Pterosaurs were flying reptiles that lived during the Mesozoic Era, from about 220 million years ago to 66 million years ago. They were the first vertebrates to evolve powered flight, and they came in a wide variety of shapes and sizes. Some pterosaurs were small and lightweight, with wingspans of just a few feet. Others were much larger, with wingspans of up to 30 feet. Pterosaurs had a lightweight skeleton made of hollow bones, which helped them to fly. A Flying Pterosaur Sticker.