Among the rocks of Haughton Crater on Devon Island, Nunavut, an exceptionally well-preserved fossil has rewritten the history of rhinos. Scientists at the Canadian Museum of Nature have described a new species, Epiaceratherium itjilik, the northernmost rhinoceros ever discovered.
An almost complete skeleton in the heart of the Arctic
The fossil, dating from about 23 million years ago (early Miocene), comes from lake sediments rich in plant and animal remains. It is an almost complete skeleton. According to the museum, about 75 percent of the animal’s bones were recovered, including diagnostic ones such as teeth, mandibles and parts of the skull.
“Today there are only five species of rhinos in Africa and Asia, but in the past they were widespread in Europe and North America, with more than fifty species known from the fossil record,” says Danielle Fraser, lead author of the study and head of the museum’s paleobiology section. “The addition of this Arctic species to the rhinoceros family tree offers new insights into their evolutionary history.”
The analysis, published in Nature Ecology and Evolution, shows that Epiaceratherium itjilik was a small, hornless rhinoceros, similar in size to the modern Indian rhinoceros. The species name, itjilik, means “frosty” or “frost” in the Inuktitut language. The scientists chose this term in collaboration with Jarloo Kiguktak, an Inuit elder and former mayor of Grise Fiord, who has participated in several paleontological expeditions to the Arctic.
The fossil’s story has its roots in 1986, when Mary Dawson, curator emerita at the Carnegie Museum of Natural History in Pittsburgh and a pioneer in Arctic paleontology, collected the key bones-teeth, jaws and part of the skull-that would allow it to be identified as a rhinoceros. Dawson, who died in 2020, is cited posthumously as a coauthor of the study with Natalia Rybczynski and Marisa Gilbert.
“What is remarkable is that the fossil bones are in exceptional condition. They are three-dimensionally preserved and only partially mineralized. About 75 percent of the skeleton has been uncovered, which is incredibly complete for a fossil,” says Marisa Gilbert, coauthor and senior research assistant at the museum.
The evolution of rhinos between Europe and North America
The study is not limited to the description of the new species. The team constructed a new rhinoceros family tree, analyzing 57 taxa that are almost all extinct. The results suggest that rhinos crossed an ancient land bridge between Europe and North America-the North Atlantic Land Bridge-millions of years later than previously thought.
Previously, that dispersal corridor was believed to have disappeared about 56 million years ago. Instead, the inclusion of Epiaceratherium itjilik indicates migrations still occurred in the Miocene. “Our reconstructions show that the North Atlantic played a much more important role in rhino evolution than previously thought,” Fraser notes. “More broadly, this study confirms that the Arctic continues to offer us new insights into mammal diversification over time.”
Haughton Crater, now an icy desert 23 kilometers in diameter, was then a lacustrine environment covered by temperate forests. Plant fossil analyses confirm a lush ecosystem where mammals, birds and fish lived. As the permafrost froze and thawed, the remains slowly rose to the surface, allowing scientists to recover them.
The Epiaceratherium itjilik fossil is now housed in the collections of the Canadian Museum of Nature, while the preparation of the remains was completed at the Carnegie Museum of Natural History.
As Fraser points out, “It is always exciting and informative to describe a new species. But what emerges from Epiaceratherium itjilik is that the evolutionary history of rhinos, and mammals in general, also passes through Arctic ice.”
