Velociraptor
| Velociraptor | |
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| File:Velociraptor skelett.jpg | |
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| Genus: | Velociraptor
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| Species: | V. mongoliensis
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| Binomial name | |
| Velociraptor mongoliensis | |
Velociraptor (pronounced (U.S.) /vɛ.ˌla.sɪ.ˈræp.tər/, (U.K.) /ve.ˌlɒ.sɪ.ˈræp.tə/, 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) It had a slightly up-curved skull and a large sickle-shaped claw on the hyperextendible second toe of each foot. These dinosaurs are commonly known as raptors, a name which can also refer to other dromaeosaurids.
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 which 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) [citation needed]. Fossils have been found in Mongolia, Russia, and China.
Claws and teeth
Velociraptor had long, narrow jaws, with about 80 bladed teeth and three large, highly recurved claws on each forelimb. Unlike most theropod dinosaurs, which had three functional toes, deinonychosaurs like Velociraptor walked on only their third and forth digits. The first digit, as in other theropods, was a small dewclaw. The second digit was highly modified and held retracted off of the ground. It bore a relatively large, sickle-shaped claw typical of dromaeosaurid and troodontid dinosaurs. This distinctive claw has traditionally been depicted as a slashing weapon, used to cut and disembowel prey. However, a 2005 BBC documentary, The Truth About Killer Dinosaurs cast doubt on this hypothesis, creating an artificial Velociraptor leg and sickle claw to test the claw's function. When tested on a pork belly, the claw did not 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 'arm' of the Velociraptor is clutched in the herbivore's jaws. This suggests Velociraptor may have used its sickle claw for precision killing, to pierce its victim's jugular vein or windpipe. Some scientists have also suggested that the claw may have been used as a sort of grappling hook, helping the Velociraptor to hang onto the flanks of large prey animals while they inflicted wounds with their jaws and forelimbs. A related hypothesis suggests that the claws may have been useful in climbing trees. [citation needed]
Feathers
Whether Velociraptor was a bird or a dinosaur depends on the definition being used. Phylogenetically, all members of the clade Aves are dinosaurs. However, in traditional taxonomy and common terminology, a "bird" is not just a member of Aves but any animal with feathered wings. Under the latter definitions, 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 increasingly likely that Velociraptor and other dromaeosaurids are true birds under the phylogenetic 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 bird-like 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).
Other characteristics
Velociraptor had a stiffened tail, which was held rigidly behind the body by a series of ossified (bony) tendons. This may have granted it greater balance and turning ability than other dinosaurs [citation needed]. While Velociraptor is commonly depicted as a pack hunter, there is no evidence to support this behavior. Velociraptor was probably warm-blooded to some degree, as it probably required a significant amount of energy to hunt. Modern animals that possess feathery or furry coats, like Velociraptor likely did, 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 a weight of 20 kg (45 lb).
In popular culture
- 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, which at the time was referred to by some scientists as Velociraptor antirrhopus (notably by Gregory S. Paul, 1986). This classification, however, never came to be generally accepted. It is therefore possible that the 'raptors' in the movie are actually supposed to be Deinonychus but are referred to by the alternate taxonomy. 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. This supports the alternate taxonomy theory.
- 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 is another support for the alternate taxonomy theory, since Deinonychus fossils have been found in Montana.
- In Jurassic Park III, it is speculated that Velociraptor may have been almost as intelligent as primates. Based on fossil evidence, this is highly unlikely and it's more probable that they weren't even as smart as modern big cats.
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'.
- The NBA franchise in Toronto is the Toronto Raptors and the logo is a stylised Velociraptor.
- Atlanta, Georgia band Norma Jean's 2005 tour was called the Velociraptour, named after the Velociraptor.
- The second of two BBC documentaries in 2005 titled The Truth About Killer Dinosaurs featured Velociraptor, in an animated fight with an ankylosaur, but losing.
- Velociraptor are featured in the Walking With Dinosaurs special "The Giant Claw", shown attacking a Protoceratops, a behavior supported by fossil evidence.
- Velociraptor have the star roles in Dinosaur Planet, most notably a female trying to locate a pack.
- Velociraptor are featured in several of the Land Before Time animated films.
- In the television series Beast Wars, Dinobot had a beast form of a Velociraptor, though it suffered from the same inaccuracies as its Jurassic Park counterpart.
External links
- Images from Alain Beneteau and Mike Keesey as to what a Velociraptor may have looked like.
- Image of Velociraptor Concept by Christopher Srnka
- Image and description of Velociraptor (in german)
References
- Makovicky, Apesteguía and Agnolín (2005). "The earliest dromaeosaurid theropod from South America". Nature. 437 (7061): 1007–1011. doi:10.1038/nature03996.
- Mayr, G., B. Pohl & D.S. Peters (2005). "A well-preserved Archaeopteryx specimen with theropod features". Science. 310 (5753): 1483–1486. doi:10.1126/science.1120331.
{{cite journal}}: CS1 maint: multiple names: authors list (link) - Paul, Gregory S. (2002). Dinosaurs of the Air: The Evolution and Loss of flight in Dinosaurs and Birds. Baltimore: The Johns Hopkins University Press. ISBN 0801867630.
- Senter, P., R. Barsold, B.B. Britt and D.A. Burnham (2004). "Systematics and evolution of Dromaeosauridae (Dinosauria, Theropoda)". Bulletin of the Gunma Museum of Natural History. 8: 1–20.
{{cite journal}}: CS1 maint: multiple names: authors list (link) - Sereno, P. C. "A phylogenetic taxonomy for stem Archosauria (Tetrapoda: Reptilia)". Journal of Vertebrate Paleontology.