Ask AI: Are pterosaurs/pterodactyls dinosaurs? Why or why not?

No, pterosaurs or pterodactyls are not considered dinosaurs. While they did live during the same period as dinosaurs, they are classified differently due to key physiological differences. Pterosaurs are part of a distinct group of reptiles called 'Pterosauria', considered to be close relatives of dinosaurs. Key differences include their wings and their bone structure. Unlike dinosaurs, pterosaurs were capable of powered flight. Their wings were formed by a membrane of skin, muscle, and other tissues stretching from the ankles to a dramatically lengthened fourth finger. Another distinction is their bone structure. Pterosaurs had hollow bones, contributed to their ability to fly. Most dinosaurs, in contrast, did not have this feature. So even though pterosaurs are commonly associated with dinosaurs, from a classification perspective, they are not considered to be dinosaurs. They are a distinct branch of the reptile family tree, just like dinosaurs are.