The Changing Shape of a Dinosaur Mantell's First Impressions

In 1834 Mantell received the news that Iguanodon remains had been discovered in a pit in Maidstone.   Before he could get there, the rock had been dynamited, but a large number of bones remained embedded in a block of rock. The quarry owner wanted £25.00 for the slab of rock, and Mantells friends clubbed together and bought it for him.  

He set about the task of trying to reconstruct the Iguanodon on paper from the bones held on this slab of rock. It became known as the Maidstone Slab, and was placed on display in Mantell's personal museum where it became known as the 'Mantle-piece'.   It is nowadays on display in the Dinosaur Gallery at the Natural History Museum in London.

Mantells early drawings of Iguanodon are based largely on this evidence, and are quite inaccurate.  Incidentally, the town of Maidstone has an Iguanodon on its coat of arms as a tribute to the discovery.

Mantells first drawings of his Iguanodon showed a creature resembling an iguana lizard.   The creature was drawn as a quadruped - standing on four legs.

Mantell's first attempt at drawing an Iguanodon Note the 'horn' positioned on the snout of the creature

The 'horn', found by Mantell's wife, resembled a rhinoceros horn and prompted Mantell to presume that it was from the creature's snout, especially as that is where a spike is found on an iguana.

Later discoveries in Belgium in 1878 (the Bernissart iguanodon) would show that the 'horn' was actually a thumb spike.

The Iguanodon 'horn'