page_title: Pteranodon
section_title: A toothless pterosaur
hierarchical_section_title: Pteranodon / Discovery and history / A toothless pterosaur
caption_attribution_description: The skull of the type specimen of Pteranodon longiceps (YPM 1177) in left lateral view, collected by S.W. Williston on May 2, 1876 from the "Yellow Chalk" near the Smoky Hill River in western Kansas, and described by Marsh (1876). Photo adapted from Plate 1 of Eaton (1910). Note that the crest is broken off. The greatest preserved length of the skull is 73 cm (28 inches).
context_page_description: Pteranodon is a genus of pterosaur that included some of the largest known flying reptiles, with wingspans over 7 meters. 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 are 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.
context_section_description: While the first Pteranodon wing bones were collected by Marsh and Cope in the early 1870s, the first Pteranodon skull was found on May 2, 1876, along the Smoky Hill River in Wallace County (now Logan County), Kansas, USA, by Samuel Wendell Williston, a fossil collector working for Marsh. A second, smaller skull soon was discovered as well. These skulls showed that the North American pterosaurs were different from any European species, in that they lacked teeth and had bony crests on their skulls. Marsh recognized this major difference, describing the specimens as "distinguished from all previously known genera of the order Pterosauria by the entire absence of teeth." Marsh recognized that this characteristic warranted a new genus, and he coined the name Pteranodon ("wing without tooth") in 1876. Marsh reclassified all the previously named North American species from Pterodactylus to Pteranodon. He considered the smaller skull to belong to Pteranodon occidentalis, based on its size. Marsh classified the larger skull, YPM 1117, in the new species Pteranodon longiceps, which he thought to be a medium-sized species in between the small P. occidentalis and the large P. ingens. Marsh also named several additional species: Pteranodon comptus and Pteranodon nanus were named for fragmentary skeletons of small individuals, while Pteranodon gracilis was based on a wing bone that he mistook for a pelvic bone. He soon realized his mistake, and re-classified that specimen again into a separate genus, which he named Nyctosaurus. P. nanus was also later recognized as a Nyctosaurus specimen.
  In 1892, Samuel Williston examined the question of Pteranodon classification. He noticed that, in 1871, Seeley had mentioned the existence of a partial set of toothless pterosaur jaws from the Cambridge Greensand of England, which he named "Ornithostoma". Because the primary characteristic Marsh had used to separate Pteranodon from other pterosaurs was its lack of teeth, Williston concluded that "Ornithostoma" must be considered the senior synonym of Pteranodon. However, in 1901, Pleininger pointed out that "Ornithostoma" had never been scientifically described or even assigned a species name until Williston's work, and therefore had been a nomen nudum and could not beat out Pteranodon for naming priority. Williston accepted this conclusion and went back to calling the genus Pteranodon. However, both Williston and Pleininger were incorrect, because unnoticed by both of them was the fact that, in 1891, Seeley himself had finally described and properly named Ornithostoma, assigning it to the species O. sedgwicki. In the 2010s, more research on the identity of Ornithostoma showed that it was probably not Pteranodon or even a close relative, but may in fact have been an azhdarchoid, a different type of toothless pterosaur.
caption: Short-crested P. longiceps holotype specimen YPM1177, now interpreted as a female individual
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