In the warm climate of ancient Canada, early primate relatives adapted to life in the high Arctic albeit with limited biodiversity, according to a study published Jan. 25, 2023 in the open access journal PLOS ONE by Kristen Miller of the University of Kansas and colleagues.
The Eocene epoch was a time of intense global warming and provided a crucial case study to investigate how ecosystems respond to changing climates. Fossils from Canada’s Ellesmere Island provide evidence of a warm, swampy environment about 52 million years ago, despite spending half the year in Arctic winter darkness. In this study, Miller and colleagues identify two new species, the first primate relatives ever reported from this ancient Arctic ecosystem.
Based on fossil fragments of jaws and teeth, the researchers identified the new species as close relatives of early primates, here named Ignacius dawsonae and Ignacius mckennai. Compared to similar species from more southern places, this pair has obvious adaptations for their unusual environment. Both species are relatively large, a common feature of northern mammals, and both show dentitions suggestive of a diet of hard foods, possibly an adaptation to feed on harder foods during long, dark Arctic winters where softer meals were hard to come by.
During the Eocene, the lower latitudes of North America were home to many early primate relatives, but only these two species are known from this Arctic community, adding to previous evidence that this ecosystem had limited biodiversity in comparison with more southern habitats. The researchers suggest that while warming climates enabled certain organisms to migrate north, such movement may be limited by factors such as long periods of arctic darkness. Such insights are crucial for predictions about how ecosystems might respond to modern warming climates.
The authors add: “Global warming is transforming Arctic ecosystems in ways that are difficult to predict, but ancient episodes of global warming show how future changes in the Arctic may unfold. The first primate fossils ever recovered north of the Arctic Circle show that these tropically adapted mammals were able to colonize the Arctic during an ancient period of global warming, about 52 million years ago, through a new diet of to adopt nuts and seeds that enabled them to survive six months of winter darkness.”
- Miller K, Tietjen K, Beard KC (2023) Basal Primatomorpha colonized Ellesmere Island (Arctic Canada) during the hyperthermal conditions of the early Eocene climate optimum. PLoS ONE 18(1): e0280114. DOI: 10.1371/journal.pone.0280114