14 abr 2012
Among those roaming the high latitudes 70 million years ago were the plant-eating duck-billed Edmontosaurus, which was 12 metres long and weighed 4,000 kilograms and the horned dinosaur Pachyrhinosaurus, which lived during a period marked by severe climate changes, lowered sea levels, and high volcanic activity.
It’s yet another chapter in humans’ fascination with dinosaurs as well as a glimpse of what to expect from climate change in the north, researchers say.
The far north then did not have the kind of extreme cold that exists now but was more comparable to weather experienced along the southern portion of Canada. But like now it had long periods of darkness during winter.
“The Arctic is not the kind of place you normally think of when you think of dinosaurs but yet there they are,” Tony Fiorillo, a paleontologist at the Museum of Nature and Science in Dallas, Texas, told the Toronto Star Thursday.
“The work my group has done is come up with a number of ways to argue that they were non-migratory,” he said.
Fiorillo, who has been excavating Cretaceous Period fossils along Alaska's North Slope since 1998, enlisted the help of Allison Tumarkin-Deratzian, an assistant professor of earth and environmental science at Temple University in Philadelphia who had both expertise and the facilities to create and analyze thin layers of the dinosaurs' bone microstructure.
They then turned to Anusuya Chinsamy-Turan, a professor of zoology at the University of Cape Town, who was independently pursuing the same analysis of Alaskan Edmontosaurus fossils. Together they published their findings, “Hadrosaurs Were Perennial Polar Residents,” in the April issue of the journal The Anatomical Record: Advances in Integrative Anatomy and Evolutionary Biology.
The study, which was funded through a grant from the National Science Foundation, looked at the cell structure of the bones that Fiorillo collected in Alaska.
“The bones from these young animals . . . basically told us that they weren’t growing at a constant rate throughout life” providing further proof that they were affected by seasonal change, Tumarkin-Deratzian said.
Fiorillo said the discovery of high latitude dinosaurs challenges the notion that reptiles were supposed to live in a very warm tropical swampy environment.
“And here they are living in a place that nobody really would have predicted,” he told the Star.
The information from the study, Fiorillo said, gives mankind some insight into what to expect from climate change in the north.
“The work that we are doing, as well as a group from the Royal Ontario Museum, is important because it tells us something about an ancient Arctic ecosystem . . . and I think we have something to add to the discussion about what will a warmer world look like because there is clearly a thriving environment 70 million years ago living in the Arctic,” he said.
