Arctic fossil is the northernmost rhinoceros species ever found

Millions of years ago, a pony-sized, hornless rhinoceros roamed the forests and ate leaves in what is now northern Nunavut, making it the northernmost rhinoceros ever found.

A new study published Tuesday identifies it as a new species, and offers an interesting explanation for how it got there.

Epithecarium Itzilik It was about the size of a modern Indian rhinoceros and was much smaller than the African rhinoceros, standing about a meter at the shoulder, said Danielle Fraser, lead author of the new study. Published in the journal Nature Ecology and Evolution,

Researchers found more than 70 percent of the animal’s skeleton in Houghton Crater on Devon Island, about 1,000 kilometers north of the Arctic Circle – breaking the record for the northernmost rhinoceros ever found. determined by yukon sample,

From its skull, teeth and other bones they were able to learn a lot about it.

The wear on his teeth showed that he was in early to middle adulthood.

Co-author of the new study, paleontologist Natalia Rybzynski of the Museum of Nature and Carleton University, said researchers believe the rhinoceros was female. This is partly due to the small size of the lower teeth, which are much larger in male rhinos.

In an artist’s reconstruction, a hairy rhinoceros with wide nostrils and no horns stands near lilies, swans and a bird on the shore of a lake. beaverIn the background, there is a forest of pine and spruce, along with maple, birch and alder in autumn colors, and the northern lights spreading across the twilight sky.

“I wanted the artists to make the rhinoceros look like a pony in winter,” said Fraser, head of paleontology at the Canadian Museum of Nature in Ottawa.

While the climate was similar to that of southern Ontario today, winters would have been snowy, and Fraser reasoned that the animal would have had to stay warm during the long dark winters in its polar home.

In fact, its species name is the Inuktitut word for “Frosty” or “Frost” and was chosen by Jarlu Kigutak, an Inuit elder from Grise Fiord who worked with some paleontologists on fossil collecting trips to Devon Island and Ellesmere Island.

Fraser said the new species walks on four toes instead of the three toes used by most rhinos: “It’s a little strange in that sense.”

Interestingly, the fact that it did not have a horn is not unusual – most fossil rhinoceros were hornless, despite the name “horned-nosed”, which comes from their modern descendants.

Overall, however, the new species is quite different from the dozens of fossil rhinoceros species that roamed North America. Instead, it has been combined into a genus of similar species found in Europe, epithecarium,

This raised the question of how it ended up on the island of Devon. Previous studies had shown that there was a land bridge between Europe and North America – but it broke down about 33 million years ago E. Itzilik Use to live.

The researchers propose that the discovery of this rhinoceros provides evidence that during the early Miocene some animals could cross despite there still being water between the islands.

“At different times … in the winter there may actually have been some ice there that would have allowed them to get through,” Fraser said.

40 years wait

Whereas E. Itjilik A new species has just been discovered, its first bones discovered four decades ago by Mary Dawson, a paleontologist and curator at the Carnegie Museum of Natural History who co-authored the new study, who died in 2020.

where is the lake E. Itjilik Once had a drink in Houghton Crater, a huge crater formed by an asteroid impact on the island of Devon. The artist’s image of the rhinoceros includes steam from a hydrothermal vent in the background, which is believed to have opened due to the impact.

Rybczynski says the lake has long since dried up, leaving behind a polar desert that has been a rich source of fossil fragments.

The fossils found there include many fishes, swans, ducks etc. beaver ancestor of seals“Tons” of rabbits and a shrew – several of which appear in the artist’s reconstruction.

This was a time when large predators such as a variety of horses, camels, rhinoceros and saber-toothed cats roamed North America – although so far, the rhinoceros is the only large animal found in Houghton Crater.

The Arctic freeze-thaw cycle causes the ground at the site to be repeatedly turned over, brought to the surface, buried, and bone fragments are dispersed over wide areas.

Paleontologists shake them off dusty soil, then bag them and bring them back to the museum. But putting them back together can be a long, challenging process. Rybczynski said that when the bones are laid out, “on that side we have a table of scraps” that researchers hope to someday identify and keep.

When Dawson found the first rhino bones in 1986, he immediately knew it was a rhinoceros, Fraser said, because rhinos have distinctive bands on their teeth.

After returning to the Carnegie Museum, Dawson showed the bones to some fossil rhinoceros experts. One of them was Donald Prothero, a geology professor at California State Polytechnic University, who has since written a book on the fossil rhinos.

He said the animal’s teeth and four toes resembled those found in some very ancient rhinoceros, but none as young as 23 million years ago.

“I said, ‘Well, it’s a very strange animal, good luck,'” Prothero recalled.

He suggests that this is one reason it took so long to conduct an in-depth study.

A team including Dawson and Rybczynski returned to the fossil site several times in the late 2000s and ultimately succeeded in finding about 70 percent of the skeleton.

Jailyn Eberle, a Canadian paleontologist at the University of Colorado Boulder who studies Arctic mammal fossils, said it is very unusual to find such a complete fossilized skeleton, especially in the Arctic. Most of the time, all you get are “little bits and pieces, maybe part of a jaw, maybe a tooth.”

She said considering how much of the animal she has, she feels confident about the results.

Both she and Prothero said they were surprised by the study’s suggestion that animals used a land bridge between Europe and Asia for much longer than previously thought.

“It’s very interesting and very exciting,” Eberle said. She further said that this makes her want to find more evidence of animal movement in that area.

Like Prothero, she and other fossil mammals have long known about this rhinoceros fossil and are excited to learn more.

“We’ve been waiting for this.”