Mantellisaurus atherfieldensis

Mantellisaurus atherfieldensis

My wife and I have been regular visitors to the Isle of Wight for many years now and one of the most common dinosaur fossils found on the island are indeterminate ornithopod remains. Most of the fossils found eroding out of the Wealden strata on the southwest coast of the island and at Yaverland are fragmentary and isolated skeletal elements and are often identified as ornithopod, but assigning these to species or even particular genus can be difficult.

The Isle of Wight as photographed from a passing airplane by the author.

Lying off the south coast of England the island is a palaeontologists heaven with virtually all coastal exposures being fossiliferous. A chalk ridge divides the island east-west (you can the cliffs below Tennyson Down on the left and Culver Cliff on the right); exposures north of the ridge are primarily Cenozoic in age and south of the ridge they are Mesozoic, although river gravels in the southwest of the island are Quarternary in age, lie unconformably on the Wealden strata and produce bones of large mammals such as mammoth and occasional hearths of hunter-gatherers).

Almost certainly we will have somewhere in our collection a piece of Mantellisaurus altherfieldensis. Formerly attributed to Iguanodon atherfieldensis the gracile M. atherfieldensis is one of the commoner dinosaurs found on the island. In fact, the bones of iguanodonts are so common the local collectors call them 'pigs'; Dinosaur Isle in Sandown has an excellent wall-mounted specimen of Iguanodon bernissartensis (a large and more robust animal) and last time I was there the museum was preparing to display Nick Chase's iguanodont (I'm unsure of the species).

This makes it a natural choice for a sketch and I've chosen to show M. atherfieldensis as a biped, as suggested by Paul (2007).

References:

Paul, G.S. A revised taxonomy of the iguanodont dinosaur genera and species, Cretaceous Research (2007), doi: 10.1016/j.cretres.2007.04.009