The Shed

The Shed
The Shed

Sunday, June 17, 2012

SOMETHING DEAD FROM THE SHED - Meganeueropsis permiana

Hello again everybody Its me, Jack, back from a trip to me old haunts in White Chapel. I've a smile on my face, a song in my heart, blood stains on my neck tie and surgical steel in my carryall.

A man has to touch base with his roots, from time to time.

Today on "Something Dead from the Shed" we'll be touching on the subject of giant dragonflies. No, not just a big bug from the back yard, but specimens larger than some surveillance drones. (Would have been hard times for Jackie if the coppers had drones in their bag o' tricks back in 1888, hey?)

We actually had a pair of these creatures here in the garden for about 3 - 4 minutes and as a group you can't find one that's any deader than the Meganeuropta so what better subject for my little essay?


As for the pair we had here momentarily, Mac had taken a day trip to the Carboniferous and came back with a great whacking box that was making suspicious rattling noises. He opened it up and out popped a pair of dragonflies, wings as wide as your arm is long! They flapped around awkwardly for about twenty seconds before auguring into the sweet corn like economy passenger jets into a Florida swamp.

"Mac! You silly bastid they can't breath!" I remember Farm Girl scolding the old coot, "The oxygen content was over 40% higher back when they were around! You take them back right now!"

"Arrgghh", Mac replied "They're bugs! Let 'em flop a bit we can add them to the compost."

"You..." said Farm Girl, "take them back now or you'll be polishin' your own dibble until the next ice age!"

The argument must have struck home because Mac had the feebly wriggling insects back in the box before you could say "unpolished dibble" which really is relatively easy to say. He disappeared with the "pop" that announces wormhole manipulation and was back five minutes later with an empty box, a bloody thumb and a surly manner.

"Bastid bit me. There's gratitude for ya!" 

A nasty infection ensued of course, nothing screws with the immune system like 300,000,000 year old bacteria. But eventually he healed right enough, all digits intact and only a nasty scar and one more thing to grumble about to show that damage had ever been done.

But enough Shed lore! Lets talk Meganeuropta!


When enormous dragonflies ruled the sky:

Life was never easy for small amphibians or average sized flying insects during the late Carboniferous and early Permian periods of the Paleozoic Era. As though the day to day requirement to feed and reproduce were not enough to worry about, the diminutive amphibian had to avoid hungry fishes when in the water, and apex predators like the therapsids (Titanophoneus as just one example) and pelycosaurs (Dimetrodon and kin) when on land. Large, hungry amphibians like Sclerocephalus were a danger whichever environment the tiny creature happened to occupy.

You would think that would be enough to contend with, and since pterosaurs were millions of years in the future as were predatory birds like herons, hawks and pelicans the little creature would be safe from above.

Not so. For, hovering aloft like the Apache attack helicopters they resemble were the gigantic dragonflies Meganeuropsis permiana.

Leave the fly swatter in the closet:

Probably the largest flying insect that ever lived, fossils of Meganeuropsis permiana have been discovered that have a wing span of just under 30 inches and a total body length of 17 inches. These were the largest creatures flying in the Carboniferous and Permian skies and like their smaller close relatives the modern dragonflies were voracious predators. Or perhaps more accurately, even more so.

The food required to produce the energy to keep this huge body aloft must have kept Meganeuropsis perpetually on the hunt. Modern dragonflies will attack tiny tadpoles and newly hatched fry; we can easily envision Meganeuropsis swooping down on anything up to chipmunk size that came to its attention. And of course, anything flying that was smaller than Meganeuropsis was fair game.

Raising a lot of questions:

Today there are no flying insects even close to the size of this ancient predator, for which we should probably be thankful. There is a school of thought that says that this creature should not have been able to fly at all.

The answer to how it did so lies more in the geography, climate and atmosphere of the Carboniferous and Permian periods than in the morphology of the huge insect itself. To simplify enormously; during most of the Carboniferous and Permian periods there existed one super continent, Pangaea, containing almost all of the earths land mass. An explosion of flora, all utilizing the photosynthetic process produced immense amounts of oxygen while binding enormous quantities of carbon dioxide. Over time this actually shifted the proportions of the earth’s gases.

Today, our atmosphere contains about 21% oxygen. It is estimated that Carboniferous-Permian atmospheres contained at least 30% and possibly as much as 35% oxygen, with a corresponding dip in the amount of free carbon dioxide. This, so the theory goes, permitted Meganeuropsis and its kin to breath efficiently, even though they do so through trachea and not through lungs and a circulatory system as we do. This would have kept the creatures oxygenated enough to fly.

Why did they go extinct?

On one level, this question is easily answered. The end of the Permian period was marked by one of the greatest mass extinctions ever known on our planet. Nearly everything that lived, died. That Meganeuropsis was among the casualties is no surprise. The deeper question of what caused the P/T extinction is a subject for intense debate, although once again it seems that massive impact from an extraterrestrial body may be to blame.

Whatever triggered the event of one fact we can be certain. The oxygen level of earths atmosphere, either as a by product of the extinction event itself or by some other mechanism that we do not as yet understand dropped precipitously. This alone would have sealed the fate of the great dragonflies forever.

And that's about that for today's Shedly dose of big bugs. Your pal Jack signing off; thanks for visiting us at "Something Dead from the Shed!"

[Editors note: Not so fast! The University of Arizona did an interesting experiment in which they raised modern dragonflies in an atmosphere approximating that which prevailed in the Carboniferous - early Permian. The result in a single generation was an average increase in size and weight of fifteen percent per dragonfly. 

Next time you are targeting that medium sized buzzing thing circling over your garden, before you squeeze the trigger make certain its a government drone you are ranging in on, and not some innocent escapee from UA!]






Alexandra Heep said...

Wow. That's some creepy stuff. I am not too fond of insects in the first place ... said...

And I have the audacity to complain about mosquitoes??? Cool stuff!