New fossil discovery in Canada raises questions about ancient animal dispersal and climate in the Northern Hemisphere

Simon Fraser University researchers are investigating a recent fossil discovery near Princeton, B.C., which has prompted inquiries into the historical dispersal of animals and plants across the Northern Hemisphere around 50 million years ago. The findings suggest that brief periods of global warming might have played a role in this process.

The fossil, belonging to the extinct ant species Titanomyrma, was unearthed by Princeton resident Beverly Burlingame and provided to the scientists through the local museum. It is the first Canadian specimen of this ant, and surprisingly, the largest species possessed a massive size, comparable to a wren in body mass and boasting a wingspan of half a foot.

Paleontologists from SFU, including Bruce Archibald and Rolf Mathewes, collaborated with Arvid Aase from Fossil Butte National Monument in Wyoming to publish their research on the fossil in The Canadian Entomologist.

A decade earlier, Archibald and his colleagues stumbled upon a gigantic Titanomyrma fossil from Wyoming in a museum drawer in Denver. “The age of this ant, along with the new discovery from British Columbia, closely aligns with other Titanomyrma fossils found in Germany and England,” explains Archibald. “This raises questions about how these ancient insects managed to travel between continents and appear on both sides of the Atlantic around the same time.”

During that era, Europe and North America were connected by land in the Arctic region, as the North Atlantic hadn’t fully separated them due to continental drift. However, the researchers wonder if the far-northern climate at the time was suitable for the ants’ migration.

The scientists observed that the regions where these ants thrived in Wyoming and Europe had hot climates in ancient times. They also discovered a correlation between large queen ants and hot climates among present-day ants. However, this presents a conundrum, as although the ancient Arctic had a milder climate compared to today, it still wouldn’t have been warm enough to facilitate the passage of Titanomyrma.

The giant fossil queen ant Titanomyrma, recently discovered in the Allenby Formation near Princeton, British Columbia, the first of its kind in Canada. Credit: Bruce Archibald

New findings build on earlier research

In 2011, the researchers proposed a possible explanation for the phenomenon: brief periods of global warming known as “hyperthermals” might have created favorable conditions for Titanomyrma to cross between continents.

Based on this hypothesis, they initially predicted that Titanomyrma would not be found in the ancient temperate Canadian uplands, as the climate there would have been cooler than what Titanomyrma required. However, the recent discovery of a Titanomyrma fossil in Canada complicates the story. The fossil was distorted during fossilization, making it challenging to determine its true size. It could have been gigantic like some of the largest Titanomyrma queens, or it could have been smaller.

This discovery raises intriguing questions: If the Canadian specimen belonged to a smaller species, does that imply adaptation to cooler climates, contradicting the earlier prediction? Alternatively, if it was indeed gigantic, does it challenge the researchers’ understanding of the climatic tolerance and migration of giant ants across the Arctic?

Archibald emphasizes that this research contributes to our understanding of the formation of British Columbia’s animal and plant communities in vastly different climates. By comprehending how life dispersed in the northern continents during a distinct climatic era 50 million years ago, we gain insights into current patterns of animal and plant distribution.

Moreover, studying Titanomyrma may provide insights into how global warming could impact future changes in the distribution of life. Archibald concludes by acknowledging the need for further fossil discoveries to refine our understanding of Titanomyrma’s ecology and the ancient dispersal of life. Until then, the mysteries surrounding Titanomyrma and its migration persist.

Source: Simon Fraser University

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