Thirty relatively complete iguanodon skeletons were discovered 322m underground in a coal mine in Bernissart, Belgium at the end of the 19th century. Since the bones were still in their original position, it was possible to present the skeletons in ‘lifelike’ poses. They immediately attracted visitors from all over the world!
The Bernissart Iguanodons
English version (French and Dutch versions follow)
Les Iguanodons de Bernissart
De Iguanodons van Bernissart
Pyrite may shine like gold, but it is nothing more than iron sulphide (FeS2) and it is worthless. Hence its nickname, ‘Fool’s Gold’.
The Bernissart iguanodon skeletons were completely filled with pyrite. When clay from the swamps covered the dinosaur corpses, they were decomposed by blue-green algae (cyanobacteria). The acid released reacted with the iron in the clay, thus forming pyrite. It gradually filled the many holes in the bones.
The Cran of the Iguanodons: this was the name of the clay-filled pit containing the skeletons. Several galleries 322m deep were dug. At the entrance to the main one, two iguanodons were discovered in a vertical position with their skulls downwards. The other skeletons, more in the centre, were more or less horizontal. As they were released they were divided into blocks. These – a total of almost 600! – were coated with plaster and taken to the surface in horse-drawn trucks.
During the excavations, the skeletons were divided into blocks of 0.5 – 2m (the contours are visible in this drawing). Each specimen received a letter and each block a number, and their exact positions were recorded. Once the fossils were moved to the Museum workshops, it was possible to return them carefully to their original positions. This depiction of an Iguanodon bernissartensis was drawn by Gustave Lavalette in 1883.
This specimen is a lot smaller than the others. Its skeleton differs slightly from that of the Iguanodon bernissartensis but to be certain that they belong to separate species, we would have to let them mate (if they can reproduce and their offspring are not sterile, they belong to the same species). This is obviously out of the question with creatures that have been dead for millions of years! So the mystery has not been solved.
In 1882, under the direction of Louis Dollo, Louis De Pauw (the man with the beard, bended on one knee) began assembling the most complete specimens in their “probable life posture”. Due to their size, a room with a high ceiling was required. They used the St George chapel (today part of the Royal Library). Here, they built a scaffold hung with ropes. The best position for each bone was obtained by adjusting the length of the ropes. Finally, once the skeleton was assembled, it was fitted with an iron frame to hold the bones in place.
In the 1880s, the Nassau Hotel had become too small to exhibit the iguanodons. The Museum was thus transferred to a building in the Park Leopold: the “Convent”, to which they added the Janlet wing, which is where the iguanodons were kept from 1902 onwards. This photo was taken during its construction in 1900, right about where today’s glass case begins.
The iguanodons have been in the Janlet wing since 1902 but they were exposed to the air until 1932! Due to the temperature and moisture variations they slowly but surely began to crumble. This is why all the skeletons were dismantled between 1933 and 1937 and soaked in a protective mixture of alcohol and shellac. Their brown colour is therefore not the result of being found in a coal mine.
The iguanodon skeletons were dismantled once again in 1940: it was feared they might be damaged or even completely destroyed during the bombings. They were kept in cellars whose openings were protected by sandbags. But it was so damp that they had to be returned to the room before the end of the Second World War!
If you than look, in more details, the hand : it's quite clear the bones of the centre of the hand, the metacarpals, are tied together extremely powerfully by ligaments, to form a weight supporting structure.
The bones of the wrist, are actually build as a series of bricklayer's, and the ligaments, the soft tissues that run around the wrist to protect the wrist bones themselves, have actually ossified, they've turned from being soft tissue into strands of bone.
These actually forming an incredibly powerful support for the weight that is being transmitted through the access of the hand from the shoulders down to the toes.
Finally, you have the extraordinary thumb, this bone is modified into a large conical spike, which actually comes out from the wrist itself, this would be covered by a very sharp horny sheath.
That thumb would be a devastating weapon, especially during combat with predators that would try to prey on the iguanodon.