Oviraptor

Oviraptor is a genus of small Mongolian theropod dinosaurs, first discovered by technician George Olsen in an expedition led by Roy Chapman Andrews, and first described by Henry Fairfield Osborn, in 1924. Its name is Latin for 'egg taker' or "egg seizer", 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 4 inches or 10 centimetres 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, when it died at the nest.

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]

Oviraptor
Temporal range: Late Cretaceous, 75 Ma
Oviraptor philoceratops skeleton
Skeletal diagram showing known elements of the holotype specimen (AMNH 6517)
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Clade: Dinosauria
Order: Saurischia
Suborder: Theropoda
Family: Oviraptoridae
Genus: Oviraptor
Osborn, 1924
Type species
Oviraptor philoceratops
Osborn, 1924

Description

Oviraptor size
Size compared to a human
Oviraptor digital1
Artist's restoration

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 theropod 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 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 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.

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.

The Oviraptor has two long, well developed hind limbs, each had three clawed fingers that were used to hold, rip and tear their prey. The Oviraptor had large eyes with bony rings and an unusual cranial crests along with a toothless beak.[5]

Classification

Oviraptor arms
Drawing of the left arm and both hands of type specimen AMNH 6517
Oviraptor skull
Drawing of the skull, 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.[6]

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),[6] but these were later reclassified in the new genus Conchoraptor.[7] 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[8] and came to represent Oviraptor in most popular depictions and in scientific studies of oviraptorids.[9] 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.[10]

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 (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 the upper and lower jaws and probably the palate, as proposed by Barsbold and Osborn.

The discovery of nesting specimens of the related Citipati, 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,[11] implying that the species was at least partially carnivorous.[12]

See also

References

  1. ^ a b c Osborn, H.F. (1924). "Three new Theropoda, Protoceratops zone, central Mongolia." American Museum Novitates, 144: 12 pages, 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. ^ a b 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. ^ "Oviraptor | dinosaur genus". Encyclopedia Britannica. Retrieved 2017-12-13.
  6. ^ a b Barsbold, Rinchen (1976). "(title in Russian)" [A new Late Cretaceous family of small theropods (Oviraptoridae n. fam.) in Mongolia]. Doklady Akademii Nauk SSSR. 226 (3): 685–688.
  7. ^ Barsbold, R. (1986). "Raubdinosaurier Oviraptoren" [in Russian]. In: O.I. Vorob’eva (ed.), Gerpetologičeskie issledovaniâ v Mongol’skoj Narod−noj Respublike, pp. 210–223. Institut èvolûcionnoj morfologii i èkologii životnyh im. A.N. Severcova, Akademiâ nauk SSSR, Moscow.
  8. ^ Barsbold, R. (1981). "Toothless dinosaurs of Mongolia." Joint Soviet-Mongolian Paleontological Expedition Transactions, 15: 28-39. [in Russian].
  9. ^ 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.
  10. ^ Fanti F, Currie PJ, Badamgarav D (2012). "New Specimens of Nemegtomaia from the Baruungoyot and Nemegt Formations (Late Cretaceous) of Mongolia." PLoS ONE, 7(2): e31330. doi:10.1371/journal.pone.0031330
  11. ^ (1995) "Discovering Dinosaurs" U. of California Press
  12. ^ Norell, Clark, Chiappe, and Dashzeveg, (1995). "A nesting dinosaur." Nature, 378: 774-776.
1922 in archaeology

The year 1922 in archaeology involved some significant events.

1922 in science

The year 1922 in science and technology involved some significant events, listed below.

1924 in paleontology

Paleontology or palaeontology (from Greek: paleo, "ancient"; ontos, "being"; and logos, "knowledge") is the study of prehistoric life forms on Earth through the examination of plant and animal fossils. This includes the study of body fossils, tracks (ichnites), burrows, cast-off parts, fossilised feces (coprolites), palynomorphs and chemical residues. Because humans have encountered fossils for millennia, paleontology has a long history both before and after becoming formalized as a science. This article records significant discoveries and events related to paleontology that occurred or were published in the year 1924.

Citipati

Citipati (pronounced [ˈtʃiːt̪ɪpət̪i] in Hindi, meaning 'funeral pyre lord') is a genus of oviraptorid theropod dinosaur from the Late Cretaceous Period of what is now Mongolia (specifically, the Djadokhta Formation of Ukhaa Tolgod, in the Gobi Desert). It is one of the best-known oviraptorids, thanks to a number of well-preserved skeletons, including several specimens found in brooding positions atop nests of eggs. These nesting specimens have helped to solidify the link between non-avian dinosaurs and birds.

The type species, Citipati osmolskae, was described in 2001. A second, as yet unnamed species may also exist. Citipati is often confused with the similar Oviraptor.

Conchoraptor

Conchoraptor (meaning "conch plunderer") is a genus of oviraptorid dinosaur from the late Cretaceous Period of what is now Asia.

Dabrazhin Formation

The Dabrazhin Formation preserves dinosaur fossils in Kazakhstan. There are indeterminate remains of sauropods, nodosaurs, ornithomimosaurs, and other reptiles.

Paleobiota

Kazaklambia

Jaxartosaurus

Archaeornithomimus

Velociraptor

Oviraptor

Coeluroides

Alectrosaurus

Bactrosaurus

Trionyx

Aspideretes

Dinosaur Planet (TV series)

Dinosaur Planet is a four-part American nature documentary that aired on the Discovery Channel as a special-two night event on December 14 and 16, 2003. It is hosted by paleontologist Scott Sampson and narrated by actor Christian Slater. It was released on DVD as a two-disc pack on February 17, 2004, and was also released on VHS around the same time.

The format is similar to Discovery's earlier series When Dinosaurs Roamed America. Each episode tells a fictionalized account of a dinosaur from the Late Cretaceous period. The animals are recreated with computer-generated imagery and composited into present-day filmed locations that approximate prehistoric Earth. Periodic interludes (three in each episode) feature Scott Sampson explaining the scientific findings behind the story, also similar to When Dinosaurs Roamed America, but has improved in quality.

Dinosaur Walk Museum

Dinosaur Walk Museum was a series of attractions that feature life-size sculptures of dinosaurs and replicas of fossils. Branches of the museum were located in Riverhead, New York and Pigeon Forge, Tennessee.

The location in Branson, Missouri closed and relocated, and is now known as Branson Dinosaur Museum.

Djadochta Formation

The Djadochta Formation (sometimes transcribed Djadokhta) is a geological formation situated in central Asia (Gobi Desert), dating from the Late Cretaceous Period. Laid down in the early Campanian, possibly starting in the latest Santonian, it is dated somewhat uncertainly at about 75-71 mya (million years ago). The type locality are the famous "Flaming Cliffs", locally known as Bayanzag ("rich in Haloxylon") or Ulaan-Ereg ("red cliffs").

It preserves an arid habitat of sand dunes, with little freshwater apart from oases and arroyos. In fact, the present-day climate at most Djadochta Formation sites differs little from what it was some 80 mya, except by being somewhat warmer and perhaps a bit less arid then. This is testimony to the fact that the location has long been so far from any major source of evaporation that little rainfall reached it, even before the Himalayas were uplifted which bar clouds from reaching today's Gobi desert.

Most notable fossil discoveries have been the first confirmed dinosaur eggs (a clutch, probably of Oviraptor) and several dinosaur finds, Protoceratops, Pinacosaurus and Velociraptor being the most prominent.

Elongatoolithidae

Elongatoolithidae is an oofamily of fossil eggs, representing the eggs of oviraptorosaurs (with the exception of the avian Ornitholithus). They are known for their highly elongated shape. Elongatoolithids have been found in Europe, Asia, and both North and South America.

Kennalestes

Kennalestes gobiensis is an extinct species of insectivoreous mammal resembling a shrew. It was a common mammal in Mongolia during the Cretaceous period, found in both the Bayan Mandahu Formation and Djadochta Formation. it was found in Mongolia, during the Campanian, so it might've fallen victim to such predators as Velociraptor, Oviraptor and Archaeornithoides.

Maelestes

Maelestes is a prehistoric shrew-like mammal discovered in 1997 in the Gobi Desert. The animal lived in the late Cretaceous Period, around 71-75 million years ago, and was a contemporary of dinosaurs such as Velociraptor and Oviraptor. According to some scientists, the discovery and analysis of this species suggests that true placental mammals appeared near the time the non-avian dinosaurs became extinct 66 million years ago, not much earlier in the Cretaceous as thought by others. However, the presence of an epipubic bone, among other characteristics, place it as a non-placental eutherian.

Nankangia

Nankangia is an extinct genus of caenagnathoid oviraptorosaurian dinosaur known from the Late Cretaceous Nanxiong Formation of Nankang County, Ganzhou City of Jiangxi Province, southeastern China. It contains a single species, Nankangia jiangxiensis. N. jiangxiensis coexisted with at least four other caenagnathoids, including an unnamed oviraptorid, Banji long, Ganzhousaurus nankangensis and Jiangxisaurus ganzhouensis. The relatively short dentary and non-downturned mandibular symphysis of Nankangia suggest that it may have been more herbivorous than carnivorous.

Naturmuseum Senckenberg

The Naturmuseum Senckenberg is a museum of natural history, located in Frankfurt am Main, It is the second largest of its type in Germany. The Senckenberg Museum is particularly popular with children, who enjoy the extensive collection of dinosaur fossils: Senckenberg boasts the largest exhibition of large dinosaurs in Europe. One notable exhibit is a dinosaur fossil with unique, preserved scaled skin. The museum contains a large and diverse collection of birds with 90,000 bird skins 5,050 egg sets 17,000 skeletons and 3,375 spirit specimens. In 2010, almost 517,000 people visited the museum.The building housing the Senckenberg Museum was erected between 1904 and 1907 outside of the center of Frankfurt in the same area as the Johann Wolfgang Goethe University, which was founded in 1914. The museum is owned and operated by the Senckenberg Nature Research Society, which began with an endowment by Johann Christian Senckenberg.

Today, visitors are greeted outside the building by large, life-size recreations of dinosaurs, which are based on the latest scientific theories on dinosaur appearance. Inside, one can follow the tracks of a Titanosaurus, which have been impressed into the floor, towards its skeleton on a sheltered patio.

Attractions include a Diplodocus (donated by the American Museum of Natural History on the occasion of the present museum building's inauguration in 1907), the crested Hadrosaur Parasaurolophus, a fossilized Psittacosaurus with clear bristles around its tail and visible fossilized stomach contents, and an Oviraptor. Big public attractions also include the Tyrannosaurus rex, an original of an Iguanodon, and the museum's mascot, the Triceratops.

Although the dinosaurs attract the most visitors due to their size, the Senckenberg Museum also has a large collection of animal exhibits from every epoch of Earth's history. For example, the museum houses a large number of originals from the Messel pit: field mice, reptiles, fish and a predecessor to the modern horse that lived about 50 million years ago and stood less than 60 cm tall.Unique in Europe is a cast of the famous Lucy, an almost complete skeleton of the upright hominid Australopithecus afarensis. Historical cabinets full of stuffed animals are arranged in the upper levels; among other things one can see one of twenty existing examples of the quagga, which has been extinct since 1883.

Since the remodeling finished in 2003, the new reptile exhibit addresses both the biodiversity of reptiles and amphibians and the topic of nature conservation. An accessible rain forest tree offers views of different zones of the rain forest from the ground to the tree canopy and the habitats to which the exotic reptiles have adapted.

The Senckenberg Museum offers regular evening lectures and tours. One such lecture, by Alfred Wegener on 6 January 1912, was the first public exposition of the theory of Continental Drift

Oviraptoridae

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 enormous. 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.

Pennaraptora

Pennaraptora (Latin penna "bird feather" + raptor "thief", from rapere "snatch"; a feathered bird-like predator) is a clade defined as the most recent common ancestor of Oviraptor philoceratops, Deinonychus antirrhopus, and Passer domesticus (the house sparrow), and all descendants thereof, by Foth et al., 2014. The earliest known definitive member of this clade is Anchiornis, from the late Jurassic period of China, about 160 million years ago.

The clade "Aviremigia" was conditionally proposed along with several other apomorphy-based clades relating to birds by Jacques Gauthier and Kevin de Queiroz in a 2001 paper. Their proposed definition for the group was "the clade stemming from the first panavian with ... remiges and rectrices, that is, enlarged, stiff-shafted, closed-vaned (= barbules bearing hooked distal pennulae), pennaceous feathers arising from the distal forelimbs and tail".

Protoceratops

Protoceratops (; from Greek proto-/πρωτο- "first", cerat-/κερατ- "horn" and -ops/-ωψ "face", meaning "first horned face") is a genus of sheep-sized (1.8 m long) herbivorous ceratopsian dinosaur, from the Upper Cretaceous Period (Campanian stage) of what is now Mongolia. It was a member of the Protoceratopsidae, a group of early horned dinosaurs. Unlike later ceratopsians, however, it was a much smaller creature that lacked well-developed horns and retained some primitive traits not seen in later genera.

Protoceratops had a large neck frill which was likely used as a display site to impress other members of the species. Other hypotheses about its function include protection of the neck and anchoring of jaw muscles, but the fragility of the frill and the poor leverage offered by possible attachment sites here makes these ideas implausible. Described by Walter W. Granger and W.K. Gregory in 1923, Protoceratops was initially believed to be an ancestor of the North American ceratopsians. Researchers currently distinguish two species of Protoceratops (P. andrewsi and P. hellenikorhinus), based in part by their respective sizes.

In the 1920s, Roy Chapman Andrews discovered fossilized eggs in Mongolia that were interpreted as belonging to this dinosaur, but which turned out to be those of Oviraptor.

Rinchenia

Rinchenia is a genus of Mongolian oviraptorid dinosaur from the late Cretaceous Period. The type (and only known) species, Rinchenia mongoliensis, was originally classified as a species within the genus Oviraptor (named Oviraptor mongoliensis by Rinchen Barsbold in 1986), but a re-examination by Barsbold in 1997 found differences significant enough to warrant a separate genus. The name Rinchenia was coined for this new genus by Barsbold in 1997, though he did not describe it in detail, and the name remained a nomen nudum until used by Osmólska et al. in 2004.Rinchenia is known from a single specimen (GI 100/32A) consisting of a complete skull and lower jaw, partial vertebral column, partial forelimbs and shoulder girdle, partial hind limbs and pelvis, and a furcula ("wishbone"). While Rinchenia was about the same size as Oviraptor (about 1.5 meters, or 5 ft long), several features of its skeleton, especially in the skull, show it to be distinct. Its skeleton was more lightly built and less robust than that of Oviraptor, and while the crest of Oviraptor is indistinct because of poor fossil preservation, Rinchenia had a well-preserved, highly developed, dome-like casque which incorporated many bones in the skull that are free of the crest in Oviraptor.

Timeline of oviraptorosaur research

This timeline of oviraptorosaur research is a chronological listing of events in the history of paleontology focused on the oviraptorosaurs, a group of beaked, bird-like theropod dinosaurs. The early history of oviraptorosaur paleontology is characterized by taxonomic confusion due to the unusual characteristics of these dinosaurs. When initially described in 1924 Oviraptor itself was thought to be a member of the Ornithomimidae, popularly known as the "ostrich" dinosaurs, because both taxa share toothless beaks. Early caenagnathid oviraptorosaur discoveries like Caenagnathus itself were also incorrectly classified at the time, having been misidentified as birds.The hypothesis that caenagnathids were birds was questioned as early as 1956 by Romer, but not corrected until Osmolska formally reclassified them as dinosaurs in 1976. Meanwhile, the classification of Oviraptor as an ornithomimid persisted unquestioned by researchers like Romer and Steel until the early 1970s when Dale Russell argued against the idea in 1972. In 1976 when Osmolska recognized Oviraptor's relationship with the Caenagnathids, she also recognized that it was not an ornithomimid and reclassified it as a member of the former family. However, that same year Rinchen Barsbold argued that Oviraptor belonged to a distinct family he named the Oviraptoridae and he also formally named the Oviraptorosauria later in the same year.Like their classification, the paleobiology of oviraptorosaurs has been subject to controversy and reinterpretation. The first scientifically documented Oviraptor skeleton was found lying on a nest of eggs. Because its powerful parrot-like beak appeared well-adapted to crushing hard food items and the eggs were thought to belonged to the neoceratopsian Protoceratops, oviraptorosaurs were thought to be nest-raiders that preyed on the eggs of other dinosaurs. In the 1980s, Barsbold proposed that oviraptorosaurs used their beaks to crack mollusk shells as well. In 1993, Currie and colleagues hypothesized that small vertebrate prey may have also been part of the oviraptorosaur diet. Not long after, fossil embryonic remains cast doubt on the popular reconstruction of oviraptorosaurs as egg thieves when it was discovered that the "Protoceratops" eggs that Oviraptor was thought to be "stealing" actually belonged to Oviraptor itself. The discovery of additional Oviraptor preserved on top of nests in lifelike brooding posture firmly established that oviraptorosaurs had been "framed" as egg thieves and were actually caring parents incubating their own nests.

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