Pterosaurs: dragons of the air
Permian: end of an era
The super continent of Pangaea, formed when all of the world’s continents became one single land mass, was fully assembled during the Permian. An effect of this was a massive reduction of shallow seas around the world. Consequently, there was a massive reduction in marine species diversity toward the end of the period. In the centre of the continent huge areas of desert with hypersaline seas formed, whereas ice caps developed at the poles. The planet was becoming quite inhospitable and the end of the Permian saw the extinction of 90 per cent of the world’s biota; possibly the greatest catastrophe in the Earth’s history. Despite this ‘end Permian extinction event’, evolution continued apace and reptilian life diversified through most of the period. Reptiles took to the air: the first gliders appeared.
Global reconstruction courtesy of Professor Ron Blakey, Northern Arizona University, Geology.
Permian gliding reptiles
Several small lizard-like reptiles took to the air during the Permian, evolving an ability to glide using a membrane attached to the side of the body and supported by fine bony struts. The membrane was not connected to the limbs, and therefore had very little control. Their flight may have been more akin to parachuting than gliding.
Fossils of these animals are rare and often incomplete, but examples have been found in County Durham in the United Kingdom, in Germany and on the island continent of Madagascar.
Coelurosauravus in mid-glide
Image courtesy of Graham Cripps, www.surfacevision.com
Three species of gliding reptile have been named: Coelurosauravus jaekeli, Coelurosauravus elevenis and Weigeltisaurus jaekeli, but the latter may belong in Coelurosauravus. These animals were no longer than about 40cm and had a flattened body and pointed skull. It was first thought that the gliding membrane in these animals was supported by elongate ribs, but a more detailed study revealed it to be supported by highly elongate bones embedded in the animal’s skin (called osteoderms). Thus, these animals had evolved a unique gliding structure not seen in any other group of gliding animals.