Hypsilophodon
Small bipedal herbivore from the Early Cretaceous of England.
Hypsilophodon is a genus of neornithischian dinosaur from England's Early Cretaceous. It was long placed within Ornithopoda, though newer studies have challenged that. Its first fossils turned up in 1849, and the type species, *Hypsilophodon foxii*, was formally described in 1869. Numerous finds on the Isle of Wight have given a clear picture of the animal: a small, quick bipedal herbivore, about 1.5 to 2 meters long and 20 kilograms in weight. It had a pointed skull with a sharp beak, used to snip off plants much like a modern parrot.
The first specimen was uncovered in 1849 when workers dug up a block of stone from the Wessex Formation on the Isle of Wight's southwest coast. The larger half went to naturalist James Scott Bowerbank, the rest to Gideon Mantell. After Mantell died, his portion ended up at the British Museum; Bowerbank's was later acquired there too, reuniting the pieces. Richard Owen studied them in 1855 and published a short paper, concluding the remains belonged to a young *Iguanodon*, not a new type. That view held until 1867, when Thomas Henry Huxley compared the vertebrae and foot bones more closely to known *Iguanodon* and decided they had to be from a different animal. The next year, Huxley saw a fossil skull that William Fox had found in the same area, along with several other specimens. Fox thought it might be a juvenile *Iguanodon* or a new small species in that genus. Huxley noticed its unusual teeth and toothless front part of the upper jaw, which resembled but clearly differed from *Iguanodon*. He concluded this skull also belonged to a distinct animal. After losing track of the specimen for a few months, Huxley asked Fox for permission to study it in detail. Fox agreed, and Huxley began work.
Huxley first announced the new species in an 1869 lecture; the published text of that lecture, containing a sufficient description, serves as the official naming paper. He called it *Hypsilophodon foxii*, with the Fox skull as the holotype. The following year, Huxley published a full description. In the same block as the skull, a dorsal vertebra had been preserved, allowing comparison with the earlier Mantell-Bowerbank block and confirming it was the same species. Fox confirmed the block came from the same geological layer as his material, so Huxley described that specimen as well, making it the paratype. Later in 1869, Huxley classified
- field
- Paleontology
- known_for
- Early Cretaceous neornithischian dinosaur from England
- type_species
- Hypsilophodon foxii
- named_by
- Thomas Henry Huxley
- year_named
- 1869
- length
- 1.5–2 m (4.9–6.6 ft)
- weight
- 20 kg (44 lb)
Lore & Background
The first specimen of Hypsilophodon was recovered in 1849 from the Wessex Formation on the Isle of Wight. The larger half of the block was given to James Scott Bowerbank, the remainder to Gideon Mantell. Richard Owen studied both halves and in 1855 considered it a young Iguanodon. In 1867, Thomas Henry Huxley compared the vertebrae and metatarsals more closely and concluded it was a different animal. The next year, Huxley saw a fossil skull discovered by William Fox and, noting its unique dentition and edentulous premaxilla, named the new species Hypsilophodon foxii in 1869. The generic name means 'Hypsilophus-tooth', referencing an extant herbivorous lizard, not the animal's own teeth.
Reader's Guide
Hypsilophodon has been the subject of several outdated misconceptions, including that it was armoured, arboreal, or found outside the Isle of Wight; later research has shown these ideas incorrect. The debate over its distinctiveness from Iguanodon was resolved by John Whitaker Hulke's 1874 study of vertebral characters, confirming it as a distinct genus. Modern research began with Peter Malcolm Galton's 1967 thesis. A second species, Hypsilophodon wielandi, was proposed in 1979 based on a femur from South Dakota, but is now considered a dubious basal ornithopod, with H. foxii the only valid species. Most known specimens were discovered between 1849 and 1921 and are held by the Natural History Museum, representing about twenty individual animals.
Did You Know?
- The first specimen of Hypsilophodon was initially thought by Richard Owen to be a young Iguanodon.
- The generic name Hypsilophodon means 'Hypsilophus-tooth', named after an extant herbivorous lizard, not the dinosaur's own teeth.
- Outdated studies incorrectly suggested Hypsilophodon was armoured, arboreal, or lived outside the Isle of Wight.
- A second species, Hypsilophodon wielandi, was named in 1979 from a femur found in South Dakota, but is now considered dubious.
More in Extinct Archosaurs 1-24
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