Pteranodon
"Pteranodon" was the first pterosaur found outside of Europe. Its fossils first were found by Othniel Charles Marsh in 1870, in the Late Cretaceous Smoky Hill Chalk deposits of western Kansas. These chalk beds were deposited at the bottom of what was once the Western Interior Seaway, a large shallow sea over what now is the midsection of the North American continent. These first specimens, YPM 1160 and YPM 1161, consisted of partial wing bones, as well as a tooth from the prehistoric fish "Xiphactinus", which Marsh mistakenly believed to belong to this new pterosaur (all known pterosaurs up to that point had teeth). In 1871, Marsh named the find ""Pterodactylus oweni"", assigning it to the well-known (but much smaller) European genus "Pterodactylus". Marsh also collected more wing bones of the large pterosaur in 1871. Realizing that the name he had chosen had already been used for Harry Seeley's European pterosaur species "Pterodactylus oweni" in 1864, Marsh re-named his giant North American pterosaur Pterodactylus occidentalis, meaning "Western wing finger," in his 1872 description of the new specimen. He also named two additional species, based on size differences: Pterodactylus ingens (the largest specimen so far), and Pterodactylus velox (the smallest).
Saurornithoides
Originally, only one or possibly two individuals of "Saurornithoides" were known, closely associated within the same layer of the Djadochta Formation of Mongolia. The fossils were found on 9 July 1923 by a Chinese employee of an American Museum of Natural History expedition, Chih. The material contained a single skull and jaw in association, and vertebrae, a partial pelvis, hindlimb and foot associated nearby. More bones were initially included but later shown to belong to "Protoceratops". Henry Fairfield Osborn at first intended to name the animal "Ornithoides", the "bird-like one", and in 1924 mentioned this name in a popular publication but without a description so that it remained an invalid "nomen nudum". He then formally described the remains in the same year, finding them to be a new genus and species, which he named "Saurornithoides mongoliensis". The generic name was chosen because of the bird-like bones of the taxon, which was thought to represent a megalosaurian, translating as "saurian with bird-like rostrum". "Saurornithoides" was noted to resemble "Velociraptor", although more sluggish according to Osborn. The holotype specimen is AMNH 6516. This specimen was the first troodontid skeleton found, though at the time the connection with "Troodon", then known only from its teeth, was not realised.
In 1964, another specimen was described from the Late Cretaceous of Mongolia. The first specimen ever collected by a professional Mongolian palaeontologist, it was given the specimen number IGM 100/1. In 1974, it was described by Rinchen Barsbold as a new species, "Saurornithoides junior". It was assigned to the genus based on cranial comparisons, as well as the similar provincialism. However, since the description, many more troodontids have been described with cranial material, and as such, a 2009 study on "Saurornithoides" reassigned this species to its own genus, "Zanabazar".