Discovery and naming of the holotype The
holotype fossil, NHMUK PV R5764, was originally discovered by
Reginald Walter Hooley in 1914 in the upper
Vectis Formation of southern England and reported upon in 1917. He posthumously named it
Iguanodon atherfieldensis in 1925.
Atherfield is the name of a village on the southwest shore of the
Isle of Wight where the fossil was found. He was led to identify it as an
Iguanodon based on its distinctive teeth. The Maidstone slab was utilized in the first skeletal reconstructions and artistic renderings of
Iguanodon, but due to its incompleteness, Mantell made some mistakes, the most famous of which was the placement of what he thought was a
horn on the nose. Shortly after the discovery, tension began to build between Mantell and
Richard Owen, an ambitious scientist with much better funding and society connections in the turbulent worlds of
Reform Act–era British politics and science. Owen, at the time a firm
creationist, opposed the early versions of
evolutionary science ("
transmutationism") then being debated and used what he would soon coin as dinosaurs as a weapon in this conflict. With the paper describing Dinosauria, he scaled down dinosaurs from lengths of over 61 metres (200 ft), determined that they were not simply giant lizards, and put forward that they were advanced and mammal-like, characteristics given to them by
God; according to the understanding of the time, they could not have been "transmuted" from reptiles to mammal-like creatures. In 1849, a few years before his death in 1852, Mantell realised that the genus today known as
Mantellodon was not a heavy,
pachyderm-like animal, as Owen was putting forward, but had slender forelimbs; however, his passing left him unable to participate in the creation of the
Crystal Palace dinosaur sculptures, and so Owen's vision of the dinosaurs became that seen by the public for decades. The discovery of much better specimens of
Iguanodon bernissartensis in later years revealed that the horn was actually a modified thumb. Still encased in rock, the Maidstone skeleton is currently displayed at the
Natural History Museum in
London. The borough of Maidstone commemorated this find by adding an
Iguanodon as a
supporter to their
coat of arms in 1949. This specimen has become linked with the name
I. mantelli, a species named in 1832 by
Christian Erich Hermann von Meyer in place of
I. anglicus, but it actually comes from a different
formation than the original
I. mantelli/
I. anglicus material. The Maidstone specimen, also known as Gideon Mantell's "Mantel-piece" and formally labelled as NHMUK 3741, was subsequently excluded from
Iguanodon. It was classified as
cf. Mantellisaurus by McDonald (2012), as cf.
Mantellisaurus atherfieldensis by
David Bruce Norman (2012), In 2021, a sculpture nicknamed Iggy the
Iguanodon based on the Maidstone specimen was unveiled at the
Maidstone East station. The dinosaur is also featured in Maidstone's
coat of arms, and is the only dinosaur featured in a borough's coat of arms in the UK.
Specimen IRSNB 1551 and "Dollodon" Specimen IRSNB 1551 from the
Sainte-Barbe Clays,
Belgium, became the second mounted skeleton of a non-avian dinosaur made primarily out of actual bone when put on display by
Louis Dollo in 1884. This specimen was originally assigned to
Iguanodon mantelli by
George Albert Boulenger in 1881, but was in 1986 thought to pertain to
Iguanodon atherfieldensis by
David Bruce Norman. The specimen was assigned to its own genus and species,
Dollodon bampingi, by
Gregory S. Paul in 2008. The genus was named after Dollo, who first described the remains, and the
specific name was in honour of popular science writer Daniel Bamping, who assisted Paul in his investigations. Paul noted several differences between the
Mantellisaurus type (NHMUK R5764) and IRSNB 1551. The
Mantellisaurus type had proportionally shorter forelimbs with a larger pelvis and he argued it was probably more bipedal, whereas IRSNB 1551 was more likely to be quadrupedal. Paul also noted that the
snout and
trunk of IRSNB 1551 were proportionally longer than the
Mantellisaurus type specimen. Likewise, David B. Norman and Andrew McDonald do not consider
Dollodon a valid
genus or species and instead include it with
Mantellisaurus.
Sauerland specimens In 1971, a fossiliferous
karstic
sinkhole clay deposit was found at a quarry just south-west of the village of
Nehden near
Brilon in
Sauerland, Germany containing numerous disarticulated iguanodontid remains predominantly of
Mantellisaurus with lesser quantities of
Iguanodon, alongside other fragmentary dinosaur and crocodylian material.
Iberian specimens Mantellisaurus is known from several localities in Spain, with an articulated hindlimb known from
Las Hoyas and a specimen known from the Rubielos de Mora 1 locality in Spain. Three specimens are known from the
Arcillas de Morella Formation. ==Description==