Editing Troodon (section)

===Naming of related species===
[[File:Troodontid teeth.jpg|thumb|right|Comparison of [[troodontid]] teeth; A is the ''T. formosus'' holotype]] 
The first specimens assigned to ''Troodon'' that were not teeth were both found by Sternberg in the early 1930s in the [[Dinosaur Park Formation]] of [[Alberta]]. The first was named ''[[Stenonychosaurus inequalis]]'' by Sternberg in 1932 based on a foot, fragments of a hand, and some tail vertebrae. A remarkable feature of these remains was the enlarged claw on the second toe, which is now recognized as characteristic of early [[Paraves|paravians]]. Sternberg initially classified ''Stenonychosaurus'' as a member of the family [[Coeluridae]]. The second, a partial lower jaw bone, was described by Gilmore (1932) as a new species of lizard which he named ''[[Polyodontosaurus| Polyodontosaurus grandis]]''. In 1951, Sternberg later recognized ''P. grandis'' as a possible synonym of ''Troodon'' and speculated that, since ''Stenonychosaurus'' had a "very peculiar [[pes (zoology)|pes]]" and ''Troodon'' "equally unusual teeth", they may be closely related. Unfortunately, no comparable specimens were available at that time to test the idea. In a recent revision of the material by van der Reest & Currie, ''Polyodontosaurus'' was determined to be a ''nomen dubium'', not fit for synonymy with other taxa.<ref name=LS2017/>

A more complete skeleton of ''Stenonychosaurus'' was described by [[Dale Russell]] in 1969 from the Dinosaur Park Formation, which eventually formed the scientific foundation for a famous life-sized sculpture of ''Stenonychosaurus'' accompanied by its fictional, [[humanoid]] descendant, the [[Stenonychosaurus#The "Dinosauroid"|"dinosauroid"]].<ref name=russell1982>{{Cite journal | last1 = Russell | first1 = D. A. | last2 = Séguin | first2 = R. | year = 1982 | title = Reconstruction of the small Cretaceous theropod ''Stenonychosaurus inequalis'' and a hypothetical dinosauroid | url = https://archive.org/details/syllogeus37nati | journal = Syllogeus | volume = 37 | pages = [https://archive.org/details/syllogeus37nati/page/n8 1]–43 }}</ref> ''Stenonychosaurus'' became a well-known theropod in the 1980s, when the feet and braincase were described in more detail. Along with ''[[Saurornithoides]]'', it formed the family [[Saurornithoididae]]. Based on differences in tooth structure and the extremely fragmentary nature of the original ''Troodon formosus'' specimens, saurornithoidids were thought to be close relatives, while ''Troodon'' was considered a dubious possible relative of the family. [[Phil Currie]], reviewing the pertinent specimens in 1987, showed that supposed differences in tooth and jaw structure among troodontids and saurornithoidids were based on age and position of the tooth in the jaw, rather than a difference in species. He reclassified ''Stenonychosaurus inequalis'', ''Polyodontosaurus grandis'', and ''[[Pectinodon bakkeri]]'' as junior synonyms of ''Troodon formosus''. Currie also made Saurornithoididae a junior synonym of Troodontidae.<ref name=currie1987>{{Cite journal | last1 = Currie | first1 = P. | year = 1987 | title = Theropods of the Judith River Formation | journal = Occasional Paper of the Tyrrell Museum of Palaeontology | volume = 3 | pages = 52–60 }}</ref> In 1988, [[Gregory S. Paul]] went farther and included ''Saurornithoides mongoliensis'' in the genus ''Troodon'' as ''T. mongoliensis'',<ref name=paul1988b>{{cite book |last=Paul |first=G.S. |year=1988 |title=Predatory Dinosaurs of the World |location=New York |publisher=Simon and Schuster |pages=[https://archive.org/details/predatorydinosau00paul/page/398 398–399] |isbn=978-0-671-61946-6 |url-access=registration |url=https://archive.org/details/predatorydinosau00paul/page/398 }}</ref> but this reclassification, along with many other unilateral synonymizations of well known genera, was not adopted by other researchers. Currie's classification of all North American troodontid material in the single species ''Troodon formosus'' became widely adopted by other [[paleontology|paleontologists]] and all of the specimens once called ''Stenonychosaurus'' were referred to as ''Troodon'' in scientific literature through the early 21st century.