A team of Scientists have described the fossil remains of a rhinoceros from the Canadian High Arctica now extinct species and the northernmost known. The almost complete skeleton was discovered in the Haughton Crater on Devon Island, in Nunavut, in the far north of Canada.
He “arctic rhinoceros” It lived about 23 million years ago, in the Early Miocene (between 23 and 5.6 million years ago), and is closely related to other species that thrived in Europe millions of years before.
Details of the new species, called Epiatheracerium itjilikwere published this Tuesday in the journal ‘Nature Ecology and Evolution’.
The evolutionary history of rhinos dates back more than 40 million years and spans all continents except South America and the Antarctica.
“Today there are only five species of rhinoceros left in Africa and Asia, but in the past they were found in Europe and North America, with more than 50 species known from the fossil record,” says the study’s lead author, Danielle Fraser, head of paleobiology at the Canadian Museum of Nature.
Fraser believes the discovery of this Arctic species in the rhino family tree now “offers new insights into our understanding of their evolutionary history.”
Additionally, the study provides evidence that the new Arctic species migrated to North America via a land bridge that may have been a passageway for the dispersal of mammals Earth millions of years later than previous evidence suggests.
The new species
Rhinos proliferated in a wide variety of shapes and sizes, from large and hippo-like to relatively small and hornless.
Epiatheracerium itjilik was relatively small and slender, similar in size to the modern rhinoceros, but without a horn. The Arctic specimen is believed to be early to mid-adult, based on moderate wear of the cheek teeth.
The species name “itjilik” means “ice cream” or “frost” in Inuktitut, after the northernmost Inuit community of Canada.
Most of the specimen’s bones were collected at the Haughton Crater site in 1986 by Mary Dawson, of the Carnegie Museum of Natural History (CMN) in Pittsburgh, Pennsylvania, and a pioneer in Arctic paleontology.
At 23 kilometers wide, Haughton Crater – the world’s northernmost Miocene site – contains remains from a time in history when modern mammal families diversified and dispersed between continents.
The crater, caused by a meteorite, filled with water, creating a lake that preserved the remains of the animals and plants of the place and which has been studied for its geological characteristics, flora and fauna.
Evidence from fossil plants shows that millions of years ago, this site was a temperate forest, far removed from today’s cold, arid conditions of permafrost, whose freezing and thawing caused the fossils to break apart and bones to come to the surface.
“What is notable about the Arctic rhino is that the fossil bones are in excellent condition. They are preserved in three dimensions and have only been partially replaced by minerals. Approximately 75% of the skeleton was discovered, which is incredibly complete for a fossil,” says paleobiologist Marisa Gilbert, co-author of the study and CMN researcher.
Evolutionary history
The team has placed the new species in the rhinoceros family tree by studying 57 other groups of rhinoceroses, almost all of them extinct.
The team also managed to geographically locate each rhinoceros in one of five continental regions. The analysis offers new insights into how rhinos dispersed over millions of years between North America and Europe (via Greenland), using the North Atlantic Land Bridge.
Previous studies had suggested that this land bridge may have functioned only as a dispersal corridor until about 56 million years ago but the new analysis with Epiceratherium itjilik and its related species suggests that dispersals occurred from Europe to North America much more recently (in the Miocene).
For the authors, this study demonstrates that the Arctic continues to offer new knowledge and discoveries that expand our understanding of mammal diversification over time.