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}} ''Velociraptor'' (; meaning "swift seizer")〔 is a genus of dromaeosaurid theropod dinosaur that lived approximately 75 to 71 million years ago during the later 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 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. 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''. ==Description== ''Velociraptor'' was a mid-sized dromaeosaurid, with adults measuring up to long, high at the hip, and weighing up to .〔 The skull, which grew up to long, was uniquely up-curved, concave on the upper surface and convex on the lower. The jaws were lined with 26–28 widely spaced teeth on each side, each more strongly serrated on the back edge than the front. ''Velociraptor'', like other dromaeosaurids, had a large manus ('hand') with three strongly curved claws, which were similar in construction and flexibility to the wing bones of modern birds. The second digit was the longest of the three digits present, while the first was shortest. The structure of the carpal (wrist) bones prevented pronation of the wrist and forced the 'hands' to be held with the palmar surface facing inwards (medially), not downwards. The first digit of the foot, as in other theropods, was a small dewclaw. However, whereas most theropods had feet with three digits contacting the ground, dromaeosaurids like ''Velociraptor'' walked on only their third and fourth digits. The second digit, for which ''Velociraptor'' is most famous, was highly modified and held retracted off the ground. It bore a relatively large, sickle-shaped claw, typical of dromaeosaurid and troodontid dinosaurs. This enlarged claw, which could grow to over long around its outer edge,〔 was most likely a predatory device used to tear into or restrain struggling prey.〔 As in other dromaeosaurs, ''Velociraptor'' tails had long bony projections (prezygapophyses) on the upper surfaces of the vertebrae, as well as ossified tendons 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.〔 In 2007, paleontologists reported the discovery of quill knobs on a well-preserved ''Velociraptor mongoliensis'' forearm from Mongolia, confirming the presence of feathers in this species. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Velociraptor」の詳細全文を読む スポンサード リンク
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