''Velociraptor'' (; ) is a
genus
Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nom ...
of small
dromaeosaurid dinosaur
Dinosaurs are a diverse group of reptiles of the clade Dinosauria. They first appeared during the Triassic period, between 243 and 233.23 million years ago (mya), although the exact origin and timing of the evolution of dinosaurs is t ...
that lived in
Asia
Asia (, ) is one of the world's most notable geographical regions, which is either considered a continent in its own right or a subcontinent of Eurasia, which shares the continental landmass of Afro-Eurasia with Africa. Asia covers an are ...
during the
Late Cretaceous
The Late Cretaceous (100.5–66 Ma) is the younger of two epochs into which the Cretaceous Period is divided in the geologic time scale. Rock strata from this epoch form the Upper Cretaceous Series. The Cretaceous is named after ''creta'', ...
epoch, about 75 million to 71
million years ago
The abbreviation Myr, "million years", is a unit of a quantity of (i.e. ) years, or 31.556926 teraseconds.
Usage
Myr (million years) is in common use in fields such as Earth science and cosmology. Myr is also used with Mya (million years ago) ...
. Two species are currently recognized, although others have been assigned in the past. The
type species
In zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the species that contains the biological type specime ...
is ''V. mongoliensis'';
fossil
A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved ...
s of this species have been discovered in the
Djadochta Formation
The Djadochta Formation (sometimes Transcription (linguistics), transcribed and also known as Djadokhta, Djadokata, or Dzhadokhtskaya) is a highly fossiliferous geological formation situated in Central Asia, Gobi Desert, dating from the Late Creta ...
,
Mongolia
Mongolia; Mongolian script: , , ; lit. "Mongol Nation" or "State of Mongolia" () is a landlocked country in East Asia, bordered by Russia to the north and China to the south. It covers an area of , with a population of just 3.3 million, ...
. A second species, ''V. osmolskae'', was named in 2008 for skull material from the
Bayan Mandahu Formation
The Bayan Mandahu Formation (also known as Wulansuhai Formation or Wuliangsuhai Formation) is a geological unit of "redbeds" located near the village of Bayan Mandahu in Inner Mongolia, China Asia (Gobi Desert) and dates from the late Cretaceous ...
,
China.
Smaller than other dromaeosaurids like ''
Deinonychus
''Deinonychus'' ( ; ) is a genus of dromaeosaurid theropod dinosaur with one described species, ''Deinonychus antirrhopus''. This species, which could grow up to long, lived during the early Cretaceous Period, about 115–108 million y ...
'' and ''
Achillobator
''Achillobator'' ( ; meaning "Achilles hero") is a genus of large dromaeosaurid dinosaurs that lived in Asia during the Late Cretaceous period about 96 million to 89 million years ago in what is now the Bayan Shireh Formation. The genus is curren ...
'', ''Velociraptor'' was about long with a body mass between . It nevertheless shared many of the same
anatomical features. It was a
biped
Bipedalism is a form of terrestrial locomotion where an organism moves by means of its two rear limbs or legs. An animal or machine that usually moves in a bipedal manner is known as a biped , meaning 'two feet' (from Latin ''bis'' 'double' ...
al,
feathered
carnivore
A carnivore , or meat-eater (Latin, ''caro'', genitive ''carnis'', meaning meat or "flesh" and ''vorare'' meaning "to devour"), is an animal or plant whose food and energy requirements derive from animal tissues (mainly muscle, fat and other s ...
with a long tail and an enlarged sickle-shaped
claw
A claw is a curved, pointed appendage found at the end of a toe or finger in most amniotes (mammals, reptiles, birds). Some invertebrates such as beetles and spiders have somewhat similar fine, hooked structures at the end of the leg or tarsus ...
on each hindfoot, which is thought to have been used to tackle and restrain
prey
Predation is a biological interaction where one organism, the predator, kills and eats another organism, its prey. It is one of a family of common feeding behaviours that includes parasitism and micropredation (which usually do not kill ...
. ''Velociraptor'' can be distinguished from other dromaeosaurids by its long and low
skull
The skull is a bone protective cavity for the brain. The skull is composed of four types of bone i.e., cranial bones, facial bones, ear ossicles and hyoid bone. However two parts are more prominent: the cranium and the mandible. In humans, th ...
, with an upturned snout.
''Velociraptor'' (commonly referred to as "raptor") is one of the dinosaur genera most familiar to the general public due to its prominent role in the ''
Jurassic Park'' films. In real life, however, ''Velociraptor'' was roughly the size of a
turkey
Turkey ( tr, Türkiye ), officially the Republic of Türkiye ( tr, Türkiye Cumhuriyeti, links=no ), is a transcontinental country located mainly on the Anatolian Peninsula in Western Asia, with a small portion on the Balkan Peninsula in ...
, considerably smaller than the approximately tall and reptiles seen in the novels and films (which were based on members of the related genus ''
Deinonychus
''Deinonychus'' ( ; ) is a genus of dromaeosaurid theropod dinosaur with one described species, ''Deinonychus antirrhopus''. This species, which could grow up to long, lived during the early Cretaceous Period, about 115–108 million y ...
''). Today, ''Velociraptor'' is well known to
paleontologists
Paleontology (), also spelled palaeontology or palæontology, is the scientific study of life that existed prior to, and sometimes including, the start of the Holocene epoch (roughly 11,700 years before present). It includes the study of foss ...
, 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''.
History of discovery
During an
American Museum of Natural History expedition to the
Flaming Cliffs
The Flaming Cliffs site (also known as Bayanzag ( zh, 巴彥扎格), Bain-Dzak or Bayn Dzak) ( mn, Баянзаг ''rich in saxaul''), with the alternative Mongolian name of mn, Улаан Эрэг (''red cliffs''), is a region of the Gobi Deser ...
(Bayn Dzak or Bayanzag) of the
Djadochta Formation
The Djadochta Formation (sometimes Transcription (linguistics), transcribed and also known as Djadokhta, Djadokata, or Dzhadokhtskaya) is a highly fossiliferous geological formation situated in Central Asia, Gobi Desert, dating from the Late Creta ...
,
Gobi Desert, on 11 August 1923, Peter Kaisen discovered the first ''Velociraptor'' fossil known to science—a crushed but complete skull, associated with one of the raptorial second toe claws (
AMNH
The American Museum of Natural History (abbreviated as AMNH) is a natural history museum on the Upper West Side of Manhattan in New York City. In Theodore Roosevelt Park, across the street from Central Park, the museum complex comprises 26 i ...
6515). In 1924, museum president
Henry Fairfield Osborn
Henry Fairfield Osborn, Sr. (August 8, 1857 – November 6, 1935) was an American paleontologist, geologist and eugenics advocate. He was the president of the American Museum of Natural History for 25 years and a cofounder of the American Euge ...
designated the skull and claw (which he assumed to come from the hand) as the
type specimen
In biology, a type is a particular specimen (or in some cases a group of specimens) of an organism to which the scientific name of that organism is formally attached. In other words, a type is an example that serves to anchor or centralizes th ...
of his new genus, ''Velociraptor''. This name is derived from the
Latin
Latin (, or , ) is a classical language belonging to the Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through the power of the ...
words ''velox'' ('swift') and ''raptor'' ('robber' or 'plunderer') and refers to the animal's
cursorial nature and carnivorous diet. Osborn named the type species ''V. mongoliensis'' after its country of origin.
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 named ''
Oviraptor
''Oviraptor'' (; ) is a genus of oviraptorid dinosaur that lived in Asia during the Late Cretaceous period. The first remains were collected from the Djadokhta Formation of Mongolia in 1923 during a paleontological expedition led by Roy Chapma ...
''),
eventually changed into ''V. mongoliensis'' during its formal description.
[
While North American teams were shut out of communist Mongolia during the Cold War, expeditions by ]Soviet
The Soviet Union,. officially the Union of Soviet Socialist Republics. (USSR),. was a transcontinental country that spanned much of Eurasia from 1922 to 1991. A flagship communist state, it was nominally a federal union of fifteen nation ...
and Polish scientists, in collaboration with Mongolian colleagues, recovered several more specimens of ''Velociraptor''. 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 a ''Velociraptor'' in battle against a '' Protoceratops''. It is considered a national treasure of Mongolia, and in 2000 it was loaned to the American Museum of Natural History in New York City
New York, often called New York City or NYC, is the most populous city in the United States. With a 2020 population of 8,804,190 distributed over , New York City is also the most densely populated major city in the Un ...
for a temporary exhibition.
Between 1988 and 1990, a joint Chinese-Canadian
Canadians (french: Canadiens) are people identified with the country of Canada. This connection may be residential, legal, historical or cultural. For most Canadians, many (or all) of these connections exist and are collectively the source of ...
team discovered ''Velociraptor'' remains in northern China. 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 the Mongolian Academy of Sciences, turned up several well-preserved skeletons. 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 the Washington Irving
Washington Irving (April 3, 1783 – November 28, 1859) was an American short-story writer, essayist, biographer, historian, and diplomat of the early 19th century. He is best known for his short stories "Rip Van Winkle" (1819) and " The Legen ...
character Ichabod Crane).[Novacek, Michael J. (1996). ''Dinosaurs of the Flaming Cliffs''. New York: Anchor Books. .] While Norell and Makovicky provisionally considered it a specimen of ''Velociraptor mongoliensis'',[ it was named as a new species '' Shri devi'' in 2021.]
Additional species
Maxilla
The maxilla (plural: ''maxillae'' ) in vertebrates is the upper fixed (not fixed in Neopterygii) bone of the jaw formed from the fusion of two maxillary bones. In humans, the upper jaw includes the hard palate in the front of the mouth. T ...
e and a lacrimal (the main tooth-bearing bones of the upper jaw, and the bone that forms the anterior margin of the eye socket, respectively) recovered from the Bayan Mandahu Formation
The Bayan Mandahu Formation (also known as Wulansuhai Formation or Wuliangsuhai Formation) is a geological unit of "redbeds" located near the village of Bayan Mandahu in Inner Mongolia, China Asia (Gobi Desert) and dates from the late Cretaceous ...
in 1999 by the Sino-Belgian Dinosaur Expeditions were found to pertain to ''Velociraptor'', but not to the type species ''V. mongoliensis''. Pascal Godefroit Pascal Godefroit is a Belgian paleontologist. He discovered dinosaurs like '' Olorotitan'' in 2003. Godefroit is the director of earth and life sciences
This list of life sciences comprises the branches of science that involve the scientific st ...
and colleagues named these bones ''V. osmolskae'' (for Polish paleontologist Halszka Osmólska) in 2008. However, the 2013 study noted that while "the elongate shape of the maxilla in ''V. osmolskae'' is similar to that of ''V. mongoliensis''," phylogenetic analysis found it to be closer to '' Linheraptor'', making the genus paraphyletic; thus, ''V. osmolskae'' might not actually belong to the genus ''Velociraptor'' and requires reassessment.
Paleontologists Mark A. Norell and Peter J. Makovicky in 1997 described new and abundantly preserved specimens of ''V. 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.[ In 1999 Norell and Makovicky provided more insights into the anatomy of ''Velociraptor'' with additional specimens. Among these, MPC-D 100/982 was partially described and figured, and referred to ''V. 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 other ''Velociraptor'' specimens. This relatively well-preserved specimen including the skull was discovered and collected in 1995 at the Bayn Dzak locality (more especifically at the "Volcano" sub-locality).][ Martin Kundrát in a 2004 abstract compared the neurocranium of MPC-D 100/982 to another ''Velociraptor'' 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.
Mark J. Powers in his 2020 master thesis fully described MPC-D 100/982, which he concluded to represent a new and third species of ''Velociraptor''. This species, which he named ''"V. vadarostrum"'', was stated to mainly differ from other ''Velociraptor'' species in having a shallow maxilla morphology. Powers and colleagues also in 2020 used morphometric analyses to compare several dromaeosaurid maxillae, and found the maxilla of MPC-D 100/982 to strongly differ from specimens referred to ''Velociraptor''. They indicated that this specimen, based on these results, represents a different species. In 2021 Powers with team used Principal Component Analysis to separate dromaeosaurid maxillae, most notably finding that MPC-D 100/982 falls outside the instraspecific variability of ''V. mongoliensis'', arguing for a distinct species. They considered that both ''V. mongoliensis'' and this new species were ecologically separated based on their skull anatomy. The team in another 2021 abstract reinforced again the species-level separation, noting that additional differences can be found in the hindlimbs.
]
Description
''Velociraptor'' was a small to medium-sized dromaeosaurid, with adults measuring between long, approximately high at the hips,[ and weighing about .
Prominent quill knobs—attachment site of "]wing
A wing is a type of fin that produces lift while moving through air or some other fluid. Accordingly, wings have streamlined cross-sections that are subject to aerodynamic forces and act as airfoils. A wing's aerodynamic efficiency is e ...
" feathers and direct indicator of a feather covering—have been reported from the ulna
The ulna (''pl''. ulnae or ulnas) is a long bone found in the forearm that stretches from the elbow to the smallest finger, and when in anatomical position, is found on the medial side of the forearm. That is, the ulna is on the same side of t ...
of a single ''Velociraptor'' specimen (IGM 100/981), which represents an animal of estimated long and 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 large secondaries ("wing" feathers stemming from the forearm). However, the specimen number has been corrected to IGM 100/3503 and its referral to ''Velociraptor'' may require reevaluation, pending further study.[ Nevertheless, there is strong phylogenetic evidence from other dromaeosaurid relatives that indicates the presence of feathers in ''Velociraptor'', including dromaeosaurids such as '' Microraptor'' or '']Zhenyuanlong
''Zhenyuanlong'' (meaning ''"Zhenyuan's dragon"'', from Chinese Pinyin 龙/ 龍 lóng ''"dragon"'') is a genus of dromaeosaurid dinosaur from the Yixian Formation of Liaoning, China. It lived during the Aptian age of the early Cretaceous perio ...
''.
Skull
The skull of ''Velociraptor'' was rather elongated and grew up to 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. The 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. The 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 several alveoli (tooth
A tooth ( : teeth) is a hard, calcified structure found in the jaws (or mouths) of many vertebrates and used to break down food. Some animals, particularly carnivores and omnivores, also use teeth to help with capturing or wounding prey, t ...
sockets) on their bottom surfaces. Above the maxilla and making contact with the premaxilla, there was the 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.
The back or anterior region of the skull was built by the frontal, lacrimal, postorbital, jugal, parietal, quadrate, and quadratojugal bones. The was large element, having a vaguely rectangular shape when seen from above. On its posterior end, this bone was in contact with the , and such elements were the main bodies of the skull roof. The was a T-shaped bone and its main body was thin and delicated. Its lower end meet the (often called cheek bone), which was a large, sub-triangular-shaped element. Its lower border was notably straight/horizontal. The 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 the , was developed. While the upper end of the quadratojugal joined the , an irregularly-shaped element, its inner side meet the . The latter was of great importance for the articulation with the lower jaw. The posteriormost bone was the and its projection the occipital condyle
The occipital condyles are undersurface protuberances of the occipital bone in vertebrates, which function in articulation with the superior facets of the atlas vertebra.
The condyles are oval or reniform (kidney-shaped) in shape, and their anteri ...
: a rounded and bulbous protuberance that meet the first vertebra of the neck.[
The lower jaw of ''Velociraptor'' comprised mainly the dentary, splenial, angular, surangular, and articular bones. The was a very long, weakly curved, and narrow element that developed several alveoli on its top surface. On its posterior end, it meet the . It had a small hole near its posterior end, called surangular foramen or fenestra. Both bones were the largest elements of the lower jaw of ''Velociraptor'', contributing to virtually its entire length. Below them were the smaller and , closely articulated to each other. The , 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.][
The teeth of ''Velociraptor'' were fairly homodont (equal in shape) and had several denticles (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.][
]
Postcranial skeleton
The arm of ''Velociraptor'' was formed by the humerus (upper arm bone), radius
In classical geometry, a radius ( : radii) of a circle or sphere is any of the line segments from its center to its perimeter, and in more modern usage, it is also their length. The name comes from the latin ''radius'', meaning ray but also the ...
and ulna
The ulna (''pl''. ulnae or ulnas) is a long bone found in the forearm that stretches from the elbow to the smallest finger, and when in anatomical position, is found on the medial side of the forearm. That is, the ulna is on the same side of t ...
(forearm bones), and manus (hand). ''Velociraptor'', like other dromaeosaurids, had a large manus with three elongated digits (fingers), which ended up in strongly curved unguals (claw bones) that were similar in construction and flexibility to the wing bones of modern bird
Birds are a group of warm-blooded vertebrates constituting the class Aves (), characterised by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a strong yet lightweig ...
s. The second digit was the longest of the three digits present, while the first was shortest. The structure of the carpal
The carpal bones are the eight small bones that make up the wrist (or carpus) that connects the hand to the forearm. The term "carpus" is derived from the Latin carpus and the Greek καρπός (karpós), meaning "wrist". In human anatomy, the ...
(wrist) bones prevented pronation of the wrist and forced the manus to be held with the palmar surface facing inward ( medially), not downward. The pes (foot) anatomy of ''Velociraptor'' 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 small dewclaw
A dewclaw is a digit – vestigial in some animals – on the foot of many mammals, birds, and reptiles (including some extinct orders, like certain theropods). It commonly grows higher on the leg than the rest of the foot, such that in digit ...
. The second digit, for which ''Velociraptor'' is most famous, was highly modified and held retracted off the ground, which caused ''Velociraptor'' and other dromaeosaurids to walk on only their third and fourth digits. It bore a relatively large, sickle-shaped claw, typical of dromaeosaurid and troodontid
Troodontidae is a clade of bird-like theropod dinosaurs. During most of the 20th century, troodontid fossils were few and incomplete and they have therefore been allied, at various times, with many dinosaurian lineages. More recent fossil disco ...
dinosaurs. This enlarged claw, which could grow to over long around its outer edge, was most likely a predatory device used to restrain struggling prey.[
As in other dromaeosaurs, ''Velociraptor'' tails had prezygapophyses (long bony projections) on the upper surfaces of the ]vertebra
The spinal column, a defining synapomorphy shared by nearly all vertebrates, Hagfish are believed to have secondarily lost their spinal column is a moderately flexible series of vertebrae (singular vertebra), each constituting a characteristi ...
e, as well as ossified
Ossification (also called osteogenesis or bone mineralization) in bone remodeling is the process of laying down new bone material by cells named osteoblasts. It is synonymous with bone tissue formation. There are two processes resulting in t ...
tendon
A tendon or sinew is a tough, high-tensile-strength band of dense fibrous connective tissue that connects muscle to bone. It is able to transmit the mechanical forces of muscle contraction to the skeletal system without sacrificing its ability ...
s 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 an ''S''-shape, suggesting that there was considerably more horizontal flexibility than once thought.[
]
Classification
''Velociraptor'' is a member of the group Eudromaeosauria
Eudromaeosauria ("true dromaeosaurs") is a subgroup of terrestrial dromaeosaurid theropod dinosaurs. They were relatively small to medium-sized, feathered hypercarnivores (with diets consisting almost entirely of other terrestrial vertebrates) ...
, a derived sub-group of the larger family Dromaeosauridae. It is often placed within its own subfamily, Velociraptorinae
Velociraptorinae is a subfamily of the theropod group Dromaeosauridae. The earliest velociraptorines are probably ''Nuthetes'' from the United Kingdom, and possibly '' Deinonychus'' from North America. However, several indeterminate velociraptor ...
. In phylogenetic taxonomy, Velociraptorinae is usually defined as "all dromaeosaurs more closely related to ''Velociraptor'' than to '' Dromaeosaurus''." However, dromaeosaurid classification is highly variable. Originally, the subfamily Velociraptorinae was erected solely to contain ''Velociraptor''.[ Other analyses have often included other genera, usually ''Deinonychus'' and '' Saurornitholestes'',] and more recently ''Tsaagan''. 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 the Dromaeosaurinae
Dromaeosaurinae is a subfamily of the theropod group Dromaeosauridae. The earliest dromaeosaurine is ''Utahraptor'', dating back to the Early Cretaceous period in North America, however, some isolated teeth seems to represent an indeterminate spe ...
.
When first described in 1924, ''Velociraptor'' was placed in the family Megalosauridae
Megalosauridae is a monophyletic family of carnivorous theropod dinosaurs within the group Megalosauroidea. Appearing in the Middle Jurassic, megalosaurids were among the first major radiation of large theropod dinosaurs. They were a relatively ...
, as was the case with most carnivorous dinosaurs at the time (Megalosauridae, like ''Megalosaurus
''Megalosaurus'' (meaning "great lizard", from Greek , ', meaning 'big', 'tall' or 'great' and , ', meaning 'lizard') is an extinct genus of large carnivorous theropod dinosaurs of the Middle Jurassic period (Bathonian stage, 166 million years ...
'', functioned as a sort of 'wastebin' taxon, where many unrelated species were grouped together). As dinosaur discoveries multiplied, ''Velociraptor'' was later recognized as a dromaeosaurid. All dromaeosaurids have also been referred to the family Archaeopterygidae
Archaeopterygidae is a group of maniraptoran dinosaurs, known from the latest Jurassic and earliest Cretaceous of Europe. In most current classifications, it contains only the genera ''Archaeopteryx'' and ''Wellnhoferia''. As its name suggests, ...
by at least one author (which would, in effect, make ''Velociraptor'' a flightless bird). In the past, other dromaeosaurid species, including ''Deinonychus antirrhopus'' and ''Saurornitholestes langstoni'', have sometimes been classified in the genus ''Velociraptor''. Since ''Velociraptor'' was the first to be named, these species were renamed ''Velociraptor antirrhopus'' and ''V. langstoni''. As of 2008, the only currently recognized species of ''Velociraptor'' are ''V. mongoliensis'' and ''V. osmolskae''.[ However, several studies have found "''V.''" ''osmolskae'' to be distantly related to ''V. mongoliensis''.][ Material was copied from this source, which is available under ]
Creative Commons Attribution 4.0 International License
Below are the results for the Eudromaeosauria phylogeny
A phylogenetic tree (also phylogeny or evolutionary tree Felsenstein J. (2004). ''Inferring Phylogenies'' Sinauer Associates: Sunderland, MA.) is a branching diagram or a tree showing the evolutionary relationships among various biological spe ...
based on the phylogenetic analysis
In biology, phylogenetics (; from Greek φυλή/ φῦλον [] "tribe, clan, race", and wikt:γενετικός, γενετικός [] "origin, source, birth") is the study of the evolutionary history and relationships among or within groups o ...
conducted by James G. Napoli and team in 2021 during the description of '' Kuru'', showing the position of ''Velociraptor'':
Paleobiology
Feathers
In 2007 Alan H. Turner and colleagues reported the presence of six quill knobs in the ulna of a referred ''Velociraptor'' specimen (IGM 100/981) from the Ukhaa Tolgod locality of the Djadochta Formation
The Djadochta Formation (sometimes Transcription (linguistics), transcribed and also known as Djadokhta, Djadokata, or Dzhadokhtskaya) is a highly fossiliferous geological formation situated in Central Asia, Gobi Desert, dating from the Late Creta ...
. Turner and colleagues interpreted the presence of feathers on ''Velociraptor'' as evidence against the idea that the larger, flightless maniraptora
Maniraptora is a clade of coelurosaurian dinosaurs which includes the birds and the non-avian dinosaurs that were more closely related to them than to ''Ornithomimus velox''. It contains the major subgroups Avialae, Deinonychosauria, Oviraptoros ...
ns 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 in ''Velociraptor'' (presumed to have been flightless due to its relatively large size and short forelimbs) is evidence that the ancestors of dromaeosaurids could fly, making ''Velociraptor'' and other large members of this family secondarily flightless, though it is possible the large wing feathers inferred in the ancestors of ''Velociraptor'' had a purpose other than flight. The feathers of the flightless ''Velociraptor'' may have been used for display, for covering their nests while brooding, or for added speed and thrust when running up inclined slopes.[ Because of the presence of another dromaeosaurid in Ukhaa Tolgod, '' Tsaagan'', Napoli and team have noted that the referral of this specimen to ''Velociraptor'' is currently subject to rexamination.][
]
Senses
Examinations of the endocranium of ''Velociraptor'' 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 suggesting ''Velociraptor'' 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.
Feeding
In 2020, Powers and colleagues re-examined the maxillae of several eudromaeosaur 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 the premaxilla
The premaxilla (or praemaxilla) is one of a pair of small cranial bones at the very tip of the upper jaw of many animals, usually, but not always, bearing teeth. In humans, they are fused with the maxilla. The "premaxilla" of therian mammal has ...
and overall snout. For instance, most Asian species have elongated snouts based on the maxilla (namely velociraptorines), indicating a selective feeding in ''Velociraptor'' 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 dromaeosurine ''Achillobator'' is a unique exception to Asian taxa with its deep maxilla.
Predatory behavior
The " Fighting Dinosaurs" specimen, found in 1971, preserves a ''Velociraptor mongoliensis'' and ''Protoceratops andrewsi
''Protoceratops'' (; ) is a genus of small protoceratopsid dinosaurs that lived in Asia during the Late Cretaceous, around 75 to 71 million years ago. The genus ''Protoceratops'' includes two species: ''P. andrewsi'' and the larger ''P. hellenik ...
'' in combat and provides direct evidence of predatory behavior. When originally reported, it was hypothesized that the two animals drowned.[ 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 a ]sandstorm
A dust storm, also called a sandstorm, is a meteorological phenomenon common in arid and semi-arid regions. Dust storms arise when a gust front or other strong wind blows loose sand and dirt from a dry surface. Fine particles are transpo ...
. Burial must have been extremely fast, judging from the lifelike poses in which the animals were preserved. Parts of the ''Protoceratops'' are missing, which has been seen as evidence of scavenging
Scavengers are animals that consume dead organisms that have died from causes other than predation or have been killed by other predators. While scavenging generally refers to carnivores feeding on carrion, it is also a herbivorous feeding ...
by other animals. Comparisons between the scleral rings of ''Velociraptor'', ''Protoceratops'', and modern birds and reptiles indicates that ''Velociraptor'' may have been nocturnal, while ''Protoceratops'' may have been cathemeral
Cathemerality, sometimes called metaturnality, is an organismal activity pattern of irregular intervals during the day or night in which food is acquired, socializing with other organisms occurs, and any other activities necessary for livelihood ar ...
, active throughout the day during short intervals, suggesting that the fight may have occurred at twilight or during low-light conditions.
The distinctive claw, on the second digit of dromaeosaurids, has traditionally been depicted as a slashing weapon; its assumed use being to cut and disembowel
Disembowelment or evisceration is the removal of some or all of the organs of the gastrointestinal tract (the bowels, or viscera), usually through a horizontal incision made across the abdominal area. Disembowelment may result from an accident ...
prey. In the "Fighting Dinosaurs" specimen, the ''Velociraptor'' lies underneath, with one of its sickle claws apparently embedded in the throat of its prey, while the beak of ''Protoceratops'' is clamped down upon the right forelimb of its attacker. This suggests ''Velociraptor'' may have used its sickle claw to pierce vital organs of the throat, such as the jugular vein
The jugular veins are veins that take deoxygenated blood from the head back to the heart via the superior vena cava. The internal jugular vein descends next to the internal carotid artery and continues posteriorly to the sternocleidomastoid mu ...
, carotid artery, or trachea
The trachea, also known as the windpipe, is a cartilaginous tube that connects the larynx to the bronchi of the lungs, allowing the passage of air, and so is present in almost all air- breathing animals with lungs. The trachea extends from the ...
(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 of skin
Skin is the layer of usually soft, flexible outer tissue covering the body of a vertebrate animal, with three main functions: protection, regulation, and sensation.
Other animal coverings, such as the arthropod exoskeleton, have different de ...
and muscle of large prey species would have been difficult to slash without a specialized cutting surface.[ The slashing ]hypothesis
A hypothesis (plural hypotheses) is a proposed explanation for a phenomenon. For a hypothesis to be a scientific hypothesis, the scientific method requires that one can test it. Scientists generally base scientific hypotheses on previous obse ...
was tested during a 2005 BBC #REDIRECT BBC #REDIRECT BBC
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...
''. The producers of the program created an artificial ''Velociraptor'' leg with a sickle claw and used a
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.
Remains of ''
'', a closely related dromaeosaurid, have commonly been found in aggregations of several individuals. ''Deinonychus'' has also been found in association with the large ornithopod ''
'', which has been cited as evidence of cooperative (pack) hunting.
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.
Although many isolated fossils of ''Velociraptor'' have been found in Mongolia, none were closely associated with other individuals.