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Oviraptor is a genus of small Mongolian theropod dinosaurs, first discovered by the paleontologist Roy Chapman Andrews, and first described by Henry Fairfield Osborn, in 1924. Its name is Latin for 'egg thief', referring to the fact that the first fossil specimen was discovered atop a pile of what were thought to be Protoceratops eggs, and the specific name philoceratops means "lover of ceratopsians", also given as a result of this find. In his 1924 paper, Osborn explained that the name was given due to the close proximity of the skull of Oviraptor to the nest (it was separated from the eggs by only four inches of sand). However, Osborn also suggested that the name Oviraptor "may entirely mislead us as to its feeding habits and belie its character".[1] In the 1990s, the discovery of nesting oviraptorids like Citipati proved that Osborn was correct in his caution regarding the name. These finds showed that the eggs in question probably belonged to Oviraptor itself, and that the specimen was actually brooding its eggs.

Oviraptor lived in the late Cretaceous period, during the late Campanian stage about 75 million years ago; only one definitive specimen is known (with associated eggs), from the Djadokhta Formation of Mongolia, though a possible second specimen (also with eggs) comes from the northeast region of Inner Mongolia, China, in an area called Bayan Mandahu.[2]

History of discovery[]

Flaming Cliffs site - Mongolia

The Flaming Cliffs of Mongolia in the Gobi Desert. The holotype remains of Oviraptor were found in this highly fossiliferous locality of the Djadokhta Formation

The first specimen of Oviraptor was discovered by the American Museum of Natural History expedition to Asia in 1923. It was found in the Gobi Desert of Mongolia. This is the same place Protoceratops was found. The specimen was an almost complete skull along with parts of the hands and neck vertebrae. It was found lying next to a nest of eggs that may have belonged to Protoceratops. Henry Fairfield Osborn thought the animal may have died while eating the eggs in the nest; perhaps it had been killed by an angry Protoceratops parent. This possible diet of eggs led Osborn to name the genus and species Oviraptor philoceratops, which means "egg plunderer, lover of ceratopsians".

At first Oviraptor was thought to be a member of the ornithomimidae but its fingers were not the same length and they ended in strongly curved claws. The ornithomimids had fingers about the same length and almost straight claws.

Description[]

Oviraptor digital1

Artist's restoration

Oviraptor size

Size compared to a human

Oviraptor philoceratops is known from a single partial skeleton (specimen number AMNH 6517), as well as a nest of about fifteen eggs that have been referred to this species (AMNH 6508).

When living, Oviraptor was one of the most bird-like of the non-avian dinosaurs. Its rib cage, in particular, displayed several features that are typical of birds, including a set of processes on each rib that would have kept the rib cage rigid. A relative of Oviraptor called Nominga was found with a pygostyle, which is a set of fused vertebrae that would later help support the tail feathers of birds. Skin impressions from more primitive oviraptorosaurs, like Caudipteryx and Protarchaeopteryx, clearly show an extensive covering of feathers on the body, feathered wings and feathered tail fans. A tail fan is also indicated by the presence of a pygostyle in Nomingia, suggesting that this feature was widespread among oviraptorosaurs. Additionally, the nesting position of the brooding Citipati specimens implies the use of feathered wings to cover the eggs.[3] Given the close anatomical similarity between these species and Oviraptor, it is highly likely that Oviraptor had feathers as well. On the other hand, there is one problem with the use of feathers to "brood" eggs. Since feather is good insulation, heat cannot easily transfer between the body of an animal and the eggs, if there is feather in between them. That is why many birds have a featherless patch of bare skin, known as the brood patch, to allow heat to flow freely from the bird's body to the eggs. So, if Oviraptor and Citipati were to cover their eggs with feathers, the feathers can only function to shield the eggs from the elements, such as the sun, wind or rain, but the feathers will not warm the eggs, regardless of whether Oviraptor and Citipati are endothermic or ectothermic.

Oviraptor is traditionally depicted with a distinctive crest, similar to that of the cassowary. However, re-examination of several oviraptorids show that this well-known, tall-crested species may actually belong to the genus Citipati, a relative of Oviraptor.[4] It is likely that Oviraptor did have a crest, but its exact size and shape are unknown due to crushing in the skull of the only recognized specimen.

Skull[]

Oviraptor skull

Drawing of the skull, type specimen AMNH 6517

The skull of Oviraptor was short with large eye sockets, a crest above the snout, and a deep lower jaw with a large fenestra (opening) in the middle. Like the ornithomimids, both the upper and lower jaws were beaklike and toothless. The crest was full of sinuses, or cavities, which were filled with air when it was alive. The unusual jaws show that the animal had a specialized diet. Unlike most theropods, except the ornithomimids, Oviraptor and other members of the family Caenagnathidae were probably herbivorous (plant-eaters).

Recently discovered specimens show that, aside from the skull, Oviraptor was quite similar to other theropods in terms of anatomy. An adult was about three feet tall at the shoulder and about six feet long, and the animal could use them to grasp. The long back legs show it had been a good runner. With no teeth, running may have been its only defense against other theropods.

Postcranial skeleton[]

Oviraptor Skeletal

Skeletal reconstruction of the holotype, known remains in white

Most Oviraptors had the size and appearance of large modern birds with the largest being smaller than an ostrich. Since the original specimen was discovered, several other skulls with skeletons have been found. These new specimens show that the size of the crest on each animal was different. The crest ranges from almost none to large.

These differences are probably because of the different ages of the animals. This is supported by the fact that the small crested skulls had large eye sockets while the large-crested forms had relatively small eye sockets. In many modern animals the size of the eye socket in proportion to the rest of the head gets smaller as the animal gets older, so the same may have been through for dinosaurs.

Oviraptor Restoration

Life restoration

Another studies say that the Oviraptor, like other small dinosaurs like Velociraptor, maybe had feathers on its body, helping the theory of the evolution of dinosaurs to birds become more realistic.

Oviraptor was closely related to the Caenagnathus, from Alberta. Other relatives of Oviraptor were Chirostenotes and Elmisaurus.

Classification[]

Oviraptor arms

Drawing of the left arm and both hands of type specimen AMNH 6517

Oviraptor was originally allied with the ornithomimids by Osborn due to its toothless beak. Osborn also found similarities with Chirostenotes, which is still considered a close relative of Oviraptor.[1] In 1976, Barsbold erected a new family to contain Oviraptor and its close kin, making Oviraptor the type genus of the Oviraptoridae.[5]

While the original specimen of Oviraptor was poorly preserved, especially the crushed and deformed skull, new and more complete oviraptorid specimens were assigned to the genus in the 1970s and 1980s. In 1976, Barsbold referred six additional specimens to the genus Oviraptor (including IGM 100/20 and 100/21),[5] but these were later reclassified in the new genus Conchoraptor.[6] Another specimen, IGN 100/42, is perhaps the most famous, owing to its well-preserved complete skull and large size. This specimen was referred to the genus Oviraptor by Barsbold in 1981[7] and came to represent Oviraptor in most popular depictions and in scientific studies of oviraptorids.[8] However, this specimen, with its distinctive tall, cassowary-like crest, was re-examined by the scientists who described the nesting oviraptorids, and found to resemble them more closely than the original specimens of Oviraptor. For this reason, they removed IGN 100/42 from the genus Oviraptor, provisionally re-classifying it as a species of Citipati.[4]

The cladogram below follows an analysis by Fanti et al., 2012.

Oviraptoridae

Oviraptor


unnamed

Rinchenia



Citipati



unnamed

Khaan


unnamed

Conchoraptor


unnamed

Machairasaurus


unnamed

"Ingenia" (=Ajancingenia)


unnamed

Nemegtomaia



Heyuannia








Paleobiology[]

Oviraptor philoceratops nest AMNH FR 6508

Fossilized nest, specimen AMNH FR 6508

As its name suggests, Oviraptor was originally presumed to have eaten eggs, based on its association with a fossilized nest (specimen number AMNH FR 6508) thought to belong to Protoceratops.[1] The idea of a crushing jaw was first proposed by H. F. Osborn, who believed that the toothless beak of the original skull, together with an extension of several bones below the jaw from the palate, would have made an "egg-piercing" tool. In 1977, Barsbold argued that the strength of its beak would indicate that it was strong enough to break the shells of mollusks such as clams, which are found in the same geological formation as Oviraptor. These bones form part of the main upper jaw bone or maxilla, which converge in the middle to form a pair of prongs. The rest of the bony palate, unlike all other dinosaurs, is extended below the jaw line and would have pushed into the space between the toothless lower jaws. A beak (rhamphotheca) covered the edges of upper and lower jaws and probably the palate, as proposed by Barsbold and Osborn.

Nesting Protoceratops

1922 Charles R. Knight painting showing Protoceratops guarding eggs now known to have belonged to Oviraptor

The discovery of nesting specimens of the related Citiparti, with the same types of egg in the original Oviraptor specimen, showed that the eggs actually belonged to Oviraptor, not Protoceratops, and that the type specimen was likely brooding the eggs, not feeding on them. While this discovery did not rule out the possibility that Oviraptor included eggs in its diet, its exact feeding strategies remain unknown. The only Oviraptor philoceratops skeleton preserved the remains of a lizard in the region of its stomach cavity,[9] implying that the species was at least partially carnivorous.[10]

Paleoecology[]

Oviraptor in Djadokhta Formation

Restoration of a resting Oviraptor at the Djadokhta Formation

The paleoenvironment of which individuals lived was semiarid, with alluvial settings and sand dunes similar to the Gobi Desert. The steppe landscape was sometimes ravaged by dust and sand storms, drained by intermittent streams and seasonal moisture. Although the Djadokhta Formation is known for its dusty semiarid environment, evidence presented by fluvial sedimentation, bodies of water sometimes appeared, though short-lived. Additionally, in the Campanian and the Maastrichtian, the climate often fluctuated to a more humid fluvial climate, as seen in the Nemegt Formation. Oviraptor lived alongside Bainoceratops, Protoceratops, Velociraptor, Saurornithoides, Pinacosaurus, Halszkaraptor, Tsaagan, Apsaravis, Byronosaurus, Citipati, Gobipteryx, Khaan, Khol, Shuuvuia and Minotaurosaurus.

Taphonomy[]

The holotype was found crouching over a nest, presumably hastily buried during a sandstorm, encased in sand before scavengers could arrive at the corpse and disarticulate the body. The individuals skull may have been flattened and distorted during fossilization. Kenneth Carpenter agrees that a sand storm is the most likely case as to why the eggs became fossilized.

JPInstitute.com Description[]

Oviraptor is a very unique dinosaur with some rather strange features. Instead of teeth, it has a beak and something not seen in any other dinosaur, two teeth in the roof of its mouth. The reason it got its name is that when it was first discovered, Oviraptor was sitting on a nest of eggs. It was thought it was stealing the eggs of another dinosaur. Years later, it was found that the eggs were its own and that it was trying to protect them from an approaching sandstorm.

Oviraptor has another unusual feature - it has a thin crest of bone on its forehead. This crest seems to have grown and changed throughout its entire life. It may have been used as a form of individual identification or to differentiate gender. Also, different species of the Oviraptor genus had different crests. It is not clear what Oviraptor ate. Since it was probably not eggs, and it had very strong jaws, some think it would have eaten shellfish that it could easily crack open. Others argue that it must have been an herbivore as its skull did not show characteristics for meat-eating.

Of particular note is that an as yet undescribed North American Oviraptor was discovered in 1996 in South Dakota. This specimen is very large, almost 20 feet long. A trackway has also been associated with this find.

Dinosaur Field Guide Description[]

Oviraptor (egg hunter") is dinosaur once thought to have been an egg hunter. It is now known to have been an egg protector! When paleontologists first found this little meat-eater in the Mongolian desert, it was sitting on top of a bunch of fossilized eggs. The scientists thought these eggs were from the horned dinosaur Protoceratops. Knowing that Oviraptor was a theropod, or meat-eating dinosaur, the scientists guessed that Oviraptor was about to eat the eggs. Many decades later, however, paleontologists discovered that these eggs were actually Oviraptor eggs, and that (like birds) Oviraptors sat on their eggs before they hatched. Since then, many Oviraptor nests (and nests of related dinosaurs) have been found with parents on top. Oviraptor is one of the oviraptorosaur dinosaurs. Like other Late Cretaceous oviraptorosaurs, Oviraptor had a deep, toothless beak. It also had long, grasping hands, which would have been useful for clutching food. The exact diet of Oviraptor is debated by paleontologists. The first skeleton of Oviraptor contained a lizard skeleton in its belly, so it definitely ate some meat. Some paleontologists, however, think that it may have eaten plants.

Fun Facts[]

Oviraptor's skull was so unusual that, when it was first being dug out of the rock, paleontologists were not sure which and was the front!

Trivia[]

Oviraptor was originally going to be named Fenestrosaurus("window lizard") because of the openings in its skull, but the paleontologist who named it thought that "egg hunter" was a more interesting.

Gallery[]

Appearance in other media[]

Jurassic Park[]

  • Though not in the theatrical cut, Oviraptor made an appearance in a deleted scene of Jurassic World: Dominion where it was shown in a pit fighting with a small Lystrosaurus. After some intimidation and bluffs from the theropod, the Lystrosaurus bit off its head with the rest of the body running in circles not unlike a chicken. This version of Oviraptor was depicted relatively accurately with proper plumage and proportions.


The Land Before Time[]


Links[]

https://web.archive.org/web/20040806054124fw_/http://www.jpinstitute.com/dinopedia/dinocards/dc_ovira.html

References[]

  1. 1.0 1.1 1.2 Osborn, H.F. (1924). "Three new Theropoda, Protoceratops zone, central Mongolia." American Museum Novitates, 144: 12 pp., 8 figs.; (American Museum of Natural History) New York. (11.7.1924).
  2. Dong and Currie, P. (1996). "On the discovery of an oviraptorid skeleton on a nest of eggs at Bayan Mandahu, Inner Mongolia, People's Republic of China." Canadian Journal of Earth Sciences, 33: 631-636.
  3. Paul, G.S. (2002). Dinosaurs of the Air: The Evolution and Loss of Flight in Dinosaurs and Birds. Baltimore: Johns Hopkins University Press.
  4. 4.0 4.1 Clark, J.M., Norell, M.A., & Barsbold, R. (2001). "Two new oviraptorids (Theropoda:Oviraptorosauria), upper Cretaceous Djadokhta Formation, Ukhaa Tolgod, Mongolia." Journal of Vertebrate Paleontology 21(2):209-213., June 2001.
  5. 5.0 5.1 Template:Cite journal
  6. Barsbold, R. (1986). "Raubdinosaurier Oviraptoren" [in Russian]. In: O.I. Vorob’eva (ed.), Gerpetologičeskie issledovaniâ v Mongol’skoj Narod−noj Respublike, 210–223. Institut èvolûcionnoj morfologii i èkologii životnyh im. A.N. Severcova, Akademiâ nauk SSSR, Moscow.
  7. Barsbold, R. (1981). "Toothless dinosaurs of Mongolia." Joint Soviet-Mongolian Paleontological Expedition Transactions, 15: 28-39. [in Russian]
  8. Barsbold, R., Maryanska, T., and Osmolska, H. (1990). "Oviraptorosauria," in Weishampel, D.B., Dodson, P., and Osmolska, H. (eds.). The Dinosauria. Berkeley: University of California Press, pp. 249-258.
  9. (1995) "Discovering Dinosaurs" U. of California Press
  10. Norell, Clark, Chiappe, and Dashzeveg, (1995). "A nesting dinosaur." Nature, 378: 774-776.
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