A research team led by SFU discovers how dragonfly fossil relatives are misclassified due to their striking resemblance
Credit: Copyright Zootaxa, used with permission.
For more than 150 years, scientists have incorrectly classified a group of fossil insects as damselflies, the common cousins of dragonflies that fly around wetlands that eat mosquitoes. While they are strikingly similar, these fossils have oddly shaped heads, which researchers have always attributed to the distortion resulting from the fossilization process.
Now, however, a team of researchers led by Simon Fraser University (SFU) paleontologist Bruce Archibald has discovered that they are not bloody animals at all, but represent a major new insect group closely related to them.
Results published today at Zotaxa, Shows that the distinctive shape of the insect’s non-protruding round eyes, located near the head, are the hallmarks of a sub-salad associated with worms and dragonflies that researchers have named Cephalozygoptera.
“When we started to find these fossils in British Columbia and Washington state, we also thought at first that they must be bloody animals,” Archibald says.
Upon closer examination, however, the team noticed that it resembled a fossil that German paleontologist Hermann Hagen wrote about in 1858. Hagen set a precedent for linking the fossil to the suborder despite its different head shape, which does not match the damsil fly at all.
Damselflies have short, broad heads and eyes that are clearly protruding to each side. But Hagen’s fossil has an oddly round head and eyes. But I assumed that this difference was erratic due to distortion during ossification.
“Paleontologists have written since Hagen that these were animals with deformed heads,” Archibald says. “A few of them hesitated, but they still appointed them to the secondary level.”
The team led by SFU, including Robert Canings of the Museum of Royal British Columbia, Robert Erickson and Seth Bibi of Brigham Young University and Rolf Matthews of SFU, examined 162 years of scientific papers and discovered that many similar specimens had been found since Hagen’s time.
They had an eureka moment when they realized that the strange heads of their new fossil were in fact their true form.
The researchers used the shape of the fossil’s defining head to name the new suborder Cephalozygoptera, meaning “damselfly head.”
The oldest known species of Cephalozygoptera lived among dinosaurs in the Cretaceous period in China, and the last time they were known to exist was about 10 million years ago in France and Spain.
“They were important elements in the wetland food webs of ancient British Columbia and Washington about 50 million years ago, after the extinction of the dinosaurs,” Archibald says. “Why they refused and became extinct remains a mystery.”
The team named 16 new species of Cephalozygoptera. Some fossils have been found on the traditional land of the Colville Indian tribe in northern Washington, so Archibald and his colleagues teamed up with the tribal elders to name a new family of them. They named the family “Whetwhetaksidae,” from the word “whtwhetaks,” which means dragonfly-like insects in the language of the Colville people.
Archibald spent 30 years combing the fossil-rich sediments of southern British Columbia and inner northern Washington. So far, in collaboration with others, he has discovered and discovered more than 80 new species from the region.
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