They flew with their fingers. They walked on their wings. Some were gigantic, while others could fit in the palm of a hand. Millions of years ago, the skies were ruled by pterosaurs, the first animals with backbones to fly under their own power.

Dr. Mark Norell, curator and chair of the Museum's Paleontology Division, oversaw this exhibition with Dr. Alexander Kellner of Museu Nacional in Rio de Janiero.

Neither birds nor bats, pterosaurs were reptiles, close cousins of dinosaurs who evolved on a separate branch of the reptile family tree.

Many animals can glide through the air, but pterosaurs, birds, and bats are the only vertebrates that evolved for powered flight.

Few pterosaurs lived close to the places where fossils tend to form. Their fragile bones preserved poorly, so pterosaur fossils are frequently incomplete.