Dinosaurs once lived and bred in Alaska | Polarjournal
This 14-millimeter fragment of a jawbone along with the tooth showed that dinosaurs lived and bred in Alaska during the late Cretaceous period. Picture: Chiarenza et al (2020) PLOS ONE

Dinosaurs in the polar regions are no longer fantasy. Numerous fossil finds in the south and the north have shown that these huge lizards also had made their appearance there. Also in Alaska, finds have shown that the animals had been in the region. Until now, however, it was assumed that they had only been in transit. Now an international team of researchers has made an exciting find: parts of a jawbone of a baby raptor dinosaur.

The research group of British and American scientists found the fragment, which consists of jawbones and tooth, in the far north of Alaska. The researchers’ analysis shows that the fragments are about 70 million years old and had belonged to a so-called dromaeosaurid, a predatory dinosaur. This group of dinosaurs is probably known to many as Velociraptor or Deinonychus through Jurassic Park. Modern results have shown that this world-wide dinosaur group was more closely related to birds and probably also wore feathers. Since many of them were rather lightly built as gliders and runners, finding fossils of this group is an extraordinary stroke of luck, as rarely the bones remain intact.

“For some time afterwards, there was a great debate as to whether or not those Arctic dinosaurs migrated or lived in the north year round.”

Dr. Antonio Fiorillo, Southern Methodist University, TX

Until now, the presence of this dinosaur group in Alaska was only documented by dental finds. “Years ago, when dinosaurs were first found in the far north, the idea challenged what we think we know about dinosaurs,” explains co-author Antonio Fiorillo of Southern Methodist University in Texas. “For some time afterwards, there was a great debate as to whether or not those Arctic dinosaurs migrated or lived in the north year round.”

Thanks to new findings, we now know that certain dinosaur species coped with the harsh conditions of the northern climate. Animals like these dromaeosaurs were probably able, like the birds nowadays, to adjust their body temperature accordingly. Photo: Andrey Atuchin

For a long time it was assumed that dinosaurs, like today’s lizards, were poikilothermic, i.e. they could not regulate their body temperature like mammals or birds. In the meantime, however, it is known that many species were quite capable of this. This included the dromaeosaurids. This ability is an essential component for surviving colder regions. It is true that Alaska had more moderate conditions during the late Cretaceous period. But its location far to the north led to long and cold winters even back then. Therefore, it was assumed that dinosaurs only roamed Alaska or wandered back and forth at that time, but did not live there.

“One might even say, our study shows that the ancient north was a great place to raise a family.”

Dr. Antonio Fiorillo, Southern Methodist University, TX

The findings by Alfio Chiarenza, the first author of the study, now paints a different picture: Certain dinosaur species probably lived in the region all year round and were able to deal with the conditions. “Even with such an incomplete jaw fragment, our team was not only able to work out the evolutionary relationships of this dinosaur, but also to picture more about the biology of these animals, ultimately gainig more information on this ancient Arctic ecosystem,” Chiarenza says. Dr Fiorillo also believes that the find is the first real evidence that dinosaurs actually lived in the far north. “One might even say, our study shows that the ancient north was a great place to raise a family. Now we just have to find out why.”

The Dromaeosaurs were a diverse group of predatory dinosaurs, but they had some characteristics in common. These included the claw with which they probably killed their victims, and a long, tail, often covered with feathers. Their size was barely that of an adult, but could also be smaller. Photo: Fred Wierum, Wikipedia CC BY-SA 4.0

Dr Michael Wenger, PolarJournal

Link to the study:

Chiarenza AA, Fiorillo AR, Tykoski RS, McCarthy PJ, Flaig PP, Contreras DL (2020) The first juvenile dromaeosaurid (Dinosauria: Theropoda) from Arctic Alaska. PLoS ONE 15(7)

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