Velociraptor

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{{Taxobox | image=Velociraptor_skelett.jpg | image_width=250px | color = pink | name = Velociraptor | status = Conservation status: Fossil | regnum = Animalia | phylum = Chordata | classis = Sauropsida | superordo = Dinosauria | ordo = Saurischia | subordo = Theropoda | unranked_familia = Deinonychosauria | familia = Dromaeosauridae | genus = Velociraptor | binomial = Velociraptor mongoliensis | binomial_authority = Osborn, 1924 }}

Velociraptor (pronounced (U.S.) Template:IPA, (U.K.) Template:IPA, or approximately veh-LOSS-ih-RAP-tor) meaning "swift thief", referring to its speed and grasping hands (Latin velocis = swift + raptor = thief) was a small, agile, and slender theropod dinosaur species from the Late Cretaceous Period (Campanian age), with a slightly up-curved skull and large sickle-shaped claws on the hyperextendible second toe of each foot. They are commonly known as raptors, a name which can also refer to other dromaeosaurids.

Contents

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Claws and teeth

Velociraptor had strong jaws with rows of about 80 bladed teeth. These, in combination with large claws on their forelimbs and sickle-shaped talons on the second toe gave them some impressive weaponry.

In 2005, a BBC documentary, The Truth About Killer Dinosaurs, created an artificial Velociraptor leg and sickle claw to demonstrate the claw's power - when tested on a pork belly, the claw failed to fully penetrate it, a finding which does not support the popular notion that Velociraptor used the claw to disembowel prey.

Evidence as to how the claw was actually used is provided by one of the more spectacular specimens of Velociraptor, found in the Gobi desert in 1971. It is a complete, articulated skeleton clutching the skeleton of a Protoceratops. The penetrating toe claw is near to where the Protoceratops' jugular vein would have been, and the Velociraptors arm is clutched in the herbivore's jaws. This suggests Velociraptor used its sickle claw for precision killing, to pierce its victim's jugular vein or windpipe.

Velociraptor was first found and described by paleontologist H. F. Osborn in Mongolia in 1924. About a dozen Velociraptor fossils have been found, including one who died in a battle to the death with Protoceratops and two hatchling Velociraptor skulls that were found near an oviraptorid nest in Mongolia (they may have been a meal). Fossils have been found in Mongolia, Russia, and China.

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Feathers

Whether Velociraptor was a bird or a dinosaur depends on the definition being used. Technically all members of the clade Aves are dinosaurs, however, in common usage a "bird" is not just a member of Aves, but any animal with feathered wings. Under the latter definition, Velociraptor and all maniraptor "dinosaurs" are actually birds, since they evolved from feather-bearing animals (Makovicky et al., 2005), (Senter et al., 2004). Recently, fossils of dromaeosaurids more primitive than Velociraptor have been found in China with feathers covering their bodies, and fully developed feathered wings. In light of this, it is most likely that Velociraptor bore feathers too (although fossil evidence has not yet confirmed this), since even flightless birds today retain most of their feathers, and Velociraptor would be no exception (Paul, 2002). It is becoming very likely that Velociraptor and other dromaeosaurids are true birds under the technical definition, as well as the common usage of the word (Paul, 2002). The "primitive" dromaeosaurs, such as Microraptor and Rahonavis, have turned out to be more birdlike than the advanced forms like Velociraptor (some could even fly, making it likely that Velociraptor was secondarily flightless, like an ostrich, having evolved from flying ancestors) (Paul, 2002), (Makovicky et al., 2005). The discovery in 2005 of the Thermopolis specimen of Archaeopteryx, which preserves a dromaeosaur-like hyperextendible second toe, may mean that Archaeopteryx itself is more primitive than Velociraptor (Mayr et al., 2005). If this turns out to be the case, all dromaeosaurs must be considered true birds and members of the class Aves (as defined in Sereno, 2005).

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Other characteristics

Velociraptor had a stiffened tail, which was always held straight behind the body. This granted it superior balance and turning ability. Like its larger American relative Deinonychus, Velociraptor may have hunted in packs to make up for its prey's size advantage, though there is no evidence for this. Velociraptor was probably warm-blooded to some degree, as it would need great quantities of energy to hunt, and animals that possess feathery or furry coats, like Velociraptor, tend to be warm blooded since these coverings function as insulation.

Velociraptor had a skull length of 249 mm (9.80 in), a total length of 1.8 m (6 ft), a total height of 0.8 m (2.5 feet), a hip height of 0.5 m (1 ft 8 in), and weighs 20 kg (45 lb).

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In popular culture

Image:Velociraptor.jpg

  • Velociraptor is well-known in its role as a vicious and cunning killer from the novel and movie Jurassic Park. The "raptors" portrayed there were modelled after a larger relative, Deinonychus. While the movie was in production, the discovery of Utahraptor confirmed that even larger dromaeosaurids did in fact exist. The raptors depicted in the Jurassic Park films are scientifically inaccurate in numerous ways. Among the inaccuracies:
    • Their size does not correspond closely to Velociraptor and is more like that of Deinonychus.
    • They were covered in scales. (As of this date no evidence of body scales has been reported for any maniraptoran dinosaur. It is more likely that they were covered in feathers, though evidence for feathers does not yet exist for all species. However, the film was created in the early 1990s, when this was not known for certain.)
    • Their arms/hands did not closely resemble those of real dromaeosaurs, and their tails were too short and too flexible.
    • The fossil in the movie was in Montana, instead of the Gobi desert. This inaccuracy can actually be attributed to the fact that, at the time Michael Crichton began his work on the book Jurassic Park, the species Deinonychus was referred to as Velociraptor antirrhopus by some scientists (notably Gregory S. Paul, 1986). Later, around the time of the movie production, this name was changed back to Deinonychus. It is therefore possible that the 'raptors' in the movie are actually supposed to be Deinonychus except are still referred to by their older taxonomy.

Megaraptor, once thought to be an even larger raptor with a sickle-claw large enough to match the curved shape of a football, is now known to be a Carnosaur, and the sickle-claw was discovered to be a claw from its hand.

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Links to images

Images from Alain Beneteau and Mike Keesey as to what a Velociraptor may have looked like.

Image of Velociraptor Concept by Christopher Srnka

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References

  • {{cite journal 
| author = Makovicky, Apesteguía and Agnolín
| year = 2005
| title = The earliest dromaeosaurid theropod from South America
| journal = Nature
| volume = 437
| pages = 1007-1011
| id = Template:Doi
| issue = 7061
}}
  • {{cite journal 
| author = Mayr, G., B. Pohl & D.S. Peters
| year = 2005
| title = A well-preserved Archaeopteryx specimen with theropod features
| journal = Science
| volume = 310
| pages = 1483-1486
| id = Template:Doi
| issue = 5753
}}
  • {{cite book 
| author = Paul, Gregory S.
| year = 2002
| title = Dinosaurs of the Air: The Evolution and Loss of flight in Dinosaurs and Birds
| location =  Baltimore
| publisher =  The Johns Hopkins University Press
| ISBN = 0801867630
}}
  • {{cite journal 
| author = Senter, P., R. Barsold, B.B. Britt and D.A. Burnham
| year = 2004
| title = Systematics and evolution of Dromaeosauridae (Dinosauria, Theropoda)
| journal = Bulletin of the Gunma Museum of Natural History
| volume = 8
| pages =  1-20
}}
  • {{cite journal 
| author = Sereno, P. C.
| year = 
| title = A phylogenetic taxonomy for stem Archosauria (Tetrapoda: Reptilia).
| journal = Journal of Vertebrate Paleontology
| volume = 
| pages =  
}}ast:Velociraptor

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