Oviraptoridae

Oviraptorids Temporal range: Late Cretaceous, 84–66 Ma PreЄ Є O S D C P T J K Pg N
Fossil skeleton of Khaan mckennai
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Reptilia
Clade:	Dinosauria
Order:	Saurischia
Suborder:	Theropoda
Superfamily:	†Caenagnathoidea
Family:	†Oviraptoridae Barsbold, 1976
Type species
†Oviraptor philoceratops Osborn, 1924
Subgroups
†Banji †Citipati †Luoyanggia †Huanansaurus †Nomingia †Oviraptor †Rinchenia †Shixinggia †Tongtianlong †Wulatelong †Yulong †"Ingeniinae" †Ajancingenia †Conchoraptor †Ganzhousaurus †Heyuannia †Jiangxisaurus †Khaan †Machairasaurus †Nemegtomaia

Oviraptoridae is a group of bird-like, herbivorous and omnivorous maniraptoran dinosaurs. Oviraptorids are characterized by their toothless, parrot-like beaks and, in some cases, elaborate crests. They were generally small, measuring between one and two metres long in most cases, though some possible oviraptorids were gigantic. Oviraptorids are currently known only from the Late Cretaceous of Asia, with the most well-known species and complete specimens found only in the Gobi Desert of Mongolia and northwestern China.

The most characteristic feature of this group is the skull structure. Oviraptorids had short snouts and very deep mandibles. Some taxa (Oviraptor, Citipati, Rinchenia) had a midline crest on top of the skull, resembling that of a cassowary. Other distinguishing characters include a bony spike intruding on the mandibular fenestra, nostrils placed very high and far back on the snout, an extremely thin bony bar beneath the eye, and highly pneumatized skull bones. Like their relatives the caenagnathids, the jaws were edentulous (with no teeth), having instead two small bony projections on the roof of the mouth.

The classification of the oviraptorids has been controversial. Most studies divide oviraptorosaurs into two primary sub-groups, the Caenagnathidae and the Oviraptoridae. However, some phylogenetic studies have suggested that many traditional members of the Caenagnathidae may more closely related to the crested oviraptorids. Because of this, and the fact that at least one study found that Caenagnathus itself may not have been part of the 'caenagnathid' group, Tom Holtz (2010) placed that group close to the Oviraptoridae and termed it the Elmisauridae, though this idea has not gained consensus among other researchers.

The Oviraptoridae itself is traditionally divided into two "subfamilies": the small, short-armed, and mainly crestless subfamily "Ingeniinae" (the name was preoccupied by an invertebrate group), defined as a clade (Ajancingenia + Conchoraptor), and the larger, crested, long-armed Oviraptorinae (Oviraptor + Citipati). Several recent phylogenetic studies have shown that Oviraptor is the most primitive known oviraptorid, thus making Citipati a closer relative of the "ingeniines" and this traditional division into crestless and crested forms artificial.

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Wikipedia