Genus: Mantellisaurus PAUL, 2006
Etymology: In honor of the discover of Wealden iguandonts, Gidean Mantell, and Greek, sauros, 'lizard.

Species: atherfieldensis (HOOLEY, 1925) PAUL, 2006
= Iguanodon? atherfieldensis HOOLEY, 1925
Etymology:
= Iguanodon bernissartensis HOOLEY, 1917

Holotype: BMNH R5764

Locality: Cliff near Atherfield, Brightstone Bay, Isle of Wight County, England, Southern United Kingdom.

Horizon: Wessex Formation, Wealden Group.

Biostratigraphy:

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

Material: Nearly complete skull and skeleton lacking most of the tail of a juvenile.

Note: Skin impressions.

Referred material:

SERRANO, VULLO, MARUGAN-LOBON, ORTEGA, & BUSCALIONI, 2013

Locality: Las Hoyas fossil site, La Cierva Township, 20 km east of Cuenca, in the Castellan Branch of the Iberian Range, Cuenca Province, Spain.

Horizon: Calizas de La Huerguina Formation.

Biostratigraphy:

Age: Upper Hauterivian Stage, Late Neocomian subepoch-Lower Barremian Stage, Early Gallic subepoch, Early Cretaceous Epoch, Early Cretaceous.

Material:

lh-30677: Tibia, fibula, tarsals, metatarsals, phalanges.
Note: Hoot-like claws on the unguals, and possible toe pads.