Pterodactyl, Pteranodon & Other Flying 'Dinosaurs'

Kim Ann Zimmermann, LiveScience Contributor

Date: 17 October 2012 Time: 05:45 PM ET

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Pterodactyl is the common term for the winged reptiles properly called pterosaurs. Scientists typically shy away from the term and concentrate on individual genera, Pterodactylus and Pteranodon in particular. There are more than 30 pterosaur genera.

Small species of pterosaurs developed during the Triassic Period, about 230 to 200 million years ago. More advanced forms reigned during the Jurassic and Cretaceous periods, 200 to 65 million years ago. Pterosaurs lived among the dinosaurs and became extinct about the same time, but they were not dinosaurs; they were flying reptiles. Modern birds did not descend from pterosaurs; their ancestors were small, feathered, terrestrial dinosaurs.

Artwork by Scott Hartman reveals the bone structure of Pteranodon.
CREDIT: © Scott Hartman / All rights reserved

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The first pterosaur to be discovered was Pterodactylus, identified in 1784 by Italian scientist Cosimo Collini, although he thought he had discovered a marine creature that used its wings as paddles. A French naturalist, Georges Cuvier, coined the term "Ptero-dactyle" in 1809 after the discovery of a fossil skeleton in Bavaria, Germany. This was the term used until scientists realized they were finding different genera of flying reptiles. However, "Pterodactyl" stuck as the popular term.

The name comes from the Greek pterodaktulos, meaning "winged finger," which is an apt description of its flying apparatus. Like all pterosaurs, the wings of Pterodactylus were formed by a skin and muscle membrane stretching from its elongated fourth finger to its hind limbs. Some scientists think pterosaurs were more suited to gliding than active flying.

Sizes of pterosaurs

Pterodactylus was a comparatively small pterosaur, with an estimated adult wingspan of about 5 feet (1.5 meters). There was some confusion early on as to the size of the Pterodactylus, as some of the specimens turned out to be juveniles rather than adults.

Pteranodon, discovered in 1876 by Othneil C. March, was much bigger. The adult male Pteranodon had an average wingspan of 18 feet (5.6 meters), and adult females were much smaller, with an average wingspan of 12 feet (3.8 meters).

The smallest pterosaur, called Nemicolopterus crypticus, was discovered in 2011 in the western part of China's Liaoning Province. It had a wingspan of only 10 inches (25 centimeters). One of the largest pterosaurs is believed to be Quetzalcoatlus northropi, whose wingspan reached 35 feet (10 m). Another large specimen was Coloborhynchus, with a wingspan of about 23 feet (7 meters). This discovery followed an examination of a fossil that had been in the Natural History Museum of London since 1884.

Physical characteristics

In addition to flying, fossil footprints suggest that pterosaurs could move on the ground using four feet, like bats. But it is not known how much of their time was spent on the ground or how quickly they could run.

Pterosaurs had long necks covered in long, bristle-like structures with throat pouches extending from about the middle of the lower jaw to the upper part of the neck. Their skulls were long and narrow and contained about 90 large, conical teeth. The teeth extended back from the tips of both jaws, and became smaller farther away from the jaw tips. The teeth were long and slender, giving rise to the theory that they were used as tools for straining.

A distinguishing feature of pterosaurs was the crest on their heads. The crest was composed mainly of soft tissues and was covered in scales. The long, hardened fibers were twisted together to form a spiral pattern inside the conical part of the crest. Since the crest was evident in adult species, it is thought to have been for display rather than practical purposes. Recent studies and more thorough examination of old specimens have shown that crests were more widespread than previously thought. While Pteranodon is the most familiar example, it is now believed that other pterosaurs had crests as well.

Other features, including proportions of its limbs, number of teeth and size and shape of its skull, varied more widely based on the level of maturity than seen in other prehistoric creatures.

What did pterosaurs eat?

Pterosaurs were carnivores, and survived mostly by scavenging. In the first few months of life, they ate insects. As adults they caught fish with their long beaks. They would also feed on carcasses of dinosaurs and other animals.

Because fish was a favorite food, pterosaurs lived primarily near the shoreline. At first, scientists speculated that pterosaurs were aquatic animals because of their close proximity to water and believed their wings were used to power them through the water, but that theory was later rejected after more remains were discovered. Some fossils have been discovered in caves. Scientists also believe they may have lived in large groups like many sea birds do today.

Pterosaurs in general were obviously more mobile than their land-based counterparts, so they were more scattered than most. It is believed they made their homes in parts of the Americas, Guam, China, Japan, England, Germany, France and Africa, among other places.

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