Pteranodon is a genus of pterosaurs which includes some of the largest known flying reptiles with wing spans over six metres (20ft). They existed during the late cretaceous geological period of North America. They were
of light built and their forelimbs evolved into membranous wings or patagia. First three fingers were short, hooked and probably used for clinging to rocks. Fourth finger was greatly elongated to support the edge of patagium. Fifth finger was lost.