Protoceratops

Protoceratops (/ˌproʊtoʊˈsɛrətɒps/; from Greek proto-/πρωτο- "first", cerat-/κερατ- "horn" and -ops/-ωψ "face", meaning "first horned face")[1] 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.

Protoceratops
Temporal range: Late Cretaceous, 75–71 Ma
Carnegie Protoceratops andrewsi
Mounted P. andrewsi skeleton, Carnegie Museum of Natural History
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Clade: Dinosauria
Order: Ornithischia
Infraorder: Neoceratopsia
Parvorder: Coronosauria
Family: Protoceratopsidae
Genus: Protoceratops
Granger & Gregory, 1923
Type species
Protoceratops andrewsi
Granger & Gregory, 1923
Species
  • P. andrewsi Granger & Gregory, 1923
  • P. hellenikorhinus Lambert et al., 2001

Description

Protoceratops scale
Size of P. andrewsi compared to a human

Protoceratops was a quadrupedal dinosaur that was partially characterized by its distinctive neck frill at the back of its skull. The frill itself contained two large parietal fenestrae (holes in the frill), while its cheeks had large jugal bones.[2] The exact size and shape of the neck frill varied by individual; some specimens had short, compact frills, while others had frills nearly half the length of the skull. The frill consists mostly of the parietal bone and partially of the squamosal. Some researchers, including Peter Dodson[3] attribute the different sizes and shapes of these bones to sexual dimorphism, as well as the age of the specimen, at the time of death.

Protoceratops was approximately 1.8 meters (6 ft) in length and 0.6 meters (2 ft) high at the shoulder. A fully grown adult would have weighed less than 400 pounds (180 kg).[4] Smaller specimens are estimated at 23.7 kilograms (52 lb).[5] The large numbers of specimens found in high concentration suggest that Protoceratops lived in herds.[4]

Protoceratops
Restoration of P. andrewsi

Protoceratops was a relatively small dinosaur with a proportionately large skull. Protoceratops appears to have had muscular jaws capable of a powerful bite. These jaws were packed with dozens of teeth, well suited for chewing tough vegetation.[4] The skull consisted of a massive frontal beak, and four pairs of fenestrae (skull openings). The foremost hole, the naris, was considerably smaller than the nostrils seen in later genera. Protoceratops had large orbits (the holes for its eyes), which measured around 50 millimeters in diameter.[3] Behind the eye was a slightly smaller fenestra, known as the "infratemporal fenestra."

Discovery and species

Fighting dinosaurs (2)
Skeletons of P. andrewsi and Velociraptor mongoliensis in combat

Photographer James Blaine Shackelford discovered the first specimen of Protoceratops in the Gobi desert, (Gansu, Inner Mongolia), as part of a 1922 American expedition looking for human ancestors. No early human fossils were found, but the expedition, led by Roy Chapman Andrews, collected many specimens of the genus Protoceratops, along with fossil skeletons of theropods Velociraptor, Oviraptor, and ceratopsian Psittacosaurus.[3]

Walter Granger and W. K. Gregory formally described the type species, P. andrewsi in 1923, the specific name in honor of Andrews. The fossils hail from the Djadochta Formation and date from the Campanian stage of the Upper Cretaceous (dating to between 75 and 71 million years ago).[6] Researchers immediately noted the importance of the Protoceratops finds, and the genus was hailed as the "long-sought ancestor of Triceratops".[3] The fossils were in an excellent state of preservation, with even the sclerotic rings (delicate ocular bones) preserved in some specimens.[3]

In 1971, a fossil was found that captured a Velociraptor mongoliensis clutched around a Protoceratops andrewsi in Mongolia. It is believed that they died simultaneously, while fighting, when they were either surprised by a sand storm or buried when a sand dune collapsed on top of them.[7]

Protoceratops hellenikorhinus 1
P. hellenikorhinus skull

In 1975, Polish paleontologists Teresa Maryanska and Halszka Osmólska described a second species of Protoceratops, also from the Campanian stage of Mongolia, which they named P. kozlowskii.[8] However, the fossils consisted of incomplete juvenile remains, and are now considered synonymous with Bagaceratops rozhdestvenskyi.[9]

In 2001, a second valid species, P. hellenikorhinus, was named from the Bayan Mandahu Formation in Inner Mongolia, China and also dates from the Campanian stage of the Upper Cretaceous. It was notably larger than P. andrewsi, had a slightly different frill, and had more robust jugal horns. The arch of bone over its nostrils had two small nasal horns, and there were no teeth at the front of the snout.[10]

In 2011, a specimen of Protoceratops first uncovered in 1965 was found to be preserved with its own footprint. It is the first example of a dinosaur to be preserved with footprints.[11]

Paleobiology

Reproduction

Amnh protoceratops hatchling1
P. andrewsi hatchling

In the 1920s, Roy Chapman Andrews discovered the first known fossilized dinosaur eggs, in the Gobi Desert of Mongolia. Each egg was about 8 inches long, and newborn hatchlings estimated to have been about a foot in length. Due to the proximity and abundance of Protoceratops, these eggs were believed at the time to belong to this genus.

The contemporary theropod Oviraptor was thought to consume Protoceratops eggs due to the discovery of an Oviraptor skeleton present at a nest. The skull was crushed, and it was speculated that the injury was received by a Protoceratops mother defending her nest from the predator. However, in 1993 Norrell et al. discovered an embryo inside a supposed Protoceratops egg. This embryo, upon close examination, turned out be an Oviraptor;[12] the original find represented Oviraptor brooding behavior rather than a failed attempt at oophagy.

The oogenus Protoceratopsidovum (meaning "Protoceratops egg") was also originally misidentified as belonging to Protoceratops; it is now known to be the eggs of a derived theropod.[13]

Protoceratops growth series
P. andrewsi growth series

In 2011, a nest of 15 young Protoceratops andrewsi was discovered in Mongolia.[14] Stated as being the first Protoceratops nest discovered to date, the discovery suggests that Protoceratops parents might have cared for their young at nests during at least the early stages of childhood. As Protoceratops is a relatively basal member of the ceratopsians, the finding also suggests that other ceratopsians provided care for their young as well.[14]

Studies of lines of growth (i.e. lines of von Ebner) of the teeth in embryonic P. andrewsi suggests plesiomorphically long incubation times, with a minimum incubation time of 83.16 days for P. andrewsi.[15]

Daily activity patterns

The large eyes of Protoceratops has been suggested as evidence for a nocturnal lifestyle.[16] However, subsequent comparisons between the scleral rings of Protoceratops and modern birds and reptiles have indicated a more cathemeral lifestyle, being active throughout the day during short intervals. This suggests that the fight between Protoceratops and the primarily nocturnal Velociraptor indicated by the fighting specimens may have occurred at twilight or under low-light conditions.[17]

Classification

Protoceratops andrewsi (1)
Skull of an adult P. andrewsi

Protoceratops was the first named protoceratopsian and hence gives its name to the family Protoceratopsidae, a group of herbivorous dinosaurs more derived than psittacosaurids, but less derived than ceratopsids. The group is characterized by their similarities to the Ceratopsidae but with more cursorial limb proportions, generally smaller frills, and lack of large horns.

In 1998, Paul Sereno defined Protoceratopsidae as the branch-based clade including "all coronosaurs closer to Protoceratops than to Triceratops." Some studies placed Bagaceratops, Breviceratops, Graciliceratops, Lamaceratops, Magnirostris, Platyceratops, and Serendipaceratops within Protoceratopsidae, but in 2006, Makovicky and Norell published a new phylogeny which removed several genera from Protoceratopsidae; several other phylogenies also exist. Bainoceratops may be synonymous with Protoceratops.[18]

The cladogram below follows the topology from a 2015 analysis by Yiming He, Peter J. Makovicky, Kebai Wang, Shuqing Chen, Corwin Sullivan, Fenglu Han, Xing XuMichael J. Ryan, David C. Evans, Philip J. Currie, Caleb M. Brown and Don Brinkman.[19]

Leptoceratopsidae

Asiaceratops

Cerasinops

Montanoceratops

Ischioceratops

Prenoceratops

Leptoceratops

Udanoceratops

Zhuchengceratops

Gryphoceratops

Unescoceratops

Graciliceratops

Protoceratopsidae

Bagaceratops

Lamaceratops

Breviceratops

Magnirostris

Protoceratops hellenikorhinus

Protoceratops andrewsi

Ajkaceratops

Zuniceratops

Ceratopsidae

Origin of griffin myths

Protoceratops reconstruction
Restoration of P. andrewsi

Folklorist and historian of science Adrienne Mayor of Stanford University has suggested that the exquisitely preserved fossil skeletons of Protoceratops and other beaked dinosaurs, found by ancient Scythian nomads who mined gold in the Tian Shan and Altai Mountains of Central Asia, may have been at the root of the image of the mythical creature known as the griffin. Griffins were described as lion-sized quadrupeds with large claws and a raptor-bird-like beak; they laid their eggs in nests on the ground.[20]

Greek writers began describing the griffin around 675 B.C., at the same time the Greeks first made contact with Scythian nomads. Griffins were described as guarding the gold deposits in the arid hills and red sandstone formations of the wilderness. The region of Mongolia and China where many Protoceratops fossils are found is rich in gold runoff from the neighboring mountains, lending some credence to the theory that these fossils were the basis of griffin myths.[3]

In 2016 this hypothesis was contested, as it ignores pre-Greek gryphon art and accounts.[21]

See also

References

  1. ^ Liddell & Scott (1980). Greek-English Lexicon, Abridged Edition. Oxford University Press, Oxford, UK. ISBN 0-19-910207-4.
  2. ^ Lambert, D. (1993). The Ultimate Dinosaur Book. Dorling Kindersley, New York. pp. 152–167. ISBN 1-56458-304-X.
  3. ^ a b c d e f Dodson, P. (1996). The Horned Dinosaurs. Princeton University Press, Princeton, New Jersey. pp. 200–234. ISBN 0-691-05900-4.
  4. ^ a b c "Protoceratops." In: Dodson, Peter & Britt, Brooks & Carpenter, Kenneth & Forster, Catherine A. & Gillette, David D. & Norell, Mark A. & Olshevsky, George & Parrish, J. Michael & Weishampel, David B. The Age of Dinosaurs. Publications International, LTD. p. 118-119. ISBN 0-7853-0443-6.
  5. ^ Seebacher, F. 2001. A new method to calculate allometric length-mass relationships of dinosaurs. Journal of Vertebrate Paleontology 21 (1). p. 53
  6. ^ Godefroit, Pascal; Currie, Philip J.; Li, Hong; Shang, Chang Yong; Dong, Zhi-ming (2008). "A new species of Velociraptor (Dinosauria: Dromaeosauridae) from the Upper Cretaceous of northern China". Journal of Vertebrate Paleontology. 28 (2): 432–438. doi:10.1671/0272-4634(2008)28[432:ANSOVD]2.0.CO;2.
  7. ^ Carpenter, Ken. (1998). "Evidence of predatory behavior by theropod dinosaurs". Gaia. 15: 135–144. Archived from the original on 2007-11-17. [not printed until 2000]
  8. ^ Maryanska, T.; Osmólska, H. (1975). "Protoceratopsidae (Dinosauria) of Asia". Palaeontologica Polonica. 33: 133–181.
  9. ^ You H. & Dodson, P. 2004. Basal Ceratopsia. In: Weishampel, D.B., Dodson, P., & Osmolska, H. (Eds.). The Dinosauria (2nd Edition). Berkeley: University of California Press. Pp. 478-493.
  10. ^ Lambert, O, Godefroit, P, Li, H, Shang, C.-Y. & Dong, Z.-M. (2001). "A new species of Protoceratops (Dinosauria, Neoceratopsia) from the Late Cretaceous of Inner Mongolia (P. R. China)". Bulletin de l'Institut Royal des Sciences Naturelles de Belgique, Science de la Terre: 5–28.CS1 maint: Multiple names: authors list (link)
  11. ^ BBC Nature - Protoceratops Dinosaur found with its own tracks
  12. ^ http://dallasdino.org/exhibits/dinoworld/Protoceratops.asp Archived February 19, 2006, at the Wayback Machine
  13. ^ Zelenitsky, D. K. And Therrien, F. (2008), "Phylogenetic Analysis Of Reproductive Traits Of Maniraptoran Theropods And Its Implications For Egg Parataxonomy." Palaeontology, 51: 807–816. Doi: 10.1111/J.1475-4983.2008.00770.X
  14. ^ a b Choi, Charles. "15 Infant Dinosaurs Discovered Crowded in Nest". LiveScience.com. November 17, 2011.
  15. ^ Erickson, G.M.; Zelenitsky, D.K.; Kay, D.I.; Norrell, M.A. (2017). "Dinosaur incubation periods directly determined from growth-line counts in embryonic teeth show reptilian-grade development" (PDF). Proceedings of the National Academy of Sciences. doi:10.1073/pnas.1613716114. PMC 5255600.
  16. ^ Longrich, N. (2010). "The Function of Large Eyes in Protoceratops: A Nocturnal Ceratopsian?", In: Michael J. Ryan, Brenda J. Chinnery-Allgeier, and David A. Eberth (eds), New Perspectives on Horned Dinosaurs: The Royal Tyrrell Museum Ceratopsian Symposium, Indiana University Press, 656 pp. ISBN 0-253-35358-0.
  17. ^ Schmitz, L.; Motani, R. (2011). "Nocturnality in Dinosaurs Inferred from Scleral Ring and Orbit Morphology". Science. 332 (6030): 705–8. doi:10.1126/science.1200043. PMID 21493820.
  18. ^ Makovicky, P.J.; Norell, M.A. (2006). "Yamaceratops dorngobiensis, a new primitive ceratopsian (Dinosauria: Ornithischia) from the Cretaceous of Mongolia. 3530:1-42" (PDF). American Museum Novitates. 3530: 1–42. doi:10.1206/0003-0082(2006)3530[1:YDANPC]2.0.CO;2. Retrieved 2008-08-10.
  19. ^ Yiming He; Peter J. Makovicky; Kebai Wang; Shuqing Chen; Corwin Sullivan; Fenglu Han; Xing Xu; Michael J. Ryan; David C. Evans; Philip J. Currie; Caleb M. Brown; Don Brinkman (2015). "A New Leptoceratopsid (Ornithischia, Ceratopsia) with a Unique Ischium from the Upper Cretaceous of Shandong Province, China".
  20. ^ Mayor, A. (2000). The First Fossil Hunters: Paleontology in Greek and Roman Times. Princeton University Press, Princeton, New Jersey. ISBN 0-691-05863-6.
  21. ^ Mark Witton, Why Protoceratops Almost Certainly Wasn't The Inspiration For Griffin Legend

External links

Antorbital fenestra

An antorbital fenestra (plural: fenestrae) is an opening in the skull that is in front of the eye sockets. This skull character is largely associated with archosaurs, first appearing during the Triassic Period. Among extant archosaurs, birds still possess antorbital fenestrae, whereas crocodylians have lost them. The loss in crocodylians is believed to be related to the structural needs of their skulls for the bite force and feeding behaviours that they employ. In some archosaur species, the opening has closed but its location is still marked by a depression, or fossa, on the surface of the skull called the antorbital fossa.

The antorbital fenestra houses a paranasal sinus that is confluent with the adjacent nasal capsule. Although crocodylians walled over their antorbital fenestra, they still retain an antorbital sinus.In theropod dinosaurs, the antorbital fenestra is the largest opening in the skull. Systematically, the presence of the antorbital fenestra is considered a synapomorphy that unites tetanuran theropods as a clade. In contrast, most ornithischian dinosaurs reduce and even close their antorbital fenestrae such as in hadrosaurs and the dinosaur genus Protoceratops. This closure distinguishes Protoceratops from other ceratopsian dinosaurs.

Bagaceratops

Bagaceratops, meaning "small-horned face" (Mongolian Baga = "small"; Greek ceratops = "horn face"), is a genus of ceratopsian dinosaur that lived in what is now Mongolia around 80 million years ago, during the Late Cretaceous. Although emerging late in the reign of the dinosaurs, Bagaceratops had a fairly primitive anatomy and kept the small body size that characterized early ceratopsians.

Bainoceratops

Bainoceratops (Bain: mountain, keras: horn, ops: face) is a genus of ceratopsian dinosaur from the late Campanian in the Late Cretaceous. This ceratopsian was first described by Tereschenko and Alifanov in 2003. Its fossils were found in southern Mongolia.

Breviceratops

Breviceratops (meaning "short horn face") was a herbivorous ceratopsian dinosaur from the Late Cretaceous of Mongolia.

Ceratopsia

Ceratopsia or Ceratopia ( or ; Greek: "horned faces", Κερατόψια) is a group of herbivorous, beaked dinosaurs that thrived in what are now North America, Europe, and Asia, during the Cretaceous Period, although ancestral forms lived earlier, in the Jurassic. The earliest known ceratopsian, Yinlong downsi, lived between 161.2 and 155.7 million years ago. The last ceratopsian species, Triceratops prorsus, became extinct during the Cretaceous–Paleogene extinction event, 66 million years ago.Early members of the ceratopsian group, such as Psittacosaurus, were small bipedal animals. Later members, including ceratopsids like Centrosaurus and Triceratops, became very large quadrupeds and developed elaborate facial horns and frills extending over the neck. While these frills might have served to protect the vulnerable neck from predators, they may also have been used for display, thermoregulation, the attachment of large neck and chewing muscles or some combination of the above. Ceratopsians ranged in size from 1 meter (3 ft) and 23 kilograms (50 lb) to over 9 meters (30 ft) and 9,100 kg (20,100 lb).

Triceratops is by far the best-known ceratopsian to the general public. It is traditional for ceratopsian genus names to end in "-ceratops", although this is not always the case. One of the first named genera was Ceratops itself, which lent its name to the group, although it is considered a nomen dubium today as its fossil remains have no distinguishing characteristics that are not also found in other ceratopsians.

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.

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.

Graciliceratops

Graciliceratops (meaning 'graceful horned face') is a small ceratopsian dinosaur originally described by Teresa Maryańska and Halszka Osmólska in 1975 and referred to Microceratops gobiensis. It was later redescribed as a new genus and species by Paul Sereno in 2000. It is known from the Late Cretaceous period and its fossils were found in Mongolia. Only a partial skeleton has been found. The type (and only known) species is Graciliceratops mongoliensis.

Graciliceratops is known from Shireegiin Gashuun Formation in Mongolia's Gobi Desert, north of the Nemegt Basin. The Shireegiin Gashuun locality is thought to be older than the Djadokhta localities that produced Protoceratops, and is probably early Late Cretaceous in age. The relationships of the genus are unclear, however the frill has large fenestrae bounded by very slender struts. This structure is very similar to that of the later Protoceratops.The skull of the animal measures an estimated twenty centimetres, and the whole animal would have been about the size of a cat. However, the arches and bodies of the vertebrae are not fused, which suggests that the animal was not fully grown when it died. The adult may have approached Protoceratops in size, which grew to around two meters.Like other ceratopsians, Graciliceratops would have been an herbivore, using its powerful beak and shearing teeth to process tough plant matter. Little is known about the flora of the ancient Gobi Desert, and so it is unclear what it would have eaten.

Griffin

The griffin, griffon, or gryphon (Greek: γρύφων, grýphōn, or γρύπων, grýpōn, early form γρύψ, grýps; Latin: gryphus) is a legendary creature with the body, tail, and back legs of a lion; the head and wings of an eagle; and sometimes an eagle's talons as its front feet. Because the lion was traditionally considered the king of the beasts and the eagle the king of birds by the Middle Ages the griffin was thought to be an especially powerful and majestic creature. Since classical antiquity, Griffins were known for guarding treasure and priceless possessions.In Greek and Roman texts, griffins and Arimaspians were associated with gold deposits of Central Asia. Indeed, as Pliny the Elder wrote, "griffins were said to lay eggs in burrows on the ground and these nests contained gold nuggets." Adrienne Mayor, a classical folklorist and historian of science, proposes that the ancient Greek idea and image of the griffin in classical art and literature beginning in the seventh century BC was influenced in part by the fossilized remains of beaked dinosaurs such as Protoceratops observed on the way to gold deposits by nomadic prospectors of ancient Scythia (Central Asia), This hypothesis is necessarily speculative, based on a number of Greek and Latin literary sources and related artworks, beginning with the first written ancient descriptions of griffins in a lost work by Aristeas of Proconnessus (a Greek who traveled to the Altai region between Mongolia and NW China) in the seventh century BC), cited by Aeschylus and Herodotus (ca 450 BC) and ending with Aelian (third century AD). Mayor's suggestion has been contested, with claims that it ignores pre-Mycenaean accounts and bird-lion composites in earlier art that goes far ealier than 7th century BCE.. A multitude of imaginary composite creatures combining features of birds, reptiles, and mammals can be found in ancient Mediterranean and Near Eastern art, including mammals with bird heads in Minoan, Mycenaean,and Egyptian art, but there are no pre-Mycenaean written accounts about Griffins and as Mayor has explained, in fact no written accounts earlier than Herodotus in the fifth century BC survive to tell us anything about imaginary hybrid bird-lion imagery in earlier cultures. Bird-headed mammal images pre-existed the profusion of literary accounts of the "gryps" (Griffin) and accompanying artistic representations that arose in Greece after travelers like Aristeas brought back tales of "Griffins" from Central Asia.

In medieval heraldry, the Griffin became a Christian symbol of divine power and a guardian of the divine.

Ischioceratops

Ischioceratops is an extinct genus of small ceratopsian dinosaur that lived approximately 69 million years ago during the latter part of the Cretaceous Period in what is now China. Ischioceratops was a small sized, moderately-built, ground-dwelling, quadrupedal herbivore, whose total body length has been estimated to be about 2 meters. The ceratopsians were a group of dinosaurs with parrot-like beaks which fed on vegetation and thrived in North America and Asia during the Cretaceous Period, which ended approximately 66 million years ago, at which point they all became extinct. Its name refers to the peculiar shape of the ischiatic bones.Ischioceratops existed in the Wangshi Group during the late Cretaceous. It lived alongside centrosaurines, saurolophines, and tyrannosaurines. The most common creatures in the formation were Sinoceratops and Zhuchengtyrannus.

Jeholosauridae

Jeholosaurids were herbivorous neornithischian dinosaurs from the Cretaceous Period (Aptian - Santonian, with a possible Campanian record) of Asia. The family was first proposed by Han et al. in 2012. The jeholosaurids were defined as those ornithischians more closely related to Jeholosaurus shangyuanensis than to Hypsilophodon foxii, Iguanodon bernissartensis, Protoceratops andrewsi, Pachycephalosaurus wyomingensis, or Thescelosaurus neglectus. The Jeholosauridae includes the type genus Jeholosaurus and Yueosaurus.

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". 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.

Protoceratopsidae

Protoceratopsidae is a family within the group Ceratopsia. The name Protoceratopsidae is derived from Greek for "first horned face". Protoceratopsids have so far been found in the Late Cretaceous, dating to between about 99.6 and 70.6 million years ago. Although Ceratopsians have been found all over the world, protoceratopsids are only known from Asia with most specimens found in China and the Nemegt Basin in Mongolia. As Ceratopsians, protoceratopsids were herbivorous, with constantly replacing tooth batteries made for slicing through plants and a hooked beak for grabbing them. Protoceratopsids were relatively small, between 1-2.5 m in length from head to tail. Their bony frill and horns were much smaller than more derived members of Ceratopsia. Protoceratopsids were likely slow runners and tended to move at a walk or a trot. Their legs may have been straight, creating an upright posture, but there are some theories that they were splayed out to the side, contributing to their slowness. There is evidence that Protoceratops formed groups. Specimens of juveniles and young adults are often found in groups, although adults tend to be solitary. The nature of these groups is not completely known, though herds of young likely formed for protection from predators, and adults are believed to have come together for communal nesting.

Protoceratopsidovum

Protoceratopsidovum is an oogenus of dinosaur egg from Mongolia. Despite its name (which means "eggs of Protoceratops"), it does not represent the eggs of a protoceratopsid, but rather the eggs of maniraptoran theropods.

The Truth About Killer Dinosaurs

The Truth About Killer Dinosaurs is a two-part BBC documentary, presented by Bill Oddie, in which a group of scientists test out the strength of dinosaur weaponry using biomechanics. The first episode determines the winner of a battle between Tyrannosaurus and Triceratops, and the second compares the strength of an ankylosaur and Velociraptor. The programmes were broadcast on BBC 1 in August and September 2005. In the US, The Truth About Killer Dinosaurs was known as Dinosaur Face-Off.

Timeline of ceratopsian research

This timeline of ceratopsian research is a chronological listing of events in the history of paleontology focused on the ceratopsians, a group of herbivorous marginocephalian dinosaurs that evolved parrot-like beaks, bony frills, and, later, spectacular horns. The first scientifically documented ceratopsian fossils were described by Edward Drinker Cope starting in the 1870s; however, the remains were poorly preserved and their true nature was not recognized. Over the next several decades, Cope named several such genera and species. Cope's hated rival, Othniel Charles Marsh, also described ceratopsian remains. In 1887, Marsh mistook a Triceratops horn for one belonging to a new species of prehistoric Bison. Marsh also named the eponymous genus Ceratops in 1888. The next year, he named the most famous ceratopsian, Triceratops horridus. It was the discovery of Triceratops that illuminated the ceratopsian body plan, and he formally named the Ceratopsia in 1890.The early 20th century was a fruitful time for ceratopsian research. In 1907, Hatcher and others published a monograph on ceratopsid anatomy that is still considered the single most significant publication on the topic to date. Many new species were being described, including Centrosaurus, Styracosaurus, and Chasmosaurus. Not long after, the Central Asiatic Expedition led by Roy Chapman Andrews of the American Museum of Natural History discovered the primitive ceratopsians Psittacosaurus and Protoceratops in Mongolia. Protoceratops gained notoriety as the supposed parent of the first fossil dinosaur eggs known to science. One of these supposed Protoceratops nests preserved the skeleton of a new kind of theropod dinosaur, Oviraptor. It was thought to have been preserved after being killed in the act of raiding the Protoceratops nest. This narrative would last until the 1990s, when the "Protoceratops" eggs were determined to belong to Oviraptor itself.Throughout the rest of the century, paleontologists would be occupied with several controversies regarding ceratopsian paleobiology. One concerned the stance of the ceratopsid forelimbs. When Marsh first reconstructed the ceratopsid forelimb, he portrayed it in an erect posture. However, when later researchers like Sternberg and Osborn tried to mount the skeletons, they found that the forelimb bones apparently sprawled despite the hindlimbs standing straight up and down. Later researchers like Robert T. Bakker and Gregory S. Paul attempted to revive the erect reconstruction, but continuing research in the 1990s by researchers like John Ostrom, Peter Dodson, and James Farlow found an intermediate value to be better supported.The original use of the ceratopsids' horns and frills was another long-running controversy in ceratopsian paleontology. Early researchers like Richard Swann Lull thought that bony frills served as the attachment site for enlarged jaw muscles. This explanation was followed by researchers like Russell, Haas, and Ostrom. Sternberg thought the horns of ceratopsians helped defend against predators. In 1961, Davitashvili proposed that ceratopsids used their horns and frills to compete over mates. Farlow and Dodson arrived at the same conclusion in the 1970s, and were followed by Ralph Molnar. Ostrom, who had previously followed the jaw musculature interpretation, came to support this view in 1986. The idea gained further support in the 1990s from researchers like Forster and Sampson.

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.

Velociraptor

Velociraptor (; meaning "swift seizer" in Latin) is a genus of dromaeosaurid theropod dinosaur that lived approximately 75 to 71 million years ago during the latter part of the Cretaceous Period. Two species are currently recognized, although others have been assigned in the past. The type species is V. mongoliensis; fossils of this species have been discovered in Mongolia. A second species, V. osmolskae, was named in 2008 for skull material from Inner Mongolia, China.

Smaller than other dromaeosaurids like Deinonychus and Achillobator, Velociraptor nevertheless shared many of the same anatomical features. It was a bipedal, feathered carnivore with a long tail and an enlarged sickle-shaped claw on each hindfoot, which is thought to have been used to tackle and disembowel prey. Velociraptor can be distinguished from other dromaeosaurids by its long and low skull, with an upturned snout.

Velociraptor (commonly shortened to "raptor") is one of the dinosaur genera most familiar to the general public due to its prominent role in the Jurassic Park motion picture series. In real life, however, Velociraptor was roughly the size of a turkey, considerably smaller than the approximately 2 m (7 ft) tall and 80 kg (180 lb) reptiles seen in the films (which were based on members of the related genus Deinonychus). Today, Velociraptor is well known to paleontologists, with over a dozen described fossil skeletons, the most of any dromaeosaurid. One particularly famous specimen preserves a Velociraptor locked in combat with a Protoceratops.

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