Scientists have uncovered a new species of duck-billed dinosaur, a 30-footlong herbivore that endured months of winter darkness and probably experienced snow, in Alaska.
The dinosaur is named Ugrunaaluk kuukpikensis which means ancient grazer of the Colville River. The remains were found along the Colville River in a geological formation in northern Alaska known as the Prince Creek Formation.
"The finding of dinosaurs this far north challenges everything we thought about a dinosaur's physiology. It creates this natural question. How did they survive up here?" said Florida State University Professor of Biological Science Greg Erickson.
The dig site - the Prince Creek Formation - is a unit of rock that was deposited on an arctic, coastal flood plain about 69 million years ago.
At the time the Prince Creek Formation was deposited, it was located well above the paleo-arctic circle, about 80 degrees north latitude. So, the dinosaurs found there lived as far north as land is known to have existed during this time period.
At the time they lived, Arctic Alaska was covered in trees because Earth's climate was much warmer as a whole. But, because it was so far north, the dinosaurs likely contended with months of winter darkness, even if it was not as cold as a modern-day winter.
They lived in a world where the average temperature was about 6 degrees Celsius, and they probably saw snow.
"What we're finding is basically this lost world of dinosaurs with many new forms completely new to science," Erickson said.
Since the 1980s scientists from the University of Alaska Museum of the North, and other collaborative institutions, including Florida State University, have collected more than 9,000 bones from various animals as part of the excavation of the Prince Creek Formation.
The majority of the bones of the Ugrunaaluk kuukpikensis were collected from a single layer of rock called the Liscomb Bonebed. The layer, about 2 to 3 feet thick, contains thousands of bones of primarily this one species of dinosaur.
In this particular area, most of the skeletons were from younger or juvenile dinosaurs, about 9 feet long and three feet tall at the hip.
Researchers believe a herd of juveniles was killed suddenly to create this deposit of remains.
Researchers found that the Ugrunaaluk kuukpikensis is most closely related to Edmontosaurus, another type of duck-billed dinosaur that lived roughly 70 million years ago in Alberta, Montana and South Dakota.
But, the combination of features found in these skeletons were not present in Edmontosaurus or in any other species of duck-billed dinosaurs. In particular, researchers observed that the Ugrunaaluk kuukpikensis had very unique skeletal structures in the area of the skull, especially around the mouth.
