Genus: Hylaeosaurus MANTELL, 1833
Etymology: Greek, hylaios, “belonging to the forest (Wealden) and Greek, sauros, “lizard”: “Wealden lizard”.

Species: armatus MANTELL, 1833

Holotype: BMNH 3775

Locality: An imprecisely located quarry of Tilgate Forest area, near Cuckfield, West Sussex County, England, Southern United Kingdom.

Horizon: Lower Wealden Formation.


Age: Late Valanginian Stage, Middle Neocomian Subepoch-Early Barremian Stage, Lower Gallic Subepoch, Early Cretaceous Epoch, Early Cretaceous.

Material: Base of skull, 10 anterior cervical vertebrae, 2 coracoids, 2 distal parts of scapula, fragmentary ?humerus, loose vertebrae, several ribs and armor elements consists of cervical and shoulder regions including spines, spikes, scutes and small ossicles of an immature specimen..