English: Hylaeosaurus is a nodosaurid Ankylosaur that lived about 136 milliion years ago, in the early Cretaceous period of England. It was one of the first dinosaurs to be discovered, in 1832 by Gideon Mantell. Only limited remains have been found of Hylaeosaurus and much of its anatomy is unknown. It was about 5 m long, and estimated to have weighed around 2 t. Hylaeosaurus was an armored dinosaur covered in osteoderms, and carried at least three long spines on each shoulder.