Millions of years ago, the pony-sized hornless rhino roamed the forests and chewed leaves in what is now northern Nunavut, making it the northernmost rhino ever seen.
A new study published Tuesday identifies it as a new species and offers an intriguing explanation for how it got there.
Epiateracerium itzhilik It was about the size of a modern Indian rhinoceros and much smaller than the African rhinoceros, standing about a meter tall at the shoulder, according to Danielle Fraser, lead author of the new study. published in the journal Nature Ecology and Evolution..
Researchers discovered 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 previous record for the northernmost rhinoceros. installed by Yukon instance.
From his skull, teeth and other bones they were able to learn a lot about him.
The wear on the teeth indicated that the age was early to middle age.
Natalia Rybczynski, a paleobiologist at the Nature Museum and Carleton University and co-author of the new study, said researchers believe the rhinoceros was female. This is due to the small size of some of the lower teeth, which are usually much larger in male rhinos.
In the artist's reconstruction, a shaggy rhinoceros with wide-set nostrils and no horns stands on the shore of a lake next to lilies, swans and otter-like creature. In the background is a forest of pine and spruce, as well as maple, birch and alder in autumn colors, while the northern lights waft in the twilight sky.
“I wanted the artist to make the rhinoceros look like a pony in winter,” said Fraser, head of paleobiology at the Canadian Museum of Nature in Ottawa.
Although the climate was similar to that of southern Ontario today, the 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 an Inuktitut word meaning “frosty” or “frost” and was chosen by Jarloo Kigutak, an Inuit elder from Gris Fiord who worked with some paleontologists on fossil collecting trips to Devon and Ellesmere Islands.
Fraser said the new species walks on four toes instead of three like 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 rhinoceroses were hornless, despite the name “horned nose” which came from their modern descendants.
Overall, however, the new species is very different from the dozens of fossil rhino species that roamed North America. Instead, it was added to a genus of similar species found in Europe. Epiateracerium.
This led to questions about how he ended up on Devon Island. Previous research suggested that there was a land bridge between Europe and North America, but it collapsed about 33 million years ago. E. itzhilik lived
The researchers suggest that the discovery of this rhinoceros suggests that some animals were still able to cross here in the early Miocene, even though there was water between the islands at the time.
“At different points in time… there may have actually been ice there in the winter that allowed them to cross the border,” Fraser said.
40 year wait
Bye E. stop had just emerged as a new species, its first bones were discovered four decades ago by Mary Dawson, a paleontologist and curator at the Carnegie Museum of Natural History who posthumously co-authored the new study after passing away in 2020.
Lake where E. stop once drank in Haughton Crater, a huge hole created by an asteroid impact on Devon Island. The artist's impression of the rhinoceros includes steam in the background from hydrothermal vents believed to have been opened by the impact.
The lake has long since dried up, leaving behind a polar desert that was a rich source of fossil fragments, Rybczynski says.
Fossils found there include many fish, swans, ducks, otter-like ancestor of seals“tons” of rabbits and a shrew—many of which feature in the artist’s reconstruction.
This was a time when many species of horses, camels, rhinoceroses and large predators such as saber-toothed cats roamed North America – although to this day the rhinoceros is the only large animal found in Haughton Crater.
Arctic freeze-thaw cycles cause the ground at the site to frequently turn over, floating to the surface, burying and scattering bone fragments over wide areas.
Paleontologists clear them from the dusty soil, then put them in bags and bring them back to the museum. But putting them together can be a long and difficult process. Rybczynski said that once the bones are laid out, “we have a table on the side with scraps” that researchers hope to someday identify and place.
When Dawson found the first rhino bones in 1986, she immediately knew it was a rhino because rhinos have distinctive stripes on their teeth, Fraser said.
Back at the Carnegie Museum, Dawson showed the bones to some rhino fossil experts. One of them was Donald Prothero, a professor of geosciences at California State Polytechnic University who has since written a book on fossil rhinoceroses.
He noted that the animal's teeth and four toes resembled those of some very ancient rhinoceroses, but none were as young as 23 million years ago.
“I said, 'Well, that's a very strange animal, good luck,'” Prothero recalls.
He speculates that this is one of the reasons why the thorough study took so long.
The team, which included Dawson and Rybczynski, returned to the fossil site several times in the late 2000s and ultimately managed to recover about 70 percent of the skeleton.
Jaylin Eberly, a Canadian paleontologist at the University of Colorado Boulder who studies Arctic mammal fossils, said it was very unusual to find such a complete fossil skeleton, especially in the Arctic. In most cases, you only find “small pieces, fragments, maybe part of a jaw, maybe even one tooth.”
She said considering how many animals they had, she was confident in the results.
Both she and Prothero said they were intrigued by the study's suggestion that the animals had been using the land bridge between Europe and Asia for much longer than previously thought.
“It's pretty interesting and exciting,” Eberle said, adding that it makes her want to look for more evidence of animal crossings in the region.
Like Prothero, she and other fossil mammals have known about this rhino fossil for a long time and are looking forward to learning more.
“We've been waiting for this.”
