Analysis of fossilized teeth from Ellesmere Island, Canada, reveals that extinct relatives of monkeys and apes arrived in the Arctic during a period when the climate was warmer.
25 January 2023
Tree-dwelling relatives of primates lived in the swampy forests of the Arctic 52 million years ago, when the climate was about 13°C warmer than it is today.
“These creatures are the first and only primate relatives known to have reached the Arctic,” says Kristen Miller of the University of Kansas.
Primates, which include monkeys and apes, are descended from squirrel-like mammals that survived the mass extinction that killed off most of the dinosaurs 66 million years ago.
Miller and his colleagues took pictures of around 40 tooth and jaw fossils that had previously been collected from Ellesmere Island, Canada, which lies within the Arctic Circle. Previous studies had dated the fossils to 52 million years ago, but did not identify which species they were.
Using statistical analysis to compare the size and curvature of fossilized teeth with those of living and extinct primate relatives, the team discovered two new species of primate relatives, which they named ignacio mckennai Y ignacio dawsonae after the paleontologists who first collected them.
“Mammals have very complicated dental anatomy, which means we can use teeth as fingerprints at a crime scene to tell one species from another,” says Chris Beard, also from the University of Kansas.
Other species of the genus ignacio they have been found in other parts of North America, but their exact relationship to modern primates is subject to debate.
The team’s analysis suggests that Arctic-dwelling species likely evolved from a chipmunk-like ancestor that migrated north from mid-latitude regions of North America as the climate warmed. Compared to their common ancestor, I.dawsonae would have been twice as big and i.mckennai four times larger, says Beard.
The analysis of the teeth also revealed that the creatures likely evolved to eat a diet of hard nuts and tree bark to cope with the lack of softer fruits, which are supposed to be their food of choice, during the six months that they are missing. sunlight so far north.
The findings provide insight into how animals can cope with global warming. “Some types of animals are likely to move north into the Arctic, but many others will not be able to, in the same way that our ignacio species made it, but many other primates living at lower latitudes didn’t,” says Beard. Other animals living on Ellesmere Island at the time included crocodiles and tapirs, Miller says.
“This is important for broadening our perspective on past primate biology and geographic ranges,” says Kenneth Rose of Johns Hopkins University in Maryland. “The diagnoses of the two new species are appropriate and scientifically sound. Dietary inferences are reasonable.”
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