Oviraptorosauria Barsbold, 1976

Rauhut, Oliver W. M., 2003, The interrelationships and evolution of basal theropod dinosaurs, Special papers in palaeontology 69, pp. 1-213 : 40

Oviraptorosauria Barsbold, 1976 a

Included taxa. Caenagnathidae Sternberg, 1940 : Caenagnathasia martinsoni Currie, Godfrey and Nessov, 1993 ; Chirostenotes elegans (Parks, 1933) ; Chirostenotes pergracilis Gilmore, 1924 a ; Elmisaurus rarus Osmólska, 1981 . Oviraptoridae Barsbold, 1976 b : Citipati osmolskae Clark, Norell and Barsbold, 2001 ; Conchoraptor gracilis Barsbold, 1986 ; Ingenia yanshini Barsbold, 1981 ; Khaan mckennai Clark, Norell and Barsbold, 2001 ; Nomingia gobiensis Barsbold, Osmólska, Watabe, Currie and Tsogtbataar, 2000 ; Oviraptor mongoliensis Barsbold, 1986 ; Oviraptor philoceratops Osborn, 1924 .

Temporal range. Turonian-Maastrichtian.

Occurrence. Bissekty Formation, Uzbekistan; Judith River Formation, Alberta, Canada, and Montana, USA; Horseshoe Canyon Formation, Alberta, Canada; Nemegt Formation, Omnogov, Mongolia; Red beds of Khermeen Tsav, Omnogov, Mongolia; Beds of Bugeen Tsav, Bayankhongor, Mongolia; Djadokhta Formation, Omnogov, Mongolia; Bayan Mandahu Red beds, Nei Mongol Zizhiqu, China.

Diagnosis. Maxilla with broad palatal shelf bearing two longitudinal ridges and with posteromedial toothlike process; dentary with medial ridge; dorsal margin of dentary deeply concave; dentary with two long posterior processes separated by the external mandibular fenestra; coronoid process of dentary inflected dorsomedially; articular surface of lower jaw convex in lateral view, distinctly expanded laterally and medially, and raised above the dorsal margin of the mandibular ramus; proximal caudal vertebrae strongly pneumatised. The following characters might be synapomorphies of the Oviraptorosauria , but are currently unknown in caenagnathids: postorbital part of the skull subequal in length to the preorbital part (i.e. snout very short and high); suborbital fenestra closed, ectopterygoid contacts the palatine in a broad suture anteriorly (the condition in therizinosaurs might be similar, but is uncertain); premaxillary body as high as, or higher than the height of orbit.

Remarks. The first representatives of this peculiar group of dinosaurs ( Text-fig. 6f ) were described by Osborn (1924) and Gilmore (1924 a), although it was not then recognized that Chirostenotes Gilmore is a close relative of Oviraptor Osborn. In 1940 , Sternberg described two edentulous lower jaws from the Campanian Judith River Formation of Canada as a new genus of Cretaceous birds, Caenagnathus , and referred it to its own family, Caenagnathidae . All of these taxa received surprisingly little attention until new and better preserved material of oviraptorosaurs discovered in the Upper Cretaceous of Mongolia in the 1970s revealed the bizarre skull anatomy of these animals. Osmólska (1976) recognized the close similarities of the lower jaws of Caenagnathus and Oviraptor and Barsbold (1976 a, b) created the family Oviraptoridae and the suborder Oviraptorosauria. In 1981, Osmólska described some new theropod remains from the Late Cretaceous of Mongolia as Elmisaurus rarus and created the family Elmisauridae to include Elmisaurus , Chirostenotes and Macrophalangia Sternberg, 1932 . Currie and Russell (1988) confirmed the close relationships of Elmisaurus and Chirostenotes , and synonymized Macrophalangia with the latter genus. In the 1990 compendium ‘The Dinosauria ’ (Weishampel et al.), Currie listed Elmisaurus and Chirostenotes as elmisaurids, and referred the species O rnithomimus elegans Parks, 1933 to the latter genus. In the same compendium, Barsbold et al. listed the Oviraptoridae and the Caenagnathidae as members of the Oviraptorosauria .

In 1997, Sues described a new specimen of Chirostenotes from the Horseshoe Canyon Formation of western Canada. He presented a good case for arguing that Caenagnathus represents the same genus as Chirostenotes and consequently used the older family name Caenagnathidae Sternberg, 1940 , instead of Elmisauridae Osmolska, 1981 . He further concluded that caenagnathids and oviraptorids can be united as Oviraptorosauria , based on several cranial and postcranial synapomorphies. This view is followed here.

Figures

text-fig. 6. Skull reconstructions of representatives of Cretaceous OTUs in left lateral view, a, abelisaurid Camotaurus sastrei, Late Cretaceous (Campanian), Gorro Frigio Formation, Argentina; based on Bonaparte et al. (1990) and MACN CH 894. b, composite skull of a generalized baryonychid; mainly based on Suchomimus tenerensis (MNN GDF 501, 503-506) and Irritator challenged (SMNS 58022), with some elements reconstructed after Baryonyx walkeri (BMNH R 9951). c, carcharodontosaurid Carcharodontosaurus sahariens, Late Cretaceous (Cenomanian), Kem Kem beds, Morocco; based on Sereno et al. (1996) and SGM-Din 1, unpreserved elements shaded. D, dromaeosaurid Velociraptor mongoliensis, Late Cretaceous (Campanian), Djadokhta Formation, Mongolia; based on Barsbold (1983), Barsbold and Osmólska (1999), and AMNH 6515. e, ornithomimosaur Dromiceiomimus brevitertius, Late Cretaceous (Maastrichtian), Horseshoe Canyon Formation, Alberta, Canada; redrawn from Russell (1972). F, oviraptorosaur Oviraptor philoceratops, Late Cretaceous (Campanian), Djadokhta Formation, Mongolia; redrawn from Barsbold et al. (1990). G, therizinosauroid Erlikosaurus andrewsi, Late Cretaceous (Cenomanian- Turonian), Baynshiren Svita, Mongolia; based on Clark et al. (1994). H, tyrannosaurid Gorgosaurus libratus, Late Cretaceous (Campanian), Judith River Formation, Alberta, Canada, redrawn from Molnar et al. (1990). Abbreviations as in Text-figures 4 and 5, and: acc. op., accessory opening of unknown function in the premaxilla of Oviraptor (Barsbold et al. 1990); amf, anterior maxillary foramen; pn, pneumatic openings. Scale bars represent 50 mm (d-g) and 100 mm (a-c, h).