Oviraptor philoceratops

Oviraptor philoceratops is the only known species of the extinct genus Oviraptor (lat. "thief of eggs") of the oviraptorid theropod dinosaur, which lived at the end of the Cretaceous period, approximately 75 million years ago, in the Campanian, in what is now Asia. Contrary to what the name suggests, there is no evidence that Oviraptor fed on eggs. Its fossils were found near a nest it was assumed to be attacking, but later studies revealed that the nest did in fact belong to Oviraptor. The popular depiction of Oviraptor, with a high crest, actually belongs to Citipati, a close relative.

Description

Comparison of sizes between a Oviraptor and a human.

Oviraptor philoceratops is known from a single partial skeleton, specimen number AMNH 6517, as well as a nearby nest of fifteen eggs that have been reported from this species, AMNH 6508. Oviraptor was a non-avian, bird-like dinosaur, measuring about 1.7 meters long, 0.70 meters tall, and weighing 25 kilograms. Its rib cage, in particular, exhibited several characteristics that are typical of birds, including a system of processes on each rib that would have kept the ribcage rigid. A relative of Oviraptor called Nomingia was found with a pygostyle, which is a set of fused vertebrae that would later help support the tail feathers of birds. Skin impressions of more primitive oviraptorosaurs, such as Caudipteryx and Protarchaeopteryx, clearly show extensive feather covering on the body, feathered wings, and feathered tail sails. A tail sail is also indicative of the presence of a pygostyle in Nomingia, suggesting that this feature was common among oviraptorosaurs. In addition, the position in the brooding nest of the Citipati specimens implies the use of wings in charge of covering the eggs. Given the high degree of anatomical similarity between these species and Oviraptor, it is highly probable that the latter also had feathers.

Traditionally Oviraptor has been described as having a large crest similar to that of the cassowary, but later studies indicated that the skull of said specimen corresponded to a Citipati, a relative close to Oviraptor. Given the phylogenetic relationships, it is likely that Oviraptor exhibited a crest, although in the absence of a skull, its presence and dimensions are impossible to ascertain. determine.

Ovirraptor skeleton model.

Contrary to what the name suggests, Oviraptor did not feed on eggs, which was presumed since its fossils were found near a nest assumed to belong to the genus Protoceratops, since this was the most abundant dinosaur in the formation. Studies later revealed that the nest did, in fact, belong to Oviraptor. As early as 1977, Barsbold argued that the strength of Oviraptor's jaws would have allowed it to open the shells of mollusks such as today's oysters, which were found in the same place as Oviraptor. The idea of crushing jaws was proposed by H. F. Osborn, who believed that the original specimen's lack of teeth, with the extension of the bones that form the roof of the mouth, constituted an egg-cracking tool, but this interpretation is being disputed. These bones They form part of the maxilla and mandible that converge to some extensions. The remainder of the bony palate, unlike in other dinosaurs, extends beyond the jaw line and may have occupied a toothless lower space in the jaw. A beak or rhamphotheca covered the edges of both jaws and probably the roof of the mouth as proposed by Barsbold and Osborn.

Discovery and research

Replica of the fossil of a skull Oviraptor in the Children's Museum of Indianapolis.

The remains of the first Oviraptor were found in Omnogov, Mongolia in the Djadochta Formation, during an expedition by the American Museum of Natural History, in 1924. The remains of a second possible specimen come from Mongolia Interior, China from an area called Bayan Mandahu. The first remains were found next to what was thought at the time to be a pile of Protoceratops eggs, so it was assumed that it fed on the eggs, looting the nests, for this reason its name is Latin for Oviraptor, "egg thief", and the name of the species philoceratops which means "ceratopos lover". In the article of his presentation, he explains his name because the remains were only 10 centimeters of sand from the eggs. However Osborn suggests that the name is not correct as it is more likely to have fed on bivalves. in a position to hatch its elongated eggs, very similar to those found next to the original Oviraptor, for which reason it is now believed that it was not stealing them, but on the contrary, it was protecting its offspring.

Skeleton Oviraptor.

Because the original remains of Oviraptor are poorly preserved, especially the crushed and deformed skull, new and more complete specimens have been assigned to this genus during the 1970s and 1980s. In 1976, Barsbold referred six additional specimens to the genus Oviraptor, including IGM 100/20 and IGM 100/21, but these were later assigned to a new genus, Conchoraptor. Another specimen, IGN 100/42, is undoubtedly one of the most famous, with a well-preserved skull and large size. This was referred to Oviraptor by Barsbold in 1981. The specimen was used to represent Oviraptor in most depictions in popular media and in scientific studies of the oviraptorids. However, this specimen with a large cassowary-like crest has been re-examined by scientists and differences were found with the Oviraptor holotype. For this reason it has been removed from the genus Oviraptor, and provisionally placed within the genus Citipati.

Classification

Oviraptor was placed by Osborn along with the ornithomimids, due to its lack of teeth. Osborn also found similarities with the Chirostenotes, which are considered close relatives of Oviraptor. In 1976, Rinchen Barsbold created a new family containing Oviraptor > and their close relatives, conceiving from the genus Oviraptor the type genus for the family Oviraptoridae.

Phylogeny

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

Paleobiology

As its name suggests, Oviraptor was originally presumed to have eaten eggs, based on its association with a fossil nest sample number AMNH FR 6508, which was believed to have belonged to Protoceratops. the palate, would have made a tool for 'egg drilling'. In 1977, Barsbold argued that the strength of its beak would indicate that it was strong enough to crack the shells of molluscs such as clams found in the same geological formation as Oviraptor. These bones are part of the main upper jaw bone or maxilla, which converge in the middle to form a pair of teeth. The remainder of the bony palate, unlike in all other dinosaurs, extends below the jaw line and would have pushed into the space between the toothless lower jaws. A beak, "rhamphotheca," covered the edges of the upper and lower jaws and probably the roof of the mouth, as proposed by Barsbold and Osborn.

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

Pop Culture

Thanks in part to its strange avian appearance, and its reputation as an egg thief, Oviraptor is a common player in popular dinosaur fiction. However, nearly all popular depictions of Oviraptor have actually been based on earlier reconstructions of the high-crested oviraptorid now known as Citipati, not currently recognized specimens of Oviraptor.

A notable example of Oviraptor in fiction is its appearance in James Gurney's book Dinotopia. Because it was not considered an egg predator, Gurney renamed the animal "Ovinutrix," which means "egg keeper."

Oviraptor appears in various movies or television series, such as Disney's Dinosaur, in which he is seen stealing an egg from Iguanodon from which Aladar was born, and in the first episode of the Discovery Channel television series Dinosaur Planet, competing for food with a Velociraptor. Ruby is a young female Oviraptor who meets the young dinosaurs in the television series The Land Before Time.

Oviraptor also appears in various video games, including Dino Stalker and Dino Crisis 2, both displaying the ability to spit venom as Dilophosaurus from Jurassic Park.