New insect group discovered after scientists solve 150-year-old mystery

BURNABY, British Columbia — A group of fossilized insects have mystified scientists for over 150 years. During that time, no one had been quite sure what to make of these fossils due to the odd shape of their heads. Scientists had always just classified them as damselflies, closely related cousins of dragonflies which reside in wetlands and eat mosquitoes. Now, researchers at Simon Fraser University have discovered the fossils aren’t damselflies after all. Instead, these fossils represent an entirely new insect group.

The team at SFU say the fossils’ odd heads, characterized by non-protruding, rounded eyes, are a defining feature of a suborder related to damselflies and dragonflies. Study authors have decided to name this new insect group Cephalozygoptera (“head damselfly”).

“When we began finding these fossils in British Columbia and Washington State, we also thought at first they must be damselflies,” says research leader and SFU paleontologist Bruce Archibald in a university release.

insect wing fossil
Wings of the new species Okanagrion threadgillae, from the Republic fossil site in northern Washington, a damselfly-like insect of the new suborder Cephalozygoptera. (Copyright Zootaxa, used by permission.)

Upon closer inspection, however, Archibald noticed that the heads look a lot like fossils described by German paleontologist Hermann Hagen way back in 1858. Traditional damselflies have short and wide heads with far-apart eyes. Hagen’s fossil, though, had a rounded head and eyes. At the time, Hagen dismissed the cranial differences as “distortions caused during fossilization.”

“Paleontologists since Hagen had written that these were damselflies with distorted heads,” Archibald explains. “A few hesitated, but still assigned them to the damselfly suborder.”

After his Hagen epiphany, Archibald and the rest of his team searched through 162 years worth of scientific papers. This extensive effort eventually bore fruit; many fossils resembling what Hagen had found in 1858 have been discovered since.

These discoveries led researchers to conclude that the rounded head of these fossils wasn’t a distortion, but the true shape of these insects’ heads.

Researchers estimate the oldest Cephalozygoptera lived in China during the time of dinosaurs. The last are believed to have lived in France and Spain around 10 million years ago. Overall, the research team has named 16 new varieties of Cephalozygoptera.

“They were important elements in food webs of wetlands in ancient British Columbia and Washington about 50 million years ago, after the extinction of the dinosaurs,” Archibald comments. “Why they declined and went extinct remains a mystery.”

The study is published in Zootaxa.