The “monster dragonfly” is a mainstay of prehistoric movies, games and cartoons. But that idea is wrong for two reasons: it was neither a monster, nor a dragonfly.

(I say that, but as per my bug posts, here’s a link to the image to spare the squeamish.)

With its 70cm (28 inch) wingspan, Meganeuropsis was indeed big, and weighed as much as a crow. It also beat its relative and previous record holder, Meganeura, by 5cm (2 inches). But for reasons I’ll explain later, it wouldn’t have bothered you too much. It’s also not even a dragonfly.

Both it and Meganeura go by the much cooler “griffinfly” moniker, because they had a different wing structure to modern-day dragonflies, and the males didn’t have any, er, secondary genitalia. I searched high and low for why they’re called griffinflies, and all I could find was a comment by palaentologist Dan Chure about “griffen” being German for “attack”. Even he wasn’t sure, though.

Or it could just be because griffin = like a dragon but not.
Image by Gordon Johnson from Pixabay

I realise that “attack fly” still sounds quite bad, so here are six reasons not to worry about it.

1. It’s dead.

Despite etomologist Robin Tillyard hoping to resurrect it via mystic (yes), Meganeuropsis is long gone.

It died out around 250 million years ago in the Permian period, when Earth was still a giant supercontinent called Pangaea.

Image by Massimo Pietrobon, via Wikimedia Commons.

This was even before the dinosaurs were on the scene, or any reptiles, birds or mammals took to the air. But this big insect went out big.

If you thought the extinction of the dinosaurs was bad, that was just the low-budget sequel. According to Grimaldi and Engel, the mass extinction at the end of the Permian was “the most traumatic cataclysm Earth ever experienced”, also known as the Great Dying. About 70% of life on land and 95% of marine life was wiped out, the prime suspects being a comet strike, volcanic activity, and lack of oxygen (anoxia) in the seas. Possibly all at the same time.

And in case you were worried about Meganeuropsis returning for a sequel:

2. None of today’s insects could reach its size.


Sorry to add that frightening adverb, but we’re not 100% sure how Meganeuropsis and its buddies grew so big. One reason might be the amount of oxygen in the air, so as long as that doesn’t shoot up, its present day buddies should stay pretty small.

…relatively speaking. This is the largest dragonfly in the world today, Megaloprepus coerulatus, with a 19cm / 7.4 inch wingspan.
Image by Emőke Dénes, via Wikimedia Commons.

Why is this the case? Instead of a heaving set of lungs, insects breathe through holes called spiracles, and these lead into small, trachea-like tunnels in their bodies. It’s at the end of said tunnels that oxygen is absorbed into the cells, so the larger the insect, the longer the tunnels, and the further the oxygen needs to travel.

On Earth today, the air is about 21% oxygen. Back in Meganeuropsis‘ time it was around 35%. With 15% more of it in the atmosphere, an insect could grow bigger while still getting enough oxygen down its tubes.

Another oxygen-related theory is that it gave Meganeuropsis a growth-boost when it was moulting.

Speaking of moulting, how do we know the Meganeuropsis we’ve found were full size? Couldn’t they be youngsters, with gargantuan parents yet to be discovered? Nope, because according to Chure, they have wings.

While not direct ancestors, griffinflies have a similar biology to dragonflies, and once they get their wings, they’ve officially left childhood. (Or nymph-hood, to be precise.)

Oxygen isn’t the full story either. Although levels dropped at the end of the Permian, they started rising again in the Jurassic, and this time the insects didn’t grow gigantic again. Why? This brings me to my next point:

3. It couldn’t survive today.

It was probably the top aerial predator of its time. Unfortunately, big isn’t always better.

For one thing, today’s air would be far too thin. Meganeuropsis would have trouble getting enough oxygen to live, let alone for any high energy aerobatics while catching prey.

For another, it would be dish of the day for the multitudes of birds and bats that have since invaded our skies.

But to play devil’s advocate, even if it could survive today:

4. You’d probably see it coming.

Not just because of its size, but because it couldn’t really ambush you.

It most likely hunted in open plains and wetlands, and went for other insects, amphibians, even fish. Either way, you’d still be able to escape, because:

5. You could probably outrun it.

Modern dragonflies have been (somewhat dubiously) clocked at over 48kph/30mph, and they both bend and twist the outer part of their wings during flight.

“On the wing”. An Australian emperor dragonfly, Anax papuensis, by Paul Baulfe.

For a while we didn’t even think Meganeuropsis could do that, and that its massive wings restricted it to gliding instead. Although they were sturdy – literally the only parts that survived hundreds of millions of years – they had a much simpler structure. Dr. Roy J. Beckemeyer, a former aeronautical engineer, thinks Meganeuropsis would have gradually twisted its whole wing when flying rather than just the outer part, and as a result, would have flown more slowly than its modern relatives.

So we’re still finding out about it. In fact for all we know:

6. It might have been an anomaly.

Fossilisation isn’t kind to anyone, especially insects with delicate bodies. What’s more, larger animals are both easier to find and have more material to be preserved, so Meganeuropsis could just be the top end of the insect scale. Imagine if a future palaeontologist dug up a blue whale and assumed most mammals of our time were that size. They would either be disappointed or relieved at the truth.

That said, I’m all for bringing it back to deal with our mosquitoes. If only the mystic idea had worked…

Meganeuropsis Fact File

Latin: Meganeuropsis (permiana/americana)

I couldn’t track down the official meaning of this either, but “opsis” in Greek apparently means likeness or resemblance. Meganeura means “large nerve”, so “looks like Meganeura” is a possibility, if an uninspired one. You’d think the biggest insect ever found would have a more sensational name.

Helpfully, the permiana and americana species names – both permiana according to Chure – mean “from the Permian” and “from America”, respectively.

What? Large prehistoric relative of the modern dragonfly, and the largest insect ever recorded. It’s technically known as a griffinfly.

First recorded? By Frank D. Carpenter, who discovered Meganeuropsis permiana in the Elmo Formation of Kansas, USA in 1939, and Meganeuropsis americana in the Wellington Formation of Oklahoma in 1947.

Where? Around 300-248 million years ago in the Permian period, flitting about in the USA, or back then, a tropical coastal wetland.

How big? It had a wingspan of 70cm / 28 inches.

Diet? Most likely other insects, as well as small fish and amphibians.

Social behaviour? Not a clue. We’ve only found a few wing fragments so far and their bodies are mostly guesswork, let alone any kind of social structure or behaviour.

Just to prove I’m not fibbing:

The Age of Oxygen (400 million to 290 million years ago)“. No date. Forces of Change/Smithsonian Environmental Research Center.

Carpenter, Frank M. 1939. “The Lower Permian Insects of Kansas. Part 8: Additional Megasecoptera, Protodonata, Odonata, Homoptera, Psocoptera, Protelytroptera, Plectoptera, and Protoperlaria“. Proceedings of the American Academy of Arts and Sciences 73(3):29-70.

Carpenter, F.M. 1943. “Studies on Carboniferous insects from Commentry, France; Part I. Introduction and families Protagriidae, Meganeuridae, and Campylopteridae”. GSA Bulletin 54 (4): 527–554.

Carpenter, Frank M. 1947. “Lower Permian Insects from Oklahoma. Part 1. Introduction and the Orders Megasecoptera, Protodonata, and Odonata“. Proceedings of the American Academy of Arts and Sciences 76(2):25-54.

Carpenter, F.M., and Burnham, L. 1985. “The geological record of insects“. Annual Review of Earth and Planetary Sciences 13:2917-314.

Chure, Dan. 2012. “The magnificent, giant (and unfortunately extinct) griffenflies, both earthly and extra-dimensional”. Land of the Dead.

Dodgson, Linda. 2017. “This myth people keep quoting about how bees shouldn’t be able to fly is scientifically incorrect — here’s why“. Business Insider.

Editors of Encyclopaedia Britannica. No date. “Permian Extinction“.

Fossilworks. No date. “Meganeuropsis permiana Carpenter 1939 (griffinfly)”.

Fountain, Henry. 2004. “When giants had wings and six legs“. New York Times.

Garrouste, Romain, and Nel, André. 2019. “Are the Paleozoic era’s giant dragonflies still among us?” The Conversation.

Grimaldi, David, and Engel, Michael S. 2005. “Evolution of the insects“. Cambridge University Press.

Hadley, Debbie. 2019. “Overview of the biggest bugs that ever lived“.

Hoffman, Hillel J. No date. “The Permian Extinction: When life nearly came to an end“. National Geographic.

Holland, Jennifer S. 2020. “Eat, fly, love, die: Dragonflies’ brief but glorious life on the wing“. National Wildlife Federation.

Langley, Liz. 2016. “What was the biggest insect that ever lived?” National Geographic.

The largest complete insect wing ever found“. 2007. Harvard Magazine.

Low, Tim. 2017. “Dragonflies: global masters of the sky“. Australian Geographic.

Manger, Walter L. No date. “Carboniferous Period“.

May, Michael L. 2019. “Odonata: Who they are and what they have done for us lately: Classification and ecosystem services of dragonflies“. Insects 10(13):62.

Mitchell, Forest L, and Lasswell, James L. 1955. “A dazzle of dragonflies“. Texas A&M University Press.

Monsters of the skies: giant beasts that ruled the air“. 2009. New Scientist.

Nel, André et al. 2018. “Paleozoic giant dragonflies were hawker predators”. Scientific Reports 8:12141.

Prokop, Jakub, and Nel, André. 2010. “New griffenfly, Bohemiatupus elegans from the Late Carboniferous of western Bohemia in the Czech Republic (Odonatoptera: Meganisoptera: Meganeuridae)“. Annales de la Société entomologique de France (N.S.), 46(1-2):183-188.

Rajabi, H. et al. 2017. “Dragonfly wing nodus: A one-way hinge contributing to the asymmetric wing deformation“. Acta Biomaterialia 60:330-338.

Rajabi, H. et al. 2020. “Insect wing damage: causes, consequences and compensatory mechanisms“. Journal of Experimental Biology 223(9):jeb215194.

Than, Ker. 2012. “Giant bugs eaten out of existence by first birds?” National Geographic.