Before dinosaurs evolved, around 300 million years ago, the world was a swampy, green landscape. During this time, giant dragonfly-like insects known as griffinflies dominated the skies. With wingspans reaching up to 71 centimeters, these massive insects would have blocked out the Sun as they flew by.
What did griffinflies look like, and where did they live?
Ben Price, Principal Curator of part of our insect collection, explains that the body structure of dragonflies has remained largely unchanged for 350 million years, except for a reduction in size. So, if you picture a regular dragonfly, but much larger, you’re on the right track.
Given their immense wingspan, it’s unlikely that griffinflies could fly through dense forests. They probably lived in open wetlands and marshes.
Why did griffinflies grow so large?
In the early stages of a dragonfly’s life, it lives as a larva in water and absorbs oxygen through gills. As adults, dragonflies take in oxygen through small openings called spiracles.
One theory suggests that griffinflies grew so large due to higher oxygen levels in the atmosphere 300 million years ago. This would have allowed them to absorb enough oxygen through their spiracles, despite their large size.
Another theory posits that griffinflies grew bigger because there were no aerial predators to hunt them. However, as birds evolved from dinosaurs and began preying on them, griffinflies had to become smaller and faster to survive.
The evolution of wings in insects
While wings evolved multiple times in vertebrates—such as in bats, birds, and pterosaurs—they may have evolved only once in insects.
Wings provide a significant survival advantage: they allow insects to cross barriers like water, access more food, and escape predators.
The oldest known winged insect is a griffinfly called Delitzschala bitterfeldensis, which lived 325 million years ago. This species belongs to the now-extinct order Palaeodictyoptera, which included over 30 families.
The origin of insect wings remains a topic of debate, with competing theories on how they evolved. Some researchers believe wings may have developed from the gills of aquatic insect larvae, since freshwater insects are the oldest evolutionary branch. A more recent theory suggests that insect wings evolved from the legs of their crustacean ancestors.
