page_title: Timeline of pachycephalosaur research
section_title: 1950s
hierarchical_section_title: Timeline of pachycephalosaur research / 20th century / 1950s
caption_attribution_description: Hypothetical head-to-body interactions among pachycephalosaurids. Giraffa-style necking and parietal clashing in high-domed and large-horned specimens such as subadult Pachycephalosaurus (“Stygimoloch” and “Dracorex”).
context_page_description: This timeline of pachycephalosaur research is a chronological listing of events in the history of paleontology focused on the pachycephalosaurs, a group of dome-skulled herbivorous marginocephalian dinosaurs. One of the first major events related to the history of pachycephalosaur research actually regards the discovery of an unrelated dinosaur called Troodon, reported from the western United States by Joseph Leidy in 1856. The type specimen of Troodon was simply an unusual tooth, but the close resemblance between Troodon teeth and pachycephalosaur teeth would cause taxonomic confusion for over a century. This was resolved by Phil Currie in 1987, who realized that Troodon belonged to a group of bird-like carnivores then known as saurornithoidids, but since renamed Troodontidae after Troodon itself. The first scientifically documented true pachycephalosaur remains were discovered in Early Cretaceous rocks from England and named Stenopelix not long after Troodon was named in America. Other notable early finds include the well-known pachycephalosaur Stegoceras validum.
context_section_description: 1953 
  Birger Bohlin described the new species Troodon bexelli.
  1955
  Edwin Colbert first suggested that the domed heads of pachycephalosaurs were used as "battering ram[s]".
  1956
  Science fiction author Sprague de Camp was the first to specifically suggest that pachycephalosaurs used their domed heads to butt heads with other pachycephalosaurs.
caption: Artist's restoration of head-butting Pachycephalosaurus
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