On one day a week, every week of the year, something magical happens. Twitter comes alive with beautiful remains of creatures that lived millions of years ago. The Twitter regulars know this as #FossilFriday, and no doubt salivate at the very thought that on Friday a plethora of enigmatic beasts will jaunt through their timelines with stunning perfection.
All the photos tweeted on #FossilFriday are amazing. We see photos of fossils from long, long ago (like trilobites and ammonites), and others of more recent beasts that roamed only a few tens of thousands of years ago (like cave lions and mammoths), and some of fossils of marks in the sediment made by creatures long ago. All the fossils are beautiful and each is unique. Watching the feed dance with exotic creatures that were once alive long ago every Friday is pure awesomeness.
It was one of these wonderful Fridays, amongst the incredible photographs being tweeted and retweeted, that something jumped out, which was tweeted by the Natural History Museum team (@NHM_London). At first glance they may not look like much, but these are stunningly exquisite fossils, which were actually some of the most important fossils finds of the early 1800s.

Two teeth that were used to define a whole new group of unbelievable animals. (Image reproduced from here)
This particular photograph jumped out because I recognised it instantly with pure awe. They are two teeth of one of the first dinosaurs ever discovered and named; Iguanodon. What is even more exciting, is that we have a rather bad cast in our museum, of the tooth on the right!!
So for one of the most amazing fossil teeth discovered, we have this very unworthy cast! I’m still not to sure how the guys who made these casts got away with it! What’s even more frustrating is that sometimes with a specimen there is an old card record which gives a little more information; the card should have a lot of information on it, however most of the time this is what we have;

A card record which accompanies the fossil cast. You may like to note any lack of information about the original it was cast from, related stories, when it was cast, who did the casting…Just general useful bits of information.
The information on this card is like me saying ‘I am a human’, and not actually saying where I was born, who made me, when I grew up, where my grandparents lived…. These bits of information are key to bringing specimens alive with stories. As it stands, Mr J Gregory has a ruddy lot to answer for. (That chap and A. G. F. Gregory sold us an awful lot of bad casts back in 1906 *shakes fists*.)
Fortunately, there is a quick witted museum curator is on hand to delve into the sparkling history of this little cast.
These teeth were found by Mary Mantell along the roadside in Sussex in 1820 (or 1821 – the records are not too clear). The tale goes that she was with her husband while he was on his medical rounds. She noticed the strange rock and moved the grains with her fingertips to reveal, for the first time in over 125 million years, a shiny, dark brown tooth. The husband, Gideon Mantell, had been finding very large bones in the rocks of the Sussex Downs. These teeth, he immediately thought, could be the teeth of this unknown giant he had been finding, so he devoted the next few years to looking for more specimens.

The determined, passionate fossil hunter Gideon Mantell. (Image from here)
Mantell had passed his fossil finds to the top leading scientists of the time, including William Buckland, Charles Lyell and the great French anatomist, Georges Cuvier. They didnt think much of the fossils, with the identifications ranging from fish teeth to rhinoceros teeth. But in 1824, the assistant curator at the Royal College of Surgeons recognised that these fossil teeth were very similar to the teeth of an iguana; but they were over 20 times as big!
More fossils came to the surface, including some nice specimens from Maidstone in Kent. With the new finds, and confidence about what he had, Mantell presented a paper to the Royal Geological Society of London in 1825, where he named his beast Iguanodon (meaning ‘iguana tooth’)
This was quite a find. An enormous reptile, which was a herbivore (plant eater). This was only the second very large reptile to be named. The previous year, William Buckland has named a big carnivore Megalosaurus (meaning ‘great lizard’). 6 years after his paper on Iguanodon, Mantell discovered the fossil remains of another giant lizard which he named Hylaeosaurus (meaning ‘belonging to the forest’).
What were these three great lizards? Nothing living looked anything like these giants. One man took it upon himself to name the group to place these extraordinary animals in. The man was Richard Owen.

The rather sinister looking Richard Owen. It’s the eyes. (Image reproduced from here)
Owen was a brilliantly intelligent anatomist in the mid-1800s. Owen was a genius; he could identify extinct creatures from a single bone. However, he also ruffled many feathers, include Darwin and Huxley. And Gideon Mantel.
Owen gave a lecture to a large audience at the British Association for the Advancement of Science in Plymouth about these massive lizards. It was in this lecture that he first used the name ‘Dinosauria’ (meaning ‘terrible lizards). He coined this term based on the three animals that had been discovered. Their size and forms were unlike anything known living or extinct, and were distinguishable enough to place them into a completely new group of animals; the Dinosaurs.
These amazing teeth played a vital role in the naming of one of the most familiar species of animals that live on Earth; Iguanodon. The teeth, which had caused so much debate about what they actually were, were also important in coining the name of the most familiar group of animals on the planet; the dinosaurs. This group started off with three know species, and has grown enormously into well over 1000 species identified in the fossil record (not including the birds).
This cast represents one of the most important palaeontological discoveries ever made. It is such a shame it is so bad.