Fossil discoveries often help answer long-standing questions about how our modern world came to be. However, sometimes they only deepen the mystery, as a recent discovery of four new species of ancient insects in British Columbia and Washington state is showing.
The fossil species, recently discovered by paleontologists Bruce Archibald of Simon Fraser University and Vladimir Makarkin of the Russian Academy of Sciences, belong to a group of insects known as snake flies, which have now been shown to have lived in the region about a few years ago. 50 million years. The findings, published in Zootaxa, raise more questions about the evolutionary history of clearly elongated insects and why they live where they live today.
Snake flies are slender predatory insects that are native to the Northern Hemisphere and are notably absent from tropical regions. Scientists have traditionally believed that they require cold winters to trigger development in adults, restricting them almost exclusively to regions that experience frosty or colder winter days. However, the fossil sites where ancient species were found experienced a climate that does not fit this explanation.
“The average annual climate was moderate like Vancouver or Seattle today, but more importantly, with very mild winters with little to no frost days,” Archibald says. “We can see this by the presence of frost-intolerant plants like palm trees that live in these forests along with plants further north like spruce.”
The fossil sites where the ancient species were discovered span 1,000 kilometers of highlands from Driftwood Canyon in northwestern BC to the McAbee fossil site in southern BC, and to the town of Republic in northern Washington.
According to Archibald, paleontologists found species from two families of snake flies at these fossil sites, both of which were previously thought to require cold winters to survive. Each family seems to have independently adapted to the cold winters after these fossil species lived.
“We now know that early in their evolutionary history, snake flies lived in climates with very mild winters, so the question is why didn’t they maintain their ability to live in such regions? Why aren’t flies found today? snake in the tropics? “
Previous discoveries of fossil insects at these sites have shown connections to Europe, the Pacific coast of Russia, and even Australia.
Archibald emphasizes that understanding how life adapts to the climate by looking deeply into the past helps explain why species are distributed throughout the world today, and perhaps can help envision how further change in climate may affect that pattern.
“Such discoveries come up from these fossil sites all the time,” Archibald says. “They are an important part of our heritage.”
New fossil discovery shows 50 million-year connection between Canada and Australia
S. Bruce Archibald et al, Early Eocene (Raphidioptera) snake flies of western North America from the Okanagan Highlands and the Green River Formation, Zootaxa (2021). DOI: 10.11646 / zootaxa.4951.1.2
Provided by Simon Fraser University
Citation: Fossil Discovery Deepens Snakefly Mystery (2021, April 6) Retrieved April 6, 2021 from https://phys.org/news/2021-04-fossil-discovery-deepens-snakefly-mystery .html
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