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.
Strathcona Fiord
The first High Arctic terrestrial fossil vertebrates were discovered in 1975, in the Strathcona Fiord by a team led by Mary Dawson from the Carnegie Museum. These earliest finds include the fossil remains of an alligator, considered to be "Allognathosuchus", and also small arboreal mammals called "plagiomenids". Since then, field expeditions in Strathcona Fiord have yielded a much more complete picture of the biodiversity of the Eocene Arctic. Although, Eocene fossil vertebrates are known from other areas on Ellesmere Island (e.g., Stenkul Fiord), and Axel Heiberg Island, Strathcona Fiord has yielded the richest vertebrate fossil record.