Misconception About Sharks Fossil
There is a common misconception among individuals about sharks fossil specially when the question appears, 'Why teeth is the common elements of sharks to be fossilized ?'. An average percentage of people think only teeth of a shark can be fossilized because the maximum amount of fossils regarding sharks were collected as teeth's. The reason behind this fact is, shark's skeleton is actually made of cartilage like other marine fishes. It is quite similar to the bone fragments from which our ear, nose are made. The problem with the cartilage is, they gets decomposed easily as they cannot mineralize quickly as bone can . And yes teeth is a common bony fragment. That's why in maximum or most of the cases teeth's can be found as fossils. But here is a fact that, the procedure of fossilizing is much more dependent on the environment. If a cartilage can get dumped under sediments, quicker than normal geological process, it can be preserved. So, the whole thing is, teeth's are not the only part that gets fossilized in case of sharks. For better understanding we have provided a slide-show below.
References:
1. http://www.flmnh.ufl.edu/fish/discover/sharks/fossil-sharks/fossil-vs-modern
2. http://www.fossilguy.com/gallery/vert/fish-shark/remnant.htm
1. http://www.flmnh.ufl.edu/fish/discover/sharks/fossil-sharks/fossil-vs-modern
2. http://www.fossilguy.com/gallery/vert/fish-shark/remnant.htm