GeoPicture of the week: Giant Dragonfly fossil

This is a Cast of an original fossil of a Meganeuridae. If you’re scared of dragonflies, brace yourself for this: these extinct insects from the Carboniferous period measured up to 70 cm. They are the largest known species of flying insect.

Controversy has prevailed as to how insects of the Carboniferous period were able to grow so large, especially considering that there is a fixed upper limit placed on insects, based on the way oxygen is diffused through the insect’s body via its tracheal breathing system.