The Dinosaurs - Mantellisaurus, an Isle of Wight Iguanodontid


an Isle of Wight Iguanodontid


Mantell’s reptile


7 m (23 feet)


Iguanodontidae Cope, 1869

Mantellisaurus atherfieldensis (Hooley, 1925)


Mantellisaurus was originally found at Atherfield Point, near Brighstone Bay. The best bet is to look in the plant debris beds, which are usually light grey, with bits of black lignite in them.

The teeth can reach up to 40 mm (1½ inches) in height, and show an expanded crown and fine denticulation. The teeth of different jaws have different wear marks. On the upper jaw there is a prominent keel in the labial (outer) surface, where as in the lower jaw the teeth have two less prominent ridges on the lingual (inner) surface. To simplify matters, this genus will be described twice, once for each species.

Mantellisaurus has a low skull, with a low angle to the articulation between the dentary and predentary. A rostrally expanded beak gives it, when viewed from above, an hourglass shaped head. Mantellisaurus had a short thumbspike and elongate, gracile metacarpals. There were 3 phalanges in the forth and fifth digits. The forearms were only 50% of the length of the hindlimbs.

The neural spines were fairly tall, with ossified tendons arranged along them, and there may have been a ridge along the back

NAISH, D. and MARTILL, D. M. 2001. Ornithopod dinosaurs. In MARTILL, D. M. and NAISH, D (eds). Dinosaurs of the Isle of Wight. The Palaeontological Association. Field Guide to Fossils 10. 60-132

NORMAN, D. B. 1986. On the Anatomy of Iguanodon atherfieldensis (Ornithischia: Ornithopoda). Bull. Inst. r. Sci. nat. Belg.: Sciences de la Terre, 56, 281-372.

PAUL, G. S. 2006. Turning the old into the new: a separate genus for the gracile iguanodont from the Wealden of England; In CARPENTER, K. (ed.), Horns and Beaks: Ceratopsian and Ornithopod Dinosaurs. Indiana University Press, Bloomington. 69-77