page_title: Timeline of oviraptorosaur research
section_title: 1990s
hierarchical_section_title: Timeline of oviraptorosaur research / 20th century / 1990s
caption_attribution_description: Exhibit in the Houston Museum of Natural Science, Houston, Texas, USA. Photography was permitted in the museum without restriction.
context_page_description: This timeline of oviraptorosaur research is a chronological listing of events in the history of paleontology focused on the oviraptorosaurs, a group of beaked, bird-like theropod dinosaurs. The early history of oviraptorosaur paleontology is characterized by taxonomic confusion due to the unusual characteristics of these dinosaurs. When initially described in 1924 Oviraptor itself was thought to be a member of the Ornithomimidae, popularly known as the "ostrich" dinosaurs, because both taxa share toothless beaks. Early caenagnathid oviraptorosaur discoveries like Caenagnathus itself were also incorrectly classified at the time, having been misidentified as birds.
  The hypothesis that caenagnathids were birds was questioned as early as 1956 by Romer, but not corrected until Osmolska formally reclassified them as dinosaurs in 1976. Meanwhile, the classification of Oviraptor as an ornithomimid persisted unquestioned by researchers like Romer and Steel until the early 1970s when Dale Russell argued against the idea in 1972.
context_section_description: 1991
  Jerzykiewicz and Russell observed that oviraptorosaurs seem to have been most common during the Djadokhta stage.
  Sabath described an oviraptorosaur nest mound.
  1992
  Smith interpreted the biomechanics of oviraptorosaur jaws to imply that these dinosaurs were actually herbivorous.
  1993
  Jerzykiewicz and others observed that oviraptorosaurs seem to have been most common in central Asia.
  Currie, Godfrey, and Nessov described the new genus and species Caenagnathasia martinsoni.
  Currie and others built a case for interpreting oviraptorosaurs as egg-eaters who supplemented their diet with small prey. They noted supporting traits like the animals' ability to give a "powerful nipping bite" with the front of its beak. Oviraptorosaurs also had tooth-like projections from the roof of the mouth, which resemble similar adaptations in modern egg-eating mammals. The orientation of the throat on the underside of the jaw is also consistent with this reconstruction of oviraptorosaur paleoecology.
  Russell and Dong argued that the Maniraptora (which includes Oviraptorosauria) was a polyphyletic assemblage of unrelated groups. Instead they classified the traditional oviraptorosaurs with the ornithomimids, therizinosauroids, and troodontids in a new, greatly expanded Oviraptorosauria.
  1994
  Norell and others reported the discovery of a tiny theropod skeleton in an oviraptorid nest. They suggested this find was evidence that oviraptorosaur hunted tiny game. They also noted that the supposed Protoceratops eggs of the Central Asiatic Expeditions actually preserved the embryonic remains of oviraptorosaurs.
  1996
  Currie reported the presence of nests of large eggs more than 40 centimetres (16 in) long in China. Oviraptorosaurs would come to be considered possible candidates for the egg layers.
  Dong and Currie reported the discovery of an oviraptorid from the Djadokhta Formation of northern China preserved on top of a nest of eggs. This overturned more than 60 years of interpreting the Oviraptor of the Central Asiatic Expeditions as a rapacious egg-thief in favor of it likely being a faithful mother at her nest. The researchers reconstructed the way mother oviraptorosaurs built their nests. The standing mother would lay a pair of eggs and bury them by hand. Then she would turn and repeat the process until she had made a ring of egg-pairs completely around herself. Since by then the area where she was standing would be higher than the eggs, she would repeat the process with another ring of egg-pairs as a second layer. This process would gradually build an egg mound containing as many as 30 eggs in up to three layers.
  1997
  Sues published a critical review of earlier interpretations of the oviraptorosaurs' evolutionary relationships and formulated the clade's first synapomorphy-based diagnosis. He also performed a cladistic analysis and found oviraptorosaurs to be the sister group of the therizinosaurs.
  Sereno regarded oviraptorosaurs as maniraptorans and found them to be the sister group of Paraves (which includes deinonychosaurs and birds) in a cladistic analysis.
  Padian and others published a cladistic definition for Oviraptorsauris for the first time; all taxa closer to Oviraptor than to birds.
  Barsbold described the new genus Rinchenia for the species Oviraptor mongoliensis. Barsbold credited Currie and Padian for defining Oviraptorosauria as the Oviraptoridae and all taxa closer to Oviraptor.
  1998
  Sereno regarded oviraptorosaurs as maniraptorans and found them to be the sister group of Paraves (which includes deinonychosaurs and birds) in a cladistic analysis. He defined oviraptorosaurs as all maniraptorans closer to Oviraptor than to Neornithes.
  Currie, Norell, and Ji described the new genus and species Caudipteryx zoui.
  Ji and others reported the presence of gastroliths in Caudipteryx. These are evidence for an herbivorous diet.
  Makovicky and Sues considered oviraptorosaurs to be the sister group of the therizinosaurs.
  1999
  Sereno found Caudipteryx to be a basal oviraptorosaur. He also erected the clade Caenagnathoidea for the caenagnathids a
caption: Cast of a Caudipteryx zoui specimen, Houston Museum of Natural Science
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