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.
Uranocentrodon
Fossils of the animal now known as "Uranocentrodon" were first discovered in a sandstone quarry near Senekal in Free State, South Africa. The first example of these fossils was a fragmentary skull excavated by a local family. Subsequent excavations and searches undertaken by various parties unearthed more specimens which hailed from the quarry. Among these specimens included three nearly complete skeletons overlapping each other. The initial skull was determined to belong to the same individual as one of the skeletons. The skull and three skeletons were acquired by the Transvaal Museum and given the designations TM 75, TM 75d, and TM75h by E.C.N. van Hoepen. In 1911, he gave the formal name "Myriodon senekalensis" to the specimens by means of a brief description published in Dutch. He published a more comprehensive description a few years later in 1915. Two additional skulls were mentioned in this description, although their whereabouts are currently unknown. In 1917 it was determined that the name "Myriodon" was already in use by a genus of fish, and that a new name had to be used. Thus, van Hoepen renamed "Myriodon senekalensis" to "Uranocentrodon senekalensis", which roughly translates to "prickle-toothed palate of Senekal". The original Transvaal Museum specimens have collectively been termed the syntypes of "Uranocentrodon".