Brief History of Pterosaurs

(Disclaimer: most information we have about dinosaurs is heavily fact-based speculation, and most of it cannot currently be fully confirmed, if at all, due to resources and the nature of fossils. A lot of knowledge can still be gathered though, even if we do not 100% know if it’s true. We are still learning and discovering and will continue to do so. The information found in this article is from years of me personally researching and learning about dinosaurs and prehistory. Because of this, no sources are cited but if you are interested I highly encourage you to do your own research!)

Pterosaurs are arguably one of the most recognizable dinosaurs. They show up in movies and tv shows and books and countless other things. But how did they live? What did they eat? When were they alive? What happened to them? Let’s find out

The name Pterosaur means winged lizard, and they were the first vertebrates to fly. They show up in the fossil record around 215 million years ago during the early Triassic and then went extinct in the late Cretaceous, thriving for almost all of the Mesozoic era. There are over 200 known species of Pterosaur, and two main groupings; the Rhamphorhynchoids and the Pterodactyloids. The Rhamphorhynchoids were smaller, had differentiated teeth and longer tails. On the other hand, Pterodactyloids were much bigger, with short tails and longer wrist bones, had larger, crested heads, and small, if any, teeth. A very well known Pterodactyloid is the Pterodactyl, as the name would suggest. But the two main factors that link their two families together are the wing makeup and relatively unknown evolution. 

From the early Triassic to the first half of the Cretaceous, Rhamphorhynchoids were the majority of Pterosaurs that existed. But when bird appeared and joined the Pterosaurs in the sky, they had to adapt to more evolutionary niches in order to survive. This lead to them growing bigger and bigger until they reached wingspans of up to 12 meters (40 feet) -and as time went on, they became even more specialized for flying. Their bones became even lighter and they most likely developed unidirectional airflow, much like birds, to better breathe while flying. Another element that aided them was the structure of their wings. Three layers made up the membrane of the wing, which contained fibrous cords, muscles, and blood vessels. Because of the muscles in their wings, they could most likely move flaps of wing to affect direction, elevation, speed and more, much like modern day planes. These wings were attached at the ankle through shoulder and extended the arm and elongated finger for which the first discovered Pterosaur was named – Ptero meaning wing or winged and dactyl meaning finger. But not all Pterosaurs were flying all the time. Based on pelvis shape, shoulder makeup, and general bone structure, they most likely could walk around like bats do today.

One problem that has come up is that we currently don’t know exactly how Pterosaurs evolved. Because of their incredibly light bones, they don’t fossilize well thus making it difficult to determine where exactly they came from. However, there are a couple of theories regarding how they might have evolved. The first two theories both involve Pterosaurs ancestors living in trees. The first one, the arboreal leaping theory, is that the early ancestors would move around to get food and shelter and just to get places by jumping from branch to branch. Over time, they eventually developed a thin membrane between their legs (kind of like a sugar glider) and that membrane evolved into Pterosaurs’ wings. The second theory, the arboreal parachute model, is quite similar except they would fall downwards to get away from danger and developed the membrane to move more efficiently. The third, and currently most likely, theory on how Pterosaurs evolved doesn’t have to do with trees at all.

The most widely accepted theory on how Pterosaurs evolved, called the ground up theory, states that they could have started living on the ground and jumping up to catch their prey. They then slowly developed a membrane between their legs that grew into full wings capable of flight to catch prey. The reason this theory is most viable is due to a bipedal dinosaur called Scleromochlus that resided in what is now modern day Scotland. The reason for linking the two seemingly unrelated creatures is due to bone structure and diet. Pterosaurs contain a unique mix of features that create their signature look, and aren’t commonly found in other dinosaurs. Scleromochlus is an exception. Both creatures have a square pelvis, long shoulder blades, light but large head and very small leg bones. And if Scleromochlus isn’t Pterosaurs ancestor, something very similar probably is. 

Quetzalcoatlus, early Cretaceous, standing height of 20ft and wingspan of 35ft, average of 500lbs

Anurognathus, late Jurassic, had a wingspan of 14 in. and body of 3.5 in. estimated to weigh an ounce

Leave a Reply

Your email address will not be published. Required fields are marked *