New Extinct Rhino Species Discovered in Canadian Arctic Provides Insights into Ancient Animal Migrations

Researchers from the Canadian Museum of Nature (CMN) have identified a new species of rhinoceros that inhabited Canada's High Arctic approximately 23 million years ago. This discovery challenges existing timelines for ancient animal migrations across continents.

Epiatheracerium itjilik: A Northern Rhino

The newly identified extinct rhinoceros, named Epiatheracerium itjilik, is the northernmost rhino species known to date. It is described in the journal Nature Ecology & Evolution. Unlike modern rhinos, E. itjilik was hornless and smaller in stature. It lived in an environment that was likely a temperate forest during months of darkness. Its fossil remains were first found in Nunavut, Canada, in 1986.

Approximately 75% of the animal's skeleton has been recovered. Danielle Fraser, head of Paleobiology at CMN and lead author of the study, attributes this level of preservation to the animal's encasement in the Arctic's permafrost.

Implications for Ancient Migration

Fraser and her team analyzed the fossil's physical characteristics to determine its position within the rhino family tree. Comparisons with other specimens revealed that the closest relatives of E. itjilik resided in Europe and Western Asia. This indicates that the rhino's ancestors likely utilized the North Atlantic Land Bridge, a landmass that once connected Europe and North America.

Previously, scientists estimated that the North Atlantic Land Bridge was submerged by water around 50 million years ago, limiting its role in animal dispersal. However, the researchers' analysis suggests that rhinos made bidirectional crossings over this land bridge for at least 20 million years longer than previously thought. This finding re-evaluates the North Atlantic Land Bridge's significance and duration of impact on animal evolution.

Arctic's Role in Evolution and Ancient Proteins

The study highlights the Arctic's role in the evolution of mammals, an area often overshadowed by tropical environments in evolutionary discussions. Ongoing research and fossil discoveries in the Arctic continue to demonstrate its importance in shaping mammal development.

Marisa Gilbert, a senior research assistant at CMN and co-author, noted that the findings offer an analogue for understanding how past animals adapted to environmental changes, particularly during periods of upheaval.

The Arctic conditions also facilitated the retrieval and study of the world's oldest sequenced proteins. Ryan Sinclair Paterson, a postdoctoral fellow at the University of Copenhagen's Globe Institute, led this aspect of the research, published in Nature in July. Proteins, being more robust than DNA, offer insights into evolutionary history. The proteins extracted from the rhino's tooth enamel are approximately 21 million years old, ten times older than the most ancient DNA previously sequenced. This new tool is expected to modify current understanding of mammal evolution and enable new lines of inquiry into evolutionary trends and biogeography.

Climate Change Concerns and Indigenous Collaboration

Paterson expressed concern regarding the future of fossil-rich Arctic sites, such as the Haughton Impact Crater where the fossil was found, due to the impact of climate change. He stated that the recovery of these ancient proteins was contingent on the extreme cold conditions, and deglaciation and erosion linked to climate change threaten these archaeological and paleontological sites.

The species was named Epiatheracerium itjilik with the assistance of Jarloo Kiguktak, an Inuit elder and former mayor of Griese Fiord, near the fossil's discovery site. Itjilik means "frosty" or "frost" in Inuktitut, honoring its Arctic origin. CMN has collaborated with Kiguktak since 2008. Fraser stated that working with Indigenous communities where specimens are collected is recognized as important, and this practice is gaining prevalence. Lawrence Bradley, an adjunct professor at the University of Nebraska's Geography/Geology department, commented that this approach fosters collaborative relationships, offers local expertise, and can engage local communities, including youth.