Smaller than other dromaeosaurids likeDeinonychus andAchillobator,Velociraptor was about 1.5–2.07 m (4.9–6.8 ft) long with a body mass around 14.1–19.7 kg (31–43 lb). It nevertheless shared many of the sameanatomical features. It was abipedal,featheredcarnivore with a long tail and an enlarged sickle-shapedclaw on each hindfoot, which is thought to have been used to tackle and restrainprey.Velociraptor can be distinguished from other dromaeosaurids by its long and lowskull, with an upturned snout.
Velociraptor (commonly referred to as "raptor") is one of the dinosaur genera most familiar to the general public due to itsprominent role in theJurassic Park films. In reality, however,Velociraptor was roughly the size of aturkey, considerably smaller than the approximately 2 m (6.6 ft) tall and 90 kg (200 lb) reptiles seen in the novels and films (which were based on members of the related genusDeinonychus). Today,Velociraptor is well known topaleontologists, with over a dozen described fossil skeletons.One particularly famous specimen preserves aVelociraptor locked in combat with aProtoceratops.
Line diagram ofV. mongoliensis holotype skull and associated manual ungual
During anAmerican Museum of Natural History expedition to theFlaming Cliffs (Bayn Dzak or Bayanzag) of theDjadochta Formation,Gobi Desert, on 11 August 1923, Peter Kaisen discovered the firstVelociraptor fossil known to science—a crushed but complete skull, associated with one manual claw and adjoining phalanges (AMNH 6515). In 1924, museum presidentHenry Fairfield Osborn designated the skull and part of the manus as thetype specimen of his new genus,Velociraptor. This name is derived from theLatin wordsvelox ('swift') andraptor ('robber' or 'plunderer') and refers to the animal'scursorial nature and carnivorous diet. Osborn named the type speciesV. mongoliensis after its country of origin.[3] Earlier that year, Osborn had informally mentioned the animal in a popular press article, under the name "Ovoraptor djadochtari" (not to be confused with the similarly namedOviraptor),[4] eventually changed intoV. mongoliensis during its formal description.[3]
While North American teams were shut out ofcommunist Mongolia during theCold War, expeditions bySoviet andPolish scientists, in collaboration with Mongolian colleagues, recovered several more specimens ofVelociraptor. The most famous is part of the "Fighting Dinosaurs" specimen (MPC-D 100/25; formerly IGM, GIN, or GI SPS), discovered by a Polish-Mongolian team in 1971. The fossil preserves aVelociraptor in battle against aProtoceratops.[5][6][7] It is considered a national treasure of Mongolia, and in 2000 it was loaned to the American Museum of Natural History inNew York City for a temporary exhibition.[8]
Between 1988 and 1990, a jointChinese-Canadian team discoveredVelociraptor remains in northern China.[9] American scientists returned to Mongolia in 1990, and a joint Mongolian-American expedition to the Gobi, led by the American Museum of Natural History and theMongolian Academy of Sciences, turned up several well-preserved skeletons.[10][11] One such specimen, MPC-D 100/980, was nicknamed "Ichabodcraniosaurus" by Norell's team because the fairly complete specimen was found without its skull (an allusion to theWashington Irving characterIchabod Crane).[12] While Norell and Makovicky provisionally considered it a specimen ofVelociraptor mongoliensis,[10] it was named as a new speciesShri devi in 2021.[13]
In 1999,Rinchen Barsbold andHalszka Osmólska reported a juvenileVelociraptor specimen (GIN or IGM 100/2000), represented by a complete skeleton including the skull of a young individual. It was found at the Tugriken Shireh locality of the Djadochta Formation during the context of the Mongolian-Japanese Palaeontological Expeditions. The coauthors stated that detailed descriptions of this and other specimens would be published at a later date.[14]
Additional species
Velociraptorine skulls, B, D, E areV. mongoliensis, C isV sp., and F isV. osmolskae (known parts in gray)
Maxillae and alacrimal (the main tooth-bearing bones of the upper jaw, and the bone that forms the anterior margin of the eye socket, respectively) recovered from theBayan Mandahu Formation in 1999 by the Sino-Belgian Dinosaur Expeditions were found to pertain toVelociraptor, but not to the type speciesV. mongoliensis.Pascal Godefroit and colleagues named these bonesV. osmolskae (for Polish paleontologistHalszka Osmólska) in 2008.[15] However, the 2013 study noted that while "the elongate shape of the maxilla inV. osmolskae is similar to that ofV. mongoliensis," phylogenetic analysis found it to be closer toLinheraptor, making the genusparaphyletic; thus,V. osmolskae might not actually belong to the genusVelociraptor and requires reassessment.[16]
Paleontologists Mark A. Norell and Peter J. Makovicky in 1997 described new and well preserved specimens ofV. mongoliensis, namely MPC-D 100/985 collected from the Tugrik Shireh locality in 1993, and MPC-D 100/986 collected in 1993 from the Chimney Buttes locality. The team briefly mentioned another specimen, MPC-D 100/982, which by the time of this publication remained undescribed.[11] In 1999 Norell and Makovicky provided more insights into the anatomy ofVelociraptor with additional specimens. Among these, MPC-D 100/982 was partially described and figured, and referred toV. mongoliensis mainly based on cranial similarities with the holotype skull, although they stated that differences were present between the pelvic region of this specimen and otherVelociraptor specimens. This relatively well-preserved specimen including the skull was discovered and collected in 1995 at the Bayn Dzak locality (specifically at the "Volcano" sub-locality).[10] Martin Kundrát in a 2004 abstract compared the neurocranium of MPC-D 100/982 to anotherVelociraptor specimen, MPC-D 100/976. He concluded that the overall morphology of the former was more derived (advanced) than the latter, suggesting that they could represent distinct taxa.[17]
Velociraptor specimen MPC-D 100/982, possibly a new species
Mark J. Powers in his 2020 master thesis fully described MPC-D 100/982, which he concluded to represent a new and third species ofVelociraptor. This species, which he considered distinct, was stated to mainly differ from otherVelociraptor species in having a shallow maxilla morphology.[18] Powers and colleagues also in 2020 usedmorphometric analyses to compare several dromaeosaurid maxillae, and found the maxilla of MPC-D 100/982 to strongly differ from specimens referred toVelociraptor. They indicated that this specimen, based on these results, represents a different species.[19] In 2021 Powers with team usedPrincipal Component Analysis to separate dromaeosaurid maxillae, most notably finding that MPC-D 100/982 falls outside the instraspecific variability ofV. mongoliensis, arguing for a distinct species. They considered that bothV. mongoliensis and this new species were ecologically separated based on their skull anatomy.[20] The team in another 2021 abstract reinforced again the species-level separation, noting that additional differences can be found in the hindlimbs.[21]
Description
Velociraptor specimens compared in size to a 1.8 m (5 ft 11 in) tallhuman
Velociraptor was a small to medium-sizeddromaeosaurid, with adults measuring between 1.5–2.07 m (4.9–6.8 ft) long, approximately 0.5 m (1.6 ft) high at the hips,[22][23] and weighing about 14.1–19.7 kg (31–43 lb).[24][25]
Prominentquill knobs—attachment site of "wing" feathers and direct indicator of afeather covering—have been reported from theulna of a singleVelociraptor specimen (IGM 100/981), which represents an animal of estimated 1.5 m (4.9 ft) long and 15 kg (33 lb) in weight. The spacing of 6 preserved knobs suggests that 8 additional knobs may have been present, giving a total of 14 quill knobs that developed largesecondaries ("wing" feathers stemming from the forearm).[26] However, the specimen number has been corrected to IGM 100/3503 and its referral toVelociraptor may require reevaluation, pending further study.[27] Nevertheless, there is strongphylogenetic evidence from other dromaeosaurid relatives that indicates the presence of feathers inVelociraptor, including dromaeosaurids such asDaurlong,[28]Microraptor,[29] orZhenyuanlong.[30]
Skull
Life restoration
The skull ofVelociraptor was rather elongated and grew up to 23 cm (9.1 in) long. It was uniquely up-curved at the snout region, concave on the upper surface, and convex on the lower surface. The snout, which occupied about 60% of the entire skull length, was notably narrow and mainly formed by the nasal, premaxilla, and maxilla bones. Thepremaxilla was the anteriormost bone in the skull, and it was longer than taller. While its posterior end joined the nasal, the main body of the premaxilla touched the maxilla. Themaxilla was nearly triangular in shape and the largest element of the snout. On its center or main body, there was a depression developing a small oval to circular-shaped hole, called maxillary fenestra. Though in front of this fenestra were two small openings, referred to as promaxillary fenestrae. The posterior border of the maxilla formed (predominantly) the antorbital fenestra, one of the several large holes in the skull. Both premaxilla and maxilla had severalalveoli (tooth sockets) on their bottom surfaces. Above the maxilla and making contact with the premaxilla, there was thenasal bone. It was a thin/narrow and elongated bone contributing to the top surface of the snout. Together, both premaxilla and nasal bones gave form to the naris or narial fenestra (nostril opening), which was relatively large and circular. The posterior end of the nasal was joined by the frontal and lacrimal bones.[31][14]
Skull of MPC-D 100/25 (Fighting Dinosaurs individual), in lateral (A-C), top (B), bottom (D-E), and posterior (E) views
The back or posterior region of the skull was built by the frontal, lacrimal, postorbital, jugal, parietal, quadrate, and quadratojugal bones. Thefrontal was large element, having a vaguely rectangular shape when seen from above. On its posterior end, this bone was in contact with theparietal, and such elements were the main bodies of theskull roof. Thelacrimal was a T-shaped bone and its main body was thin and delicated. Its lower end meet thejugal (often called cheek bone), which was a large, sub-triangular-shaped element. Its lower border was notably straight/horizontal. Thepostorbital was located just above the jugal: a stocky and strongly T-shaped bone. As a whole, the orbit or orbital fenestra (eye socket)—formed by the lacrimal, jugal, frontal, and postorbital—was large and near circular in shape, being longer than taller. When seen from above, a pair of large and markedly rounded holes were present near the rear of the skull (the temporal fenestrae), whose main components were the postorbital and squamosal. Behind the jugal, an inverted T-shaped bone (also seen in other dromaeosaurids), known as thequadratojugal, was developed. While the upper end of the quadratojugal joined thesquamosal, an irregularly-shaped element, its inner side meet thequadrate. The latter was of great importance for the articulation with the lower jaw. The posteriormost bone was theoccipital bone and its projection theoccipital condyle: a rounded and bulbous protuberance that meet the first vertebra of the neck.[31][14]
V. mongoliensis holotype skull (right), rostrum (left), and dentary (bottom)
The lower jaw ofVelociraptor comprised mainly the dentary, splenial, angular, surangular, and articular bones. Thedentary was a very long, weakly curved, and narrow element that developed several alveoli on its top surface. On its posterior end, it meet thesurangular. It had a small hole near its posterior end, called surangular foramen or fenestra. Both bones were the largest elements of the lower jaw ofVelociraptor, contributing to virtually its entire length. Below them were the smallersplenial andangular, closely articulated to each other. Thearticular, located on the inner side of the surangular, was a small element that joined the quadrate of the upper skull, enabling the articulation with the lower jaw. An elongated, near oval-shaped hole was developed in the center of the lower jaw (the mandibular fenestra), and it was produced by the joint of the dentary, surangular, and angular bones.[31][14]
The teeth ofVelociraptor were fairlyhomodont (equal in shape) and had severaldenticles (serrations), each more strongly serrated on the back edge than the front. The premaxilla had 4 alveoli (meaning that 4 teeth were developed), and the maxilla had 11 alveoli. At the dentary, between 14–15 alveoli were present. All teeth present at the premaxilla were poorly curved, and the two first teeth were the longest, with the second having a characteristic large size. The maxillary teeth were more slender, recurved, and most notably, the lower end was strongly more serrated than the upper one.[31][14]
Postcranial skeleton
Line diagram of the pes ofV. mongoliensis (MPC-D 100/985)
The arm ofVelociraptor was formed by thehumerus (upper arm bone),radius andulna (forearm bones), andmanus (hand).Velociraptor, like other dromaeosaurids, had a large manus with three elongateddigits (fingers), which ended up in strongly curved unguals (claw bones) that were similar in construction and flexibility to the wing bones of modernbirds. The second digit was the longest of the three digits present, while the first was shortest. The structure of thecarpal (wrist) bones preventedpronation of the wrist and forced the manus to be held with thepalmar surface facing inward (medially), not downward. Thepes (foot) anatomy ofVelociraptor consisted of the metatarsus—a large element composed of three metatarsals of which the first one was extremely reduced in size—and four digits that developed large unguals. The first digit, as in other theropods, was a smalldewclaw. The second digit, for whichVelociraptor is most famous, was highly modified and held retracted off the ground, which causedVelociraptor and other dromaeosaurids to walk on only their third and fourth digits. It bore a relatively large, sickle-shaped claw, typical of dromaeosaurid andtroodontid dinosaurs. This enlarged claw, which could grow to over 6.5 cm (2.6 in) long around its outer edge, was most likely a predatory device used to restrain struggling prey.[11][10]
As in other dromaeosaurs,Velociraptor tails hadprezygapophyses (long bony projections) on the upper surfaces of thevertebrae, as well asossifiedtendons underneath. The prezygapophyses began on the tenth tail (caudal) vertebra and extended forward to brace four to ten additional vertebrae, depending on position in the tail. These were once thought to fully stiffen the tail, forcing the entire tail to act as a single rod-like unit. However, at least one specimen has preserved a series of intact tail vertebrae curved sideways into anS-shape, suggesting that there was considerably more horizontal flexibility than once thought.[11][10][32]
Classification
Velociraptor is a member of the groupEudromaeosauria, aderived sub-group of the larger family Dromaeosauridae. It is often placed within its own subfamily,Velociraptorinae. Inphylogenetic taxonomy, Velociraptorinae is usually defined as "all dromaeosaurs more closely related toVelociraptor than toDromaeosaurus." However, dromaeosaurid classification is highly variable. Originally, the subfamily Velociraptorinae was erected solely to containVelociraptor.[5] Other analyses have often included other genera, usuallyDeinonychus andSaurornitholestes,[33] and more recentlyTsaagan.[34] Several studies published during the 2010s, including expanded versions of the analyses that found support for Velociraptorinae, have failed to resolve it as a distinct group, but rather have suggested it is a paraphyletic grade which gave rise to theDromaeosaurinae.[35][36]
When first described in 1924,Velociraptor was placed in the familyMegalosauridae, as was the case with most carnivorous dinosaurs at the time (Megalosauridae, likeMegalosaurus, functioned as a sort of 'wastebin' taxon, where many unrelated species were grouped together).[3] As dinosaur discoveries multiplied,Velociraptor was later recognized as a dromaeosaurid. All dromaeosaurids have also been referred to the familyArchaeopterygidae by at least one author (which would, in effect, makeVelociraptor a flightless bird).[37] In the past, other dromaeosaurid species, includingDeinonychus antirrhopus andSaurornitholestes langstoni, have sometimes been classified in the genusVelociraptor. SinceVelociraptor was the first to be named, these species were renamedVelociraptor antirrhopus andV. langstoni.[22] As of 2008,[update] the only currently recognized species ofVelociraptor areV. mongoliensis[14][37][38] andV. osmolskae.[15] However, several studies have found "V."osmolskae to be distantly related toV. mongoliensis.[39][40]
Size ofVelociraptor (2) compared with other dromaeosaursComparison of some members ofVelociraptorinae, featuringLinheraptor,Tsaagan andVelociraptor
Below are the results for the Eudromaeosauriaphylogeny based on thephylogenetic analysis conducted by James G. Napoli and team in 2021 during the description ofKuru, showing the position ofVelociraptor:[27]
In 2007 Alan H. Turner and colleagues reported the presence of sixquill knobs in the ulna of a referredVelociraptor specimen (IGM 100/981) from the Ukhaa Tolgod locality of theDjadochta Formation. Turner and colleagues interpreted the presence of feathers onVelociraptor as evidence against the idea that the larger, flightlessmaniraptorans lost their feathers secondarily due to larger body size. Furthermore, they noted that quill knobs are almost never found in flightless bird species today, and that their presence inVelociraptor (presumed to have been flightless due to its relatively large size and short forelimbs) is evidence that the ancestors of dromaeosaurids could fly, makingVelociraptor and other large members of this family secondarily flightless, though it is possible the large wing feathers inferred in the ancestors ofVelociraptor had a purpose other than flight. The feathers of the flightlessVelociraptor may have been used for display, for covering their nests while brooding, or for added speed and thrust when running up inclined slopes.[26]
Because of the presence of another dromaeosaurid in Ukhaa Tolgod,Tsaagan, Napoli and team have noted that the referral of this specimen toVelociraptor is currently subject to reexamination.[27]
Senses
Examinations of the endocranium ofVelociraptor indicate that it was able to detect and hear a wide range of sound frequencies (2,368–3,965 Hz) and could track prey with ease as a result. The endocranium examinations also further cemented the theory that the dromaeosaur was an agile, swift predator. Fossil evidence suggestingVelociraptor scavenged also indicates that it was an opportunistic and actively predatory animal, feeding on carrion during times of drought or famine, if in poor health, or depending on the animal's age.[41]
Feeding
Isolated tooth of ZPAL MgD-I/97a
In 2020, Powers and colleagues re-examined themaxillae of severaleudromaeosaur taxa concluding that most Asian and North American eudromaeosaurs were separated by snout morphology and ecological strategies. They found the maxilla to be a reliable reference when inferring the shape of thepremaxilla and overallsnout. For instance, most Asian species have elongated snouts based on the maxilla (namelyvelociraptorines), indicating a selective feeding inVelociraptor and relatives, such as picking up small, fast prey. In contrast, most North American eudromaeosaurs, mostly dromaeosaurines, feature a robust and deep maxillar morphology. However, the large dromaeosurineAchillobator is a unique exception to Asian taxa with its deep maxilla.[42]
Manabu Sakamoto in 2022 performed a Bayesian phylogenetic predictive modelling framework for estimating jaw muscle parameters and bite forces of several extinct archosaurs, based on skull widths and phylogenetic relationships between groups. Among studied taxa,Velociraptor was scored with a bite force of 304N, which was lower than that of other dromaeosaurids such asDromaeosaurus (885 N) orDeinonychus (706 N).[43]
Predatory behavior
The "Fighting Dinosaurs" specimen ofV. mongoliensis andProtoceratops andrewsi and restoration of same
The "Fighting Dinosaurs" specimen, found in 1971, preserves aVelociraptor mongoliensis andProtoceratops andrewsi in combat and provides direct evidence of predatory behavior. When originally reported, it was hypothesized that the two animals drowned.[7] However, as the animals were preserved in ancient sand dune deposits, it is now thought that the animals were buried in sand, either from a collapsing dune or in asandstorm. Burial must have been extremely rapid, judging from the lifelike poses in which the animals were preserved. Parts of theProtoceratops are missing, which has been seen as evidence ofscavenging by other animals.[44] Comparisons between thescleral rings ofVelociraptor,Protoceratops, and modern birds and reptiles indicates thatVelociraptor may have beennocturnal, whileProtoceratops may have beencathemeral, active throughout the day during short intervals, suggesting that the fight may have occurred at twilight or during low-light conditions.[45]
Size comparison of the Fighting Dinosaurs
The distinctive claw, on the second digit of dromaeosaurids, has traditionally been depicted as a slashing weapon; its assumed use being to cut anddisembowel prey.[46] In the "Fighting Dinosaurs" specimen, theVelociraptor lies underneath, with one of its sickle claws apparently embedded in the throat of its prey, while the beak ofProtoceratops is clamped down upon the right forelimb of its attacker. This suggestsVelociraptor may have used its sickle claw to pierce vital organs of the throat, such as thejugular vein,carotid artery, ortrachea (windpipe), rather than slashing the abdomen. The inside edge of the claw was rounded and not unusually sharp, which may have precluded any sort of cutting or slashing action, although only the bony core of the claw is preserved. The thick abdominal wall ofskin andmuscle of large prey species would have been difficult to slash without a specialized cutting surface.[44] The slashinghypothesis was tested during a 2005BBC documentary,The Truth About Killer Dinosaurs. The producers of the program created an artificialVelociraptor leg with a sickle claw and used apork belly to simulate the dinosaur's prey. Though the sickle claw did penetrate the abdominal wall, it was unable to tear it open, indicating that the claw was not used to disembowel prey.[47]
Remains ofDeinonychus, a closely related dromaeosaurid, have commonly been found in aggregations of several individuals.Deinonychus has also been found in association with the large ornithopodTenontosaurus, which has been cited as evidence of cooperative (pack) hunting.[48][49] However, the only solid evidence for social behavior of any kind among dromaeosaurids comes from a Chinese trackway which shows six individuals of a large species moving as a group.[50] Although many isolated fossils ofVelociraptor have been found in Mongolia, none were closely associated with other individuals.[38] Therefore, whileVelociraptor is commonly depicted as apack hunter, as inJurassic Park, there is only limited fossil evidence to support this theory for dromaeosaurids in general and none specific toVelociraptor itself. Dromeosaur footprints in China suggest that a few other raptor genera may have hunted in packs, but there have been no conclusive examples of pack behavior found.[51][52]
V. mongoliensis restraining anoviraptorosaur with its sickle claws
In 2011, Denver Fowler and colleagues suggested a new method by which dromaeosaurs likeVelociraptor and similar dromaeosaurs may have captured and restrained prey. This model, known as the "raptor prey restraint" (RPR) model of predation, proposes that dromaeosaurs killed their prey in a manner very similar to extantaccipitridbirds of prey: by leaping onto their quarry, pinning it under their body weight, and gripping it tightly with the large, sickle-shaped claws. These researchers proposed that, like accipitrids, the dromaeosaur would then begin to feed on the animal while it was still alive, and prey death would eventually result from blood loss and organ failure. This proposal is based primarily on comparisons between the morphology and proportions of the feet and legs of dromaeosaurs to several groups of extant birds of prey with known predatory behaviors. Fowler found that the feet and legs of dromaeosaurs most closely resemble those ofeagles andhawks, especially in terms of having an enlarged second claw and a similar range of grasping motion. The shortmetatarsus and foot strength, however, would have been more similar to that ofowls. The RPR method of predation would be consistent with other aspects ofVelociraptor's anatomy, such as their unusual jaw and arm morphology. The arms, which could exert a lot of force but were likely covered in long feathers, may have been used as flapping stabilizers for balance while atop a struggling prey animal, along with the stiff counterbalancing tail. The jaws, thought by Fowler and colleagues to be comparatively weak, would have been useful for row saw motion bites like the modern dayKomodo dragon, which also has a weak bite, to finish off its prey if the kicks were not powerful enough. These predatory adaptations working together may also have implications for theorigin of flapping inparavians.[32]
Scavenging behavior
In 2010, Hone and colleagues published a paper on their 2008 discovery of shed teeth of what they believed to be aVelociraptor near a tooth-marked jaw bone of what they believed to be aProtoceratops in the Bayan Mandahu Formation. The authors concluded that the find represented "late-stage carcass consumption byVelociraptor" as the predator would have eaten other parts of a freshly killedProtoceratops before biting in the jaw area. The evidence was seen as supporting the inference from the "Fighting Dinosaurs" fossil thatProtoceratops was part of the diet ofVelociraptor.[53]
In 2012, Hone and colleagues published a paper that described aVelociraptor specimen with a long bone of anazhdarchidpterosaur in its gut. This was interpreted as showing scavenging behaviour.[54]
In a 2024 study by Tse, Miller, and Pittman et al., focusing on the skull morphology and bite forces of various dromaeosaurids, it was discovered thatVelociraptor had high bite force resistance compared to other dromaeosaurids such asDromaeosaurus itself andDeinonychus, the latter of which was much larger. It is theorized by the authors that high bite force resistance was an adaptation towards obtaining food through scavenging more often than through active predation inVelociraptor.[55]
Metabolism
3D scan and nasal cavity reconstruction ofV. mongoliensis skull MPC-D 100/54
Velociraptor waswarm-blooded to some degree, as it required a significant amount of energy to hunt. Modern animals that possess feathery or furry coats, likeVelociraptor did, tend to be warm-blooded, since these coverings function as insulation. However, bone growth rates in dromaeosaurids and some early birds suggest a more moderatemetabolism, compared with most modern warm-blooded mammals and birds. Thekiwi is similar to dromaeosaurids in anatomy, feather type, bone structure and even the narrow anatomy of the nasal passages (usually a key indicator of metabolism). The kiwi is a highly active, if specialized, flightless bird, with a stable body temperature and a fairly low resting metabolic rate, making it a good model for the metabolism of primitive birds and dromaeosaurids.[37]
In 2023, Seishiro Tada and team examined the nasal cavities ofectotherm (cold-blooded) orendotherm (warm-blooded) species, in order to evaluate thethermoregulatory physiology of non-avian dinosaurs compared to these groups. They found that the size of the nasal cavity relative to the head size of extant endotherms is larger than those of extant ectotherms, and among taxa,Velociraptor was recovered below the extant endotherms level by reconstructing its nasal respiratory cavity. Tada with team suggested thatVelociraptor and most other non-avian dinosaurs may not have possessed a fully or well-developed nasal thermoregulation apparatus as modern endothermic animals do.[56]
Norell with colleagues in 1995 reported oneV. mongoliensis skull bearing two parallel rows of small punctures on its frontal bones that, upon closer examination, match the spacing and size ofVelociraptor teeth. They suggested that the wound was likely inflicted by anotherVelociraptor during afight within the species. Because its bone structure shows no sign ofhealing near the bite wounds and the overall specimen was not scavenged, this individual was likely killed by this fatal wound.[57] In 2001 Molnar and team noted that this specimen is MPC-D 100/976 hailing from the Tugrik Shireh locality, which has also yielded the Fighting Dinosaurs specimen.[58]
In 2012 David Hone and team reported another injuredVelociraptor specimen (MPC-D 100/54, roughly a sub-adult individual) found with the bones of anazhdarchid pterosaur within its stomach cavity, was carrying or recovering from an injury sustained to one broken rib. From evidence on the pterosaur bones, which were devoid of pitting or deformations from digestion, theVelociraptor died shortly after, possibly from the earlier injury. Nevertheless, the team noted that this broken ribs shows signs of bone healing.[54]
Paleoenvironment
Bayan Mandahu Formation
Restoration of relatedLinheraptor in paleoenvironment
In bothBayan Mandahu and Djadochta formations many of the same genera were present, though they varied at the species level. These differences in species composition may be due a natural barrier separating the two formations, which are relatively close to each other geographically.[15] However, given the lack of any known barrier which would cause the specific faunal compositions found in these areas, it is more likely that those differences indicate a slight time difference.[59]
The Djadochta Formation is separated into a lower Bayn Dzak Member and upper Turgrugyin Member.V. mongoliensis is known from both members, represented by numerous specimens.[61] The Bayn Dzak Member (mainly Bayn Dzak locality) has yielded the oviraptoridOviraptor; ankylosauridPinacosaurus grangeri; protoceratopsidProtoceratops andrewsi; and troodontidSaurornithoides.[3][61] The younger Turgrugyin Member (mainly Tugriken Shireh locality) has produced the birdElsornis; dromaeosauridMahakala: ornithomimidAepyornithomimus; and protoceratopsidProtoceratops andrewsi.[64][65]
V. mongoliensis has been found at many of the most famous and prolific Djadochta localities. The type specimen was discovered at theFlaming Cliffs site (sublocality of the larger Bayn Dzak locality/region),[3] while the "Fighting Dinosaurs" were found at the Tugrik Shire locality (also known as Tugrugeen Shireh and many other spellings).[6] The latter is notorious for its exceptionalin situ fossil preservation. Based on deposits (such as structureless sandstones), it has been concluded that a large number of specimens were buried alive during powerful sand-bearing events, common to these paleoenvironments.[66]
The "Dinosaur Input Device"Velociraptor used for creating some of theCGI effects inJurassic Park (left), and the design from theJurassic World trilogy, Hong Kong (right)
Velociraptor is commonly perceived as a vicious and cunning killer thanks to their portrayal in the 1990 novelJurassic Park byMichael Crichton and its 1993film adaptation, directed bySteven Spielberg. The"raptors" portrayed inJurassic Park were actually modeled after the closely relateddromaeosauridDeinonychus. Paleontologists in both the novel and film excavate a skeleton inMontana, far from the central Asian range ofVelociraptor but characteristic of theDeinonychus range.[67] Crichton met with the discoverer ofDeinonychus,John Ostrom, several times atYale University to discuss details of the animal's possible range of behaviors and appearance. Crichton at one point apologetically told Ostrom that he had decided to use the nameVelociraptor in place ofDeinonychus because the former name was "more dramatic." According to Ostrom, Crichton stated that theVelociraptor of the novel was based onDeinonychus in almost every detail, and that only the name had been changed. TheJurassic Park filmmakers also requested all of Ostrom's published papers onDeinonychus during production.[68] They portrayed the animals with the size, proportions, and snout shape ofDeinonychus rather thanVelociraptor.[69][70]
Production onJurassic Park began before the discovery of the large dromaeosauridUtahraptor was made public in 1991, but as Jody Duncan wrote about this discovery: "Later, after we had designed and built the raptor, there was a discovery of a raptor skeleton in Utah, which they labeled 'super-slasher.' They had uncovered the largest Velociraptor to date and it measured five-and-a-half-feet tall, just like ours. So we designed it, we built it, and then they discovered it. That still boggles my mind."[69] Spielberg's name was briefly considered for naming of the new dinosaur in exchange for funding of field work, but no agreement was reached.[71]
Jurassic Park and its sequelThe Lost World: Jurassic Park were released before the discovery that dromaeosaurs had feathers, so theVelociraptor in both films were depicted as scaled and featherless. ForJurassic Park III, the maleVelociraptor was given quill-like structures along the back of the head and neck, but these structures do not resemble the feathers thatVelociraptor would have had in reality due to reasons of continuity.[72] TheJurassic World sequel trilogy ignored the feathers ofVelociraptor, adhering to the designs fromJurassic Park.[73] However, the dromaeosaurPyroraptor was feathered forJurassic World Dominion, along with other changes such as stiffening the tail to account for ossified tendons and de-pronating the hands.[74]
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