Ornithodira is a clade that includes two major groups: pterosaurs and dinosaurs. These reptiles are characterized by their unique adaptations for flight and bipedal locomotion. Ornithodira first appeared during the late Triassic period and thrived throughout the Mesozoic era. The key features of Ornithodira include lightweight bones, elongated limbs, and specialized joints that allowed for efficient movement. Pterosaurs, the flying members of this group, developed wings formed by a membrane of skin, while dinosaurs evolved into various forms, including both herbivorous and carnivorous species.