What is Hypsilophodon?
{{Taxobox | color = lightblue | name = ''Hypsilophodon'' | fossil_range = [[Lower Cretaceous]], 130&ndash;125 mya | image = Hypsilophodon Melb Museum email.jpg | image_caption = ''Hypsilophodon'' skeleton. | regnum = [[Animal]]ia | phylum = [[Chordate|Chordata]] | classis = [[Sauropsida]] | superordo = [[Dinosaur]]ia | ordo = [[Ornithischia]] | subordo = [[Ornithopoda]] | familia = '''Hypsilophodontidae''' | genus = '''''Hypsilophodon''''' | binomial = ''Hypsilophodon foxii'' | binomial_authority = [[Thomas Henry Huxley|Huxley]], 1869 }} [[File:Hypsilophodon foxi.JPG|thumb|right|250px|Specimens NHM R5829 and R5830 at Natural History Museum, London]] '''''Hypsilophodon''''' was a small, fast-running, [[plant]]-[[eating]] [[dinosaur]]. It lived 125 [[million]] [[year]]s ago, was 2.3 metres long (7/8 feet), including tail, and weighed about the same as a man. It was originally thought to be a young ''[[Iguanodon]]'' which could climb trees. Later it was realised to be a different [[species]], and to be a running dinosaur, not adapted for climbing. == Palaeobiology == Like most small dinosaurs, ''Hypsilophodon'' was [[bipedal]] and ran on two legs. Its entire body was built for running; a light-weight, low, [[aerodynamic]] posture, long legs and stiff tail for balance. All this would have allowed it to travel remarkably fast for its size. ''Hypsilophodon'' fed on low-growing vegetation, most likely preferring young shoots and roots in the manner of modern [[deer]]. The structure of its skull, with the teeth set far back into the jaw, strongly suggests that it had cheeks, an advanced feature that would have facilitated the chewing of food. There were twenty-eight to thirty ridged teeth in the animal's jaw which, due to their alternate arrangement, appear to have been self-sharpening. As in almost all dinosaurs and certainly all the [[ornithischia]]ns, the teeth were continuously replaced. The level of parental care in this dinosaur has not been defined, although a neatly-arranged nest has been found, suggesting