Great fossil enigma and the mighty neural crest

Conodont microfossils are very small structures looking like spiky teeth, combs and other weird things. Their enigmatic nature was constantly exciting generations of paleontologists since their initial discovery: it was not clear which part of which animals these things do represent. Conodont elements were many, but they were found without association with any other fossils. 

This situation continued for many years while researchers were proposing all possible, sometimes absolutely crazy ideas. The answer came relatively recently, when lucky scientists finally dug out the entire animals containing conodont elements in their mouths. It turned out that these animals were primitive eel-like soft-bodied chordates, which were using conodont elements to bite and retain the prey.

Here is a link to the paper in PNAS by Nicolas Goudemand with coauthors that describes the reconstruction of a conodont mouth apparatus: “Synchrotron-aided reconstruction of the conodont feeding apparatus and implications for the mouth of the first vertebrates”.

http://www.pnas.org/content/108/21/8720.full

Conodonts are specifically interesting since they represent first really solid tissues in the body of early chordates. Based on everything we know today about evolution of the head, it seems that conodonts must be derived from the neural crest stem cells. If true, this might mean that first genetic regulatory network controlling scale formation, making teeth and all other skeletal elements in the body was developed in the neural crest lineage and only later was “borrowed” by the mesoderm. Thus, there is a high chance that all parts of our skeleton are the consequences and, in a way, derivatives of these ancient tooth-like structures called conodont elements. Isn’t it funny to think that the genetic program for making bones in our arms was born to make tiny teeth originating from neuroepithelial tissue?

P.S. Some scientists still doubt that conodonts are true chordates.

"In this way the reconstruction of a minimal discovered form does not indicate how these functions were developed, but it rather points only to the height of the current state, the height of the development, which allows such a deep secondary simplification. Here is an example: imagine a planet that is a home to various geometric shapes, where some high-order fractals that recently underwent a significant evolution decided to understand how the life (geometrical in this case) originated in their world. Exploring the curves of the local flora, including all those growing quadrature cycloids occupying trochoid bushes, hyperbolas and parabolas, polyhedral fauna, including the Platonic bodies - these small cubes hastily escaping from predatory dodecahedrons, geometrical minds came to the conclusion that, most likely, life has evolved from very simple forms. Isn't it nice to imagine a primordial predator as a tetrahedron? Isn't it logical to put a perfect and simple shape in the beginning of the circle of life? In a geometrical way this would be an overgrown point.  ...Then fractal scientists from this planet began to look for the simplest forms of life and have found that it is indeed represented by very simple circles of different sizes. However, looking at those circles with a powerful microscope, they found multiple tiny teeth making up the circles. It turned out that these very simple circles occurred by the reduction of  extremely complicated polyhedrons."
-Ivanov-Petrov (original in Russian http://ivanov-petrov.livejournal.com/1410301.html)

"But I declare that Shakespeare and Raphael are higher than the Emancipation of the Serfs; higher than the concept of nationality; higher than socialism; higher than the younger generation; higher than chemistry; higher, almost, than the whole of mankind; for they are indeed the fruit, the real fruit of the whole of mankind, perhaps, the highest fruit that ever can be. Beauty’s form already achieved, without the achievement of which, I would perhaps not even agree to live...Good Lord!’ he cried throwing up his arms. ‘Ten years ago I shouted exactly the same from a stage in St Petersburg, exactly the same thing, in the very same words, and just like you, they did not understand anything, but laughed and hissed as you are doing now. Dull-witted people, what do you need to enable you to comprehend? Do you know, do you know that humanity could get along without Englishmen, could get along without Germany, and, of course, without the Russians. It could get along without science, without bread, but only one thing, and one thing alone, it could not get on without, and that is beauty; for there would be nothing to do on earth. All mystery is here; all history is here. Science itself could not last a moment without beauty. Do you know this, you who laugh? It would turn into clumsy philistinism. You would not be able to invent a nail!...I shall not yield!’ He yelled absurdly by way of conclusion, and banged his fist on the table with all his might."

F.M. Dostoevsky

Even if our entire Universe is just a dream, it does not change anything. It still exists, even in the mind of a five-dimensional mushroom. Amanita can explore this part of his mind, imagining himself as a man and using scientific methods. Everything that anthropocentric science requires from this "mushroom" is that his dream was consistent, logical, and obeying mathematical laws. This requirement is, indeed, a falsifiable hypothesis, in a contrast to the hypothesis suggesting the existence of a dreaming mushroom.