Fossils can tell us so much about the history of life on Earth. They can help us identify where the beginnings of great groups of animals began; tell us about wonderful animals and plants that once lived; and reconstruct environments long vanished. They are the all that remains of a once living thing. That is pretty amazing to think about; a long, long time ago, this was actually a breathing, moving, eating real thing.
Fossils are pretty rare. To become a fossil the organism (that is, the living thing) has to drop dead in just the right environment, preferably one which covers it really quickly with sediment so scavengers won’t rip apart the body. Fine sediment is best to preserve the finer detail, as coarse sand grains can gently and slowly rub against soft parts. Then it has to be buried deep under more sediment and not disturbed. Slowly water is squeezed out of the sediment under the enormous weight of more sediment above. (Imagine a wet t-shirt, fold it in half, and lay it on a table. Put a book on top. And then another, and another, eventually the weight of the books will squeeze all the water out.) As water is squeezed and pushed it moves through the sediment, and if there happens to be the remains of a long dead organism, minerals in the water are deposited creating an exact replica of the dead organism; the fossil. Sometimes the minerals can replace even the smallest details of an animal, literally turning it to stone. More often than not all we are left with is the hard parts, some bones, shells and teeth. That is, if we are lucky to find them.
Unfortunately not all museums lie on top of an ancient graveyard of extinct creatures. To compensate, they may buy specimens that represent the main group (which are usually pretty low quality). Or they buy casts.
For something so incredible as discovering the evidence for a long lost animal millions of years ago, it is such a shame early casts of these remains were so bad. Sometimes, however, the fossils themselves may be truly bad.
This weeks bad cast is bad, but the real fossil isn’t much better.
Here is the ‘top’ (or maybe the side?) which shows a little more detail. Just a little.
You may be surprised to know it is actually a real cast of a fossil fish tooth. This fossil fish, a shark known as Psammodus rugosus, lived during the Carboniferous Period (around 350 million years ago). The cast does actually portray the really fossil fairly well, as you can see here.
Actually researching information for this shell crunching shark didn’t turn up much at all. I guess the internet doesn’t have much to say about a rather dull looking, flat shark tooth. It does get a hit on Google books, from a book written in 1843. Exciting, and no doubt a riveting read.
The fossil does crop up on the wonderful Grant Museum’s ‘Underwhelming Fossil Fish of the month’ blog (here). It appears there is not much to say about this ancient creature by the Grant Museum either.
Which begs the question of why, oh sweet lord why, would someone authorise money being spend on something that looks like a delicious chunk of honeycomb toffee? (Of all the chocolate bars, those with honeycomb centres are my weakness. And ones with coconut. And fudge. And Toblerone. I really like Toblerone with honeycomb bits.)
Although this fossil cast (and perhaps the real fossil too) doesn’t get you excited, it is all that remains of a shark that actually swam around over 350 million years ago. It may be a bad cast, but this represents something that once lived.