A discovery made in the far north of Alaska opened a new stage in the study of polar Cretaceous ecosystems. Researchers identified three unknown species of mammals that inhabited the region approximately 73 million years ago, in an environment marked by extreme temperatures and long periods of darkness.
The fossils were found in the Prince Creek Formation, an area near the Arctic Circle that had already provided evidence of dinosaurs and reptiles adapted to the northern climate. However, this new finding demonstrates that small mammals also managed to develop in conditions much more complex than previously thought.
The study was led by specialists from the University of Lincoln along with scientists from various international institutions, who analyzed fossil teeth preserved in the frozen strata of Alaska.
Additionally, the researchers argue that this polar ecosystem functioned as a key space for the evolution and diversification of species capable of withstanding prolonged winters and seasonal food scarcity.
New species adapted to cold and darkness
The discovered species were named Camurodon borealis, Qayaqgruk peregrinus, and Kaniqsiqcosmodon polaris. All belong to the group of multituberculates, ancient mammals characterized by their teeth with multiple cusps, adapted to grind different types of food.
The analysis of the dental pieces allowed the reconstruction of part of their life habits. In the case of Camurodon borealis, scientists detected a dentition specialized in processing vegetation, indicating a primarily herbivorous diet.
On the other hand, Qayaqgruk peregrinus showed characteristics compatible with an omnivorous diet. This flexibility would have been fundamental to survive in an environment where the availability of resources varied drastically according to the season.
Likewise, Kaniqsiqcosmodon polaris presented a combination of traits that make it the oldest known member of the family Microcosmodontidae. Its discovery suggests that some mammal lineages may have originated in polar regions before expanding to other areas of the northern hemisphere.
The Arctic as a prehistoric biological corridor
One of the most relevant aspects of the study is related to the ancient migrations between continents. Scientists found evolutionary links between Qayaqgruk peregrinus and species previously found in Mongolia.
This connection provides new evidence of the existence of a land corridor between Asia and North America during the Cretaceous, used by small mammals to move between both continents.
In this way, the Arctic ceases to be seen solely as a climatic barrier and is interpreted as an active route for the dispersal of species and the generation of biodiversity.
Additionally, researchers consider that these polar adaptations may have been crucial for some multituberculates to survive the mass extinction that eliminated non-avian dinosaurs 66 million years ago.
What is known about these new species discovered in Alaska
The three identified species represent an exceptional evidence of the adaptive capacity of prehistoric mammals in extreme environments.
Camurodon borealis stood out for its specialized dentition to consume cold-resistant plants, while Qayaqgruk peregrinus developed a varied diet based on insects and vegetables.
Meanwhile, Kaniqsiqcosmodon polaris showed a complex dental structure that evidences a significant evolutionary diversification in polar areas.
The fossils found also reveal that these small animals coexisted with hadrosaurids, raptors, and other dinosaurs in a dynamic ecosystem that maintained biological activity even during long dark winters.
Although there are still questions about how they regulated their metabolism or endured the months without sunlight, scientists believe that future findings in the Prince Creek Formation will allow a better understanding of the evolution of the first mammals adapted to the Arctic.
The discovery also reinforces the ecological and scientific importance of polar regions, today threatened by the advance of climate change and accelerated melting.
