Pteranodon
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.
Paleontology in Kansas
In 1870, O. C. Marsh led a paleontological expedition into the western United States on behalf of Yale University. Late in the November of that year they visited the area around Fort Wallace. They spent several days prospecting for fossils in modern Wallace and Logan Counties along the banks of the Smoky Hill River. Persevering against cold weather, they made several finds. One was the nearly complete skeleton of the mosasaur "Clidastes" that took four days to excavate. Among the fossils discovered by Marsh's crew in western Kansas were the far ends of two pterosaur wing metacarpals. These were the first scientifically documented fossils of the pterosaur that would later be named "Pteranodon". This formal naming occurred six years later, in 1876.