Early primate relatives lived in the Arctic 52 million years ago

An analysis of fossilized teeth from Ellesmere Island in Canada shows that extinct relatives of marmosets and great apes reached the Arctic during a period when the climate was hotter.

The arboreal relatives of primates lived in the Arctic wetlands 52 million years ago, when the climate was about 13°C warmer than today.

“These creatures are the first and only known relatives of primates to reach the Arctic,” says Kristen Miller of the University of Kansas.

Primates, including marmosets and great apes, evolved from squirrel-like mammals that survived the mass extinction that killed most dinosaurs 66 million years ago.

Miller and her colleagues photographed about 40 tooth and jaw fossils that had previously been collected from Ellesmere Island in Canada, located above the Arctic Circle. Previous studies have dated the fossils to 52 million years ago but have not determined what species they belonged to.

Using statistical analysis to compare the size and curvature of fossilized teeth with those of extinct and living primate relatives, the team discovered two new species of primate relatives, which they named Ignacius McKennai and Ignatius Dawson after the paleontologists who first collected them.

“Mammals have very complex dental anatomy, which means we can use teeth like crime scene fingerprints to tell one species from another,” says Chris Byrd of the University of Kansas.

Other species of the genus Ignacius have been found elsewhere in North America, but their exact relationship to modern primates is a matter of debate.

The team’s analysis suggests that the Arctic-dwelling species probably descended from a chipmunk-like ancestor that migrated northward from the mid-latitude regions of North America as the climate warmed. Compared to their common ancestor, I. Dawson would be twice as large I. McKennai four times as many, Beard says.

Dental analysis also revealed that the creatures likely evolved to feed on hard nuts and tree bark to cope with a shortage of softer fruits – presumably their preferred food – during the six months when sunlight is scarce so far north.

The findings provide insight into how animals can cope with global warming. “Some species of animals are likely to move north to the Arctic, but many others won’t – just like ours. Ignacius species have succeeded, but many other primates living at lower latitudes have not,” Bird says. According to Miller, other animals living on Ellesmere Island at the time included crocodiles and tapirs.

“This is important for expanding our view of the biology and geographic ranges of primates in the past,” says Kenneth Rose of Johns Hopkins University in Maryland. “The diagnoses of the two new species are relevant and scientifically sound. The dietary implications are reasonable.”

Subscribe to Wild Wild Life’s free monthly newsletter on the diversity and science of animals, plants and other weird and wonderful creatures on Earth.