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Don't worry. This isn't an announcement of a new invasion from elsewhere, but a leap into the past in the Paleozoic: the time of giant insects, 100 million years before the dinosaurs, during which insects also had their T-Rex: Carboniferous and Permian giant dragonflies that terrorised the skies of those times, sometimes call "griffenflies"). A short trip back in time to a kind of another Earth in search of insects that were already major actors of the ecosystems.

This unique specimen in the world is a giant dragonfly that lived 300 million years ago in the huge equatorial warm forests that at the time covered the center of France. It was almost 40 cm long and 70 cm wingspan. It is one of the largest known insects.

During the Carboniferous (from 360 to 299 million years ago), other insects were also very large, such as cockroaches (Dictyoptera) and Palaeodictyoptera. This gigantism has long been explained by the high percentage of oxygen in the air (twice the current level, i.e., nearly 40%) which would have favoured the physiology of flight during this period. Explanations based on ecological factors more related to the absence of flying predatory vertebrates at this time would explain these large insect sizes. A combination of both phenomena should be considered.

For many millions of years, during Carboniferous, large quantities of plant debris accumulated in shallow waters. Their burial, protected from the air by the sediments that contained them, contributed to the formation of very fossiliferous layers of coals.

Meganeura was described and named by Charles Brongniart in 1885, shortly after its discovery. This dragonfly from the depths of time is the emblem of the city of Commentry in the Auvergne region, the former mining town where it was found. It was long emblematic of the giant insects of the Palaeozoic, remaining the largest known insect until the discovery of a Meganeuridae in the United States in the middle of the 20th century, which are a few centimeters larger.

Read more at: https://phys.org/news/2018-09-paleozoic-era-giant-dragonflies.html

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