we have. It will be quite an impressive specimen,” said Peter Makovicky , curator at the Field Museum , where Cryolophosaurus will eventually reside.
Among the new discoveries is the partial skeleton of an ornithischian, or bird-hipped dinosaur, found under an overhang near the Cryolophosaurus quarry by Roger Smith in the waning days of the field season.
The ornithischia, an extinct herbivore, gets its name from its bird-like hip structure, though birds did not descend from this particular order of dinosaurs. The order includes the genus of the well-known stegosaurus, which emerged in the late Jurassic. Like Cryolophosaurus, the ornithischian specimen also dates to the Early Jurassic, about 200 to 175 million years ago.
In addition, bits of a pelvis bone belonging to a dinosaur in the order saurischia (lizard-hipped) from the Early Jurassic were found quite by accident when loose pieces rolled downhill by one of the team members. The remainder of the hip bone was excavated a few days later.
Making his first trip to the Antarctic, Makovicky said there are few places in the world where paleontologists can expect to recover such early remains of dinosaurs.
“It’s not a well-represented time slice in terms of diversity, especially compared to the Late Cretaceous, which is much better known for its dinosaur diversity around the world,” he said, referring to a time period between 100 and 65 million years ago when dinosaurs were enjoying great success — before their sudden extinction at the end of the Cretaceous.
Makovicky said such a complete, early skeleton becomes invaluable for studying other specimens — a sort of paleontological Rosetta Stone.
“That specimen becomes key, or a guiding specimen, for interpreting the anatomy of more fragmentary dinosaurs we may have from elsewhere,” he explained. “That’s why digging up every possible bone becomes very critical.”
The opportunity to work on the Cryolophosaurus excavation enticed Philip Currie to join the expedition to Antarctica. One of the world’s leading paleontologists, from the University of Alberta , Currie’s interests include carnivorous dinosaurs like the famous Tyrannosaurus rex.
“If you’re interested in the evolution and relationships of dinosaurs, then you pretty much have to look at the early dinosaurs as well,” Currie said.
Currie often works at Dinosaur Provincial Park in Alberta, a treasure trove of Cretaceous dinosaur species. Its high latitude position at the time — about 5 degrees farther north than today — suggests dinosaurs weren’t adverse to cold conditions, Currie said. He sees some parallels between the two polar sites, though migratory patterns would have been more limited in Antarctica.1 2 Next
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