Pteranodon

***Pteranodon*** (meaning "toothless wing") is a genus of pterosaur that included some of the largest known flying reptiles, with wingspans over 7 meters (23 feet). They lived during the late Cretaceous geological period of North America in present-day Kansas, Alabama, Nebraska, Wyoming, and South Dakota. More fossil specimens of *Pteranodon* have been found than any other pterosaur, with about 1,200 specimens known to science, many of them well preserved with nearly complete skulls and articulated skeletons. It was an important part of the animal community in the Western Interior Seaway.

*Pteranodon* was a pterosaur, meaning that it is not a dinosaur. By definition, all dinosaurs belong to one of the two groups within Dinosauria, i.e. Saurischia or Ornithischia. As such, this excludes pterosaurs. Nonetheless, *Pteranodon* is frequently featured in dinosaur media and is strongly associated with dinosaurs by the general public. While not dinosaurs, pterosaurs such as *Pteranodon* form a clade closely related to dinosaurs as both fall within the clade Avemetatarsalia.

## Description

*Pteranodon* species are extremely well represented in the fossil record, allowing for detailed descriptions of their anatomy and analysis of their life history. Over 1,000 specimens have been identified, though less than half are complete enough to give researchers good anatomical information. Still, this is more fossils material than is known for any other pterosaur, and it includes both male and female specimens of various age groups and possibly species.

Adult *Pteranodon* specimens from the two major species can be divided into two distinct size classes. The smaller class of specimens have small, rounded head crests and very wide pelvic canals, even wider than those of the much larger size class. The size of the pelvic canal probably allowed the laying of eggs, indicating that these smaller adults are females. The larger size class, representing male individuals, have narrow hips and very large crests, which were probably for display.

Adult male *Pteranodon* were among the largest pterosaurs, and were the largest flying animals known until the late 20th century, when the giant azhdarchid pterosaurs were discovered. The wingspan of an average adult male *Pteranodon* was 5.6 meters (18 ft). Adult females were much smaller, averaging 3.8 meters (12 ft) in wingspan. The largest specimen of *Pteranodon longiceps* from the Niobrara Formation measured 6.25 meters (20.5 ft) from wingtip to wingtip. An even larger specimen is known from the Pierre Shale Formation, with a wingspan of 7.25 meters (23.8 ft), though this specimen may belong to the distinct genus and species *Geosternbergia maysei*. While most specimens are found crushed, enough fossils exist to put together a detailed description of the animal.

Methods used to estimate the mass of large male *Pteranodon* specimens (those with wingspans of about 7 meters) have been notoriously unreliable, producing a wide range of estimates. In a review of pterosaur size estimates published in 2010, researchers Mark Witton and Mike Habib argued that the largest estimate of 544 kg is much too high and an upper limit of 200 to 250 kg is more realistic. Witton and Habib considered the methods used by researchers who obtained smaller mass estimates equally flawed. Most have been produced by scaling modern animals such as bats and birds up to *Pteranodon* size, despite the fact that pterosaurs have vastly different body proportions and soft tissue anatomy from any living animal.

Other distinguishing characteristics that set *Pteranodon* apart from other pterosaurs include narrow neural spines on the vertebrae, plate-like bony ligaments strengthening the vertebrae above the hip, and a relatively short tail in which the last few vertebrae are fused into a long rod. The entire length of the tail was about 3.5% as long as the wingspan, or up to 25 centimeters (9.8 in) in the largest males.

### Skull and beak

Unlike earlier pterosaurs, such as *Rhamphorhynchus* and *Pterodactylus*, *Pteranodon* had toothless beaks, similar to those of birds. *Pteranodon* beaks were made of solid, bony margins that projected from the base of the jaws. The beaks were long, slender, and ended in thin, sharp points. The upper jaw, which was longer than the lower jaw, was curved upward; while this normally has been attributed only to the upward-curving beak, one specimen (UALVP 24238) has a curvature corresponding with the beak widening towards the tip. While the tip of the beak is not known in this specimen, the level of curvature suggests it would have been extremely long. The unique form of the beak in this specimen led Alexander Kellner to assign it to a distinct genus, *Dawndraco*, in 2010.

The most distinctive characteristic of *Pteranodon* is its cranial crest. These crests consisted of skull bones (frontals) projecting upward and backward from the skull. The size and shape of these crests varied due to a number of factors, including age, sex, and species. Male *Pteranodon sternbergi*, the older species of the two described to date (and sometimes placed in the distinct genus *Geosternbergia*), had a more vertical crest with a broad forward projection, while their descendants, *Pteranodon longiceps*, evolved a narrower, more backward-projecting crest. Females of both species were smaller and bore small, rounded crests. The crests were probably mainly display structures, though they may have had other functions as well.

## *Pteranodon* in The Amazing Dinosaur Adventure

### Characters

Alex the *Pteranodon*Alex's MotherAlex's SiblingsBrian the *Pteranodon*Aubrey the *Pteranodon*
### Anonymous

Green *Pteranodon*, from *The Great Day of the Pterosaurs* during the song *Flip, Flap, and Fly*