Oviraptor

Oviraptor philoceratops, whose name means "egg thief, lover of ceratopsians," was described by Henry Fairfield Osborn in 1924. The name was based on a partial skeleton found on a clutch of eggs in Mongolia, which Osborn assumed the animal was raiding. This interpretation was corrected 70 years later when Norell et al. (1995) identified the eggs as Oviraptor's own. They found an oviraptorid embryo inside an egg identical to those in the original "raiding" find, proving the dinosaur was actually a parent tending its nest.

This small, lightly built theropod had a deep, short skull with a beak-like structure. It lacked teeth in its upper jaw, possessing only two tooth-like projections on its palate. While the holotype's skull crest is poorly preserved, close relatives like Citipati osmolskae show prominent, tall casques. Oviraptor had a long neck, three-fingered grasping hands, and long, gracile legs. Based on its place in the dinosaur family tree and direct evidence from its relatives, it was almost certainly covered in feathers, including specialized wing and tail plumage.

The most significant discovery related to this genus is the evidence for brooding behaviour. Several oviraptorid fossils, most notably the Citipati specimens IGM 100/979 ("Big Mama") and IGM 100/1004, show adults sitting on egg clutches. Their arms are folded over the eggs in a posture identical to that of modern birds. This represents some of the most compelling evidence for bird-like nesting habits in non-avian dinosaurs.

The animal's diet is still a subject of research. Its toothless beak and palate prongs suggest it did not tear meat like typical theropods. Hypotheses include feeding on molluscs, seeds, fruit, or even other dinosaur eggs. However, the discovery of lizard and other small vertebrate remains in the stomach region of some specimens suggests a more omnivorous diet.

• AMNH 6517 — Osborn's holotype, American Museum of Natural History; partial skeleton with associated egg clutch.
• Big Mama (IGM 100/979, Citipati osmolskae) — close relative; Mongolian Academy of Sciences; adult brooding clutch.
• Additional embryo-bearing eggs from the Mongolian deposits.

Genus identity — Many "Oviraptor" specimens have been reassigned to other oviraptorids (Citipati, Khaan, Conchoraptor) on closer study; the holotype itself is somewhat fragmentary, and Oviraptor in the strict sense is now a fairly narrow taxon. Diet — molluscivory vs herbivory vs omnivory unresolved. Crest function — display, species recognition, or thermoregulation; consensus tilts toward display.

Oviraptor is the source of one of paleontology's best-known cautionary tales — the egg-thief that was actually a parent. It appears in Prehistoric Planet, Walking with Dinosaurs, and most modern dinosaur books. Its name has stuck despite being wrong, an example of nomenclatural conservatism.

• theropoda
• troodon
• velociraptor
• protoceratops

• Osborn, H. F. (1924). Three new Theropoda, Protoceratops zone, central Mongolia. American Museum Novitates, 144, 1–12.
• Norell, M. A., Clark, J. M., et al. (1995). A nesting dinosaur. Nature, 378, 774–776.
• Clark, J. M., Norell, M. A., & Chiappe, L. M. (1999). An oviraptorid skeleton from the Late Cretaceous of Ukhaa Tolgod. American Museum Novitates, 3265, 1–36.
• Funston, G. F., et al. (2020). Oviraptorosaurian biology, ecology, and evolution. Anatomical Record, 303, 925–956.