Cat-sized primates lived in the Arctic 52 million years ago

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Analysis of fossils found in the far north of Canada has revealed that two previously unknown species of ancient quasi-primates lived above the Arctic Circle around 52 million years ago, according to new research. .

The now-extinct creatures belonged to a part of the primate family tree that branched off before the ancestors of lemurs diverged from the common ancestors of apes, great apes and humans, said the co-author of the study, Dr. Chris Beard, Distinguished Professor of Ecology and Evolutionary Biology at the University of Kansas and Senior Curator at the University’s Biodiversity Institute and Museum of Natural History.

The two sister species lived on what is now Ellesmere Island in northern Canada. They are the first known primatomorphs, or relatives of primates, to have lived in latitudes north of the Arctic Circle, according to a study published Wednesday in the journal PLOS ONE.

The two species have been named Ignacius mckennai and Ignacius dawsonae.

“To get an idea of ​​what Ignacius looked like, imagine a cross between a lemur and a squirrel that was about half the size of a house cat,” Beard said. “Unlike living primates, Ignacius had eyes on the sides of his head (instead of facing like ours) and he had claws on his fingers and toes instead of nails.”

When the researchers analyzed the fossil fragments, the jaws and teeth of Ignacius looked different from those of other primatomorphs that lived in more southern regions of North America.

“What I’ve been doing for the past two years is trying to understand what they were eating and whether they were eating different foods than their mid-latitude counterparts,” said the lead author of the study, Kristen Miller, PhD student at the University of Kansas Biodiversity Institute and Museum of Natural History.

Arctic primatomorphs have evolved special features in their jaws and teeth for chewing harder foods, such as nuts and seeds, as opposed to their preferred diet of ripe fruit. This physical adaptation was likely due to the fact that for half of the year the species lived in the darkness of the arctic winter, when food was much harder to find.

“We think that’s probably the biggest physical challenge of the ancient environment for these animals,” Beard said.

These findings could also be used to understand how animals adapt and evolve amid periods of climate change – such as species facing the human-induced climate crisis today.

Researchers believe primatomorphs are descended from an ancestor species that roamed the north of the southernmost regions of North America. Similar fossils have been found in Wyoming, Texas, Montana and Colorado, according to Miller.

“No primate relatives have ever been found at such extreme latitudes,” Miller said. “They are more commonly found around the equator in tropical regions. I was able to do a phylogenetic analysis, which helped me understand how the fossils from Ellesmere Island are related to species found in the mid-latitudes of North America.

The common ancestor of both Ignacius species likely reached Ellesmere Island around 51 million years ago, Beard said. At the time, it was a peninsula that jutted into the Arctic Sea from adjacent parts of North America.

Ignacius mckennai and Ignacius dawsonae are partly named after two of Beard’s former colleagues and mentors, he explained: deceased paleontologists Dr. Mary Dawson of the Carnegie Museum of Natural History in Pittsburgh and Dr. Malcolm McKenna of the American Museum of Natural History in New York, both of whom have worked extensively on Ellesmere Island.

During those ancient times, the Arctic Circle was a warmer and more hospitable place to live. Global warming had made the region much warmer and more humid, with a marshy environment. The warmer temperatures during this period likely encouraged Igancius’ ancestor to venture north.

“Winter temperatures may have reached freezing point for short periods, but we know that there have hardly ever been sustained freezing temperatures because crocodilians have been found on Ellesmere Island and they can’t survive long freezes,” Beard said. “In the summer, temperatures were around 70 degrees Fahrenheit.”

Despite warmer temperatures, primatomorphs still had to adapt to survive in their unique northern ecosystem. They grew larger than their southern relatives, which looked like squirrels; such growth typically occurs in mammals living in northern latitudes because it helps them maintain the necessary core body temperature, Beard said.

“(The results) tell us to expect dramatic and dynamic changes to the Arctic ecosystem as it transforms in the face of continued warming,” Beard said. “Some animals that do not currently live in the Arctic will colonize this region, and some of them will adapt to their new environment in a way parallel to Ignacius. Likewise, we can expect some of the new settlers branched out into the Arctic, just as Ignacius did.