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

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

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

The now-extinct creatures belonged to part of the primate family tree that branched out before lemur ancestors diverged from the common ancestors of apes, apes and humans, said study co-author Dr. Chris Beard, a distinguished professor of ecology and evolutionary biology at the University of Kansas and senior curator of the university’s Biodiversity Institute and Natural History Museum.

The two sister species lived on what is now Ellesmere Island in northern Canada. They are the first known primatomorphans, or relatives of primates, to have lived at 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 about half the size of a domestic cat,” Beard said. “Unlike living primates, Ignacius had eyes on the sides of its head (rather than facing forward like ours) and had claws on its fingers and toes instead of nails.”

When researchers analyzed the fossil fragments, Ignacius’ jawbones and teeth looked different from those of other primatomorphans that lived in the more southern reaches of North America.

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

The Arctic primatomorphans evolved special features in their jaws and teeth to chew harder foods, such as nuts and seeds, as opposed to their preferred diet of ripe fruit. This physical adaptation was probably because the species lived in the darkness of the Arctic winter for half of the year, when food was much harder to find.

“That, we think, is probably the biggest physical challenge of the ancient environment for these animals,” Beard said.

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

Researchers believe the primatomorphans descended from an ancestral species that moved north from the more southern regions of North America. Similar fossils have been found in Wyoming, Texas, Montana and Colorado, according to Miller.

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

The common ancestor of the two Ignacius species likely reached Ellesmere Island about 51 million years ago, Beard said. At the time, it was a peninsula jutting into the Arctic Ocean from neighboring parts of North America.

Ignacius mckennai and Ignacius dawsonae are named in part after two of Beard’s former colleagues and mentors, he explained: the late 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 worked extensively on Ellesmere Island.

During these ancient times, the Arctic Circle was a warmer, more hospitable place for life. Global warming had made the region much warmer and wetter, with a swampy environment. The warmer temperatures during this period likely encouraged Igancius’s ancestor to move north.

“Winter temperatures may have been as low as freezing for short periods, but we know there were almost never sustained temperatures below freezing because crocodilians have been found on Ellesmere Island, and they can’t survive long freezes,” Beard said. “In the summer, temperatures reached about 70 degrees Fahrenheit.”

Despite the warmer temperatures, the primatomorphans still had to adapt to survive in their unique northern ecosystem. They grew larger than their southern relatives, which resembled squirrels; such growth is common in mammals living in northern latitudes because it helps them maintain needed body temperature, Beard said.

“(The findings) tell us that we can expect dramatic and dynamic changes in the Arctic ecosystem as it transforms in the face of continued warming,” Beard said. “Some animals not currently living in the Arctic will colonize that region, and some will adapt to their new environment in ways similar to Ignacius. Likewise, we can expect some of the new settlers to diversify into the Arctic, just as Ignacius did.

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