Science & Technology

Old News: Taking Dinosaurs to new Heights

In this issue of Old News, I’m going to talk about some of the most iconic orders of dinosaurs, the Pterosauria. The Pterosauria, such as the Pterodactylus and Pterandon, were the family of flying dinosaurs that roamed the entire planet from the late Triassic until the end of the Cretaceous. One common misconception about the Pterosauria is that modern day birds are directly descended from them, but birds are actually descended from smaller terrestrial dinosaurs. Just imagine if modern day birds were indeed descended from the larger members of the Pterosauria family, like the Quetzalcoatlus species which had a wing span of around eleven or twelve meters. The bald eagle, one of today’s largest flying birds, has a maximum wingspan of around 2.3 meters.

The term dinosaur technically does not apply to any of the flying species. The term dinosaur scientifically only applies to reptiles which were descended from the common ancestor groups Saurischia, which all carnivorous dinosaurs are descended from, and Ornithischia, which herbivores are descended from. The Pterosauria, along with many types of marine reptiles from the era of the dinosaurs, are excluded from these groups.

The Pterosauria had a wide range of sizes, with wingspans ranging from eleven inches to over eight feet, but for the most part they shared similar features during specific eras. The wings of the Pterosauria consisted of a membrane of leathery skin and muscle stretched over their bones and connecting their ankles to their hands. Early species had long tails which were likely not useful for flight and which were greatly reduced as they evolved. Some species even had fuzzy coat or pycnofibers, which closely resembled mammalian fur. The family of Pterosauria were the first known vertebrates to develop flight. Earlier species possessed the ability to glide from point to point like the flying squirrel, but not powered flight.

All of the Pterosauria were carnivorous, like modern day birds of prey. Most had long beaks and while some had teeth, most were toothless. Their forelimbs were also usable for feeding, as they hold prey steady once caught or even tear it apart. Typically the terrestrial fliers ate small prey, eggs, and scavenged carcasses. Some species lived on the or near the water, and ate fish, squid and various shellfish. Studies suggest that they could sit on the water the way that modern day ducks do, except that their beaks would have sat close to or under the water. This is thought to have led to the drowning deaths of many juvenile Pterosauria, as they did not possess the muscular endurance to keep lifting off from the water.

I’ve loved the idea of flying dinosaurs since I saw Jurassic Park 3. Yes, I know it’s a horrible movie, but it has its shining moments. The Pteranodon was the greatest example of a flying dinosaur, and lived during the Upper Cretaceous period between 75 and 85 million years ago. It shared the common appearance of the flying dinosaurs, with a needle shaped beak and large crest on the back of its head to counterbalance the weight of the beak during flight. The Pteranodon was also toothless, leading to its name, which means wing and toothless. Its hands were at the “elbow” of its wings, with an extended fourth finger. This finger held one side of the Pteranodon’s wing, with the other being attached to its ankle.

At the other end of the spectrum was the Rhamphorhynchus, which was one of, if not the, strangest flier ever. Its beak was very distinctive; it had an upwardly-curved tip and needle like teeth which interlocked when closed, giving it a very menacing appearance. These needles were designed specifically to pierce fish. Its body was covered with a furry coat of pycnofibers, and it had a long tail with a frill on the end. Its wingspan was around six feet, but unlike other members of its family it had a very short neck. This suggests that the Rhamphorhynchus flew close to the water over which it hunted for fish.

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