Why pterosaurs are not dinosaurs

Because they flew and their front limbs stretch out to the sides, they are not dinosaurs. Pterosaurs lived from the late Triassic Period to the end of the Cretaceous Period, when they went extinct along with dinosaurs.

Pterosaurs were carnivores, feeding mostly on fish and small animals. Many had hooked claws and sharp teeth that they used to grab their prey. Pterosaurs evolved into dozens of individual species. Some were as large as F fighter jets, while others were as small as paper airplanes. They were also the first animals after insects to evolve powered flight.

However, not all pterosaurs could fly. Pterodactylus flew using wings formed by a tough, thin membrane stretching along their bodies to their elongated fourth finger. Like birds, pterosaurs had lightweight, hollow bones. Pterosaur skeletons survive as fossils only when their bodies came to rest in a very protected environment.

Most pterosaur remains come from species that lived near the ocean or sea. Many Pterodactylus fossils are preserved in Bavaria, Germany. Rather than pushing off the ground with their legs, pterosaurs used their arms in a pole-vault type of motion to launch themselves skyward. Interesting stuff, but I quickly became irritated by some of the popular coverage of the new research.

Whenever a story about pterosaurs makes it into mainstream news outlets, it is almost inevitable the flying archosaurs are going to be mistakenly called "dinosaurs" by at least one source. In this case the British newspaper the Telegraph and the venerable BBC were two of the main offenders, each declaring that pterosaurs were dinosaurs in their headlines.

It might be easy to brush off my complaint as a case of paleo-pedantry, but word choice matters. Calling a pterosaur a dinosaur is an error of the same order of magnitude as saying that our species is a marsupial, but to understand why we need to flesh out the evolutionary relationships of these animals. Let's start from the bottom and work our way up. This was the term used until scientists realized they were finding different genera of flying reptiles. However, "pterodactyl" stuck as the popular term.

Pterodactylus comes from the Greek word pterodaktulos , meaning " winged finger ," which is an apt description of its flying apparatus. The primary component of the wings of Pterodactylus and other pterosaurs were made up of a skin and muscle membrane that stretched from the animals' highly elongated fourth fingers of the hands to the hind limbs. The reptiles also had membranes running between the shoulders and wrists possibly incorporating the first three fingers of the hands , and some groups of pterosaurs had a third membrane between their legs, which may have connected to or incorporated a tail.

Early research suggested pterosaurs were cold-blooded animals that were more suited to gliding than active flying. However, scientists later discovered that some pterosaurs, including Sordes pilosus and Jeholopterus ninchengensis , had furry coats consisting of hairlike filaments called pycnofibers, suggesting they were warm-blooded and generated their own body heat, according to a study in the Chinese Science Bulletin. What's more, a study in the journal PLOS ONE suggested pterosaurs had powerful flight muscles, which they could use to walk as quadrupeds on all fours like vampire bats and vault into the air.

Once airborne, the largest pterosaurs Quetzalcoatlus northropi could reach speeds of over 67 mph kph for a few minutes and then glide at cruising speeds of about 56 mph 90 kph , the study found. Pterodactylus antiquus the only known species of the genus was a comparatively small pterosaur, with an estimated adult wingspan of about 3.

There was some confusion early on as to the size of the Pterodactylus , because some of the specimens turned out to be juveniles rather than adults. Pteranodon , discovered in by Othniel C. Marsh, was much bigger. It had a wingspan that ranged from 9 to 20 feet 2.

The smallest pterosaur , called Nemicolopterus crypticus , was discovered in the western part of China's Liaoning Province. It had a wingspan of only 10 inches 25 centimeters , according to a description of the animal, published in the journal Proceedings of the National Academy of Sciences. One of the largest pterosaurs is believed to be Quetzalcoatlus northropi, whose wingspan reached 36 feet 11 m , according to the PLOS ONE article.

Another large pterosaur was Coloborhynchus capito , which had a wingspan of about 23 feet 7 m.