Pterosauria refers to a group of flying reptiles that lived during the Mesozoic Era, alongside the dinosaurs. They are not dinosaurs themselves but are closely related. Pterosaurs had a wide range of sizes, from small, sparrow-sized creatures to large ones with wingspans exceeding 30 feet. Their wings were formed by a membrane of skin and muscle stretched between an elongated fourth finger and their body. Pterosaurs are known for their unique adaptations for flight, including lightweight bones and a beak-like jaw. They primarily fed on fish and other small animals, using their keen eyesight to spot prey from the air. Fossils of pterosaurs have been found on every continent, showcasing their diverse habitats and lifestyles during their time on Earth.