The Eocene Period (cc. 43 to 66 million years ago) was a time of intense global warming, providing an important case study of how ecosystems react to changing climates. By examining fossils from the Ellesmere Island in Canada, a team of researchers led by the University of Kansas has found evidence of a warm, swamp-like environment around 52 million years ago, despite half the year experiencing Arctic harsh winter darkness. Based on fossil fragments of jaws and teeth, the experts identified two new species of primates – Ignacius dawsonae and Ignacius mckennai – that are our first known relatives from this ancient Arctic ecosystem.
Compared to primate species discovered in more southern regions, both of these species were unusually large (a common trait in northern mammals), and exhibited dental features suggesting a diet of hard food items, which was probably an adaptation for consuming tougher foods during long and dark Arctic winters in which softer meals were hard to find.
Although, during the early Eocene, North America’s lower latitudes were home to many other species of primates, only these two species were discovered in the North, adding to previous evidence that the ancient Arctic ecosystem experienced limited biodiversity compared to southern habitats. According to the researchers, while warmer temperatures allowed several organisms to migrate northward, these movements were most likely limited by factors such as the harsh Arctic winters they had to face once they reached those areas.
These findings could help scientists predict how ecosystems might react to contemporary climate change. “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 might unfold. The first primate-like fossils ever recovered north of Arctic Circle show that these tropically adapted mammals were able to colonize the Arctic during an ancient episode of global warming approximately 52 million years ago by adopting a new diet of nuts and seeds that enabled them to survive six months of winter darkness,” the authors concluded.
The study is published in the journal PLoS ONE.
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