Hypsilophodon

Hypsilophodon (; meaning "Hypsilophus-tooth") is a neornithischian dinosaur genus from the Early Cretaceous period of England. It has traditionally been considered an early member of the group Ornithopoda, but recent research has put this into question.

The first remains of Hypsilophodon were found in 1849; the type species, Hypsilophodon foxii, was named in 1869. Abundant fossil discoveries were made on the Isle of Wight, giving a good impression of the build of the species. It was a small, agile bipedal herbivore, measuring 1.5–2 m (4.9–6.6 ft) long and weighing 20 kg (44 lb). It had a pointed head equipped with a sharp beak used to bite off plant material, much like modern-day parrots.

Some outdated studies have given rise to a number of misconceptions about Hypsilophodon, including that it was an armoured, arboreal animal, and that it could be found in areas outside of the Isle of Wight. However, research from the following years has shown these ideas to be incorrect.

Discovery and history

First specimens and the debate of distinctiveness

The first specimen of Hypsilophodon was recovered in 1849, when workers dug up the soon-called Mantell-Bowerbank block from an outcrop of the Wessex Formation, part of the Wealden Group, about one hundred yards west of Cowleaze Chine, on the south-west coast of Isle of Wight. The larger half of the block (including seventeen vertebrae, parts of ribs and a coracoid, some of the pelvis, and assorted hindleg remains) was given to naturalist James Scott Bowerbank, and the remainder (including eleven caudal vertebrae and most of the rest of hindlegs) to Gideon Mantell.