The term “air dinosaur” often brings to mind images of giant, winged reptiles soaring through prehistoric skies. While these creatures existed, they were not dinosaurs. The scientifically accurate term for these animals is pterosaurs, and they represent a distinct group of flying reptiles that coexisted with dinosaurs during the Mesozoic Era. Pterosaurs were the first vertebrates to achieve powered flight.
The Pterosaur Family
Pterosaurs were a diverse group, dominating the skies for over 150 million years. Their evolutionary journey began in the Late Triassic and ended in the same mass extinction that eliminated non-avian dinosaurs 66 million years ago. Though they are close relatives to dinosaurs, their evolutionary paths diverged, leading to fundamental differences in their skeletal structures, particularly in the hips.
The broader pterosaur group is divided into two main suborders. The earlier forms, known as “rhamphorhynchoids,” had long tails and jaws filled with teeth. These creatures, which flourished during the Triassic and Jurassic periods, were generally smaller than their later relatives.
A different group, the “pterodactyloids,” emerged in the Late Jurassic and came to dominate the Cretaceous skies. This suborder is characterized by shorter tails and, in many cases, a lack of teeth. It encompasses relatively small, duck-sized animals like Pterodactylus as well as the colossal Quetzalcoatlus, which boasted a wingspan comparable to that of a small airplane. At the end of the Cretaceous, several groups were still thriving, including the azhdarchids, pteranodontids, and nyctosaurids.
Anatomy of a Flying Reptile
The anatomy of a pterosaur was specialized for flight. Their most defining feature was their wings, which were different from those of birds or bats. A pterosaur’s wing consisted of a membrane of skin, muscle, and other tissues known as a patagium that stretched from a dramatically elongated fourth finger to their ankles, creating a large surface area for generating lift.
To make flight possible, their skeletons were lightweight. Pterosaur bones were hollow, with walls sometimes as thin as one millimeter, and filled with air sacs connected to their respiratory system. This structure provided the necessary strength for flight without adding prohibitive weight. An animal like Pteranodon, despite having a wingspan of over 20 feet, is estimated to have weighed only around 25 pounds.
Many pterosaurs, particularly within the pterodactyloid group, are known for the elaborate crests that adorned their skulls. These structures came in a wide array of shapes and sizes, from the tall, sail-like crest of Tupandactylus to the long, backward-pointing crest of Pteranodon. Scientists have proposed these crests may have been used for species recognition, as display structures to attract mates, or as rudders to help steer during flight.
Prehistoric Lifestyle and Diet
The shape of pterosaur teeth, or lack thereof, along with preserved stomach contents, indicates what these animals ate. Many species, especially those found in marine deposits, were skilled piscivores, hunting for fish over ancient oceans and lakes. Their long, often toothy snouts were well-suited for snatching slippery prey from the water’s surface.
Other pterosaurs adapted to different food sources. Smaller, agile species like Anurognathus had wide mouths and small, peg-like teeth, suggesting they were insectivores that hunted flying insects at dusk, much like modern bats. Some fossil discoveries indicate that certain pterosaurs may have been fruit eaters.
The largest pterosaurs, such as the massive Quetzalcoatlus, adopted a different strategy. With their immense size and long, stiff necks, it is believed they were terrestrial predators. They likely stalked across the prehistoric landscape on all fours, using their formidable beaks to hunt small animals, including dinosaur hatchlings.