Shark teeth like these are common in the fossil record for two reasons. First, just like modern sharks, prehistoric sharks had an unlimited supply of teeth. As a tooth became worn, it would fall out, to be replaced by another growing in a row behind. Second, since the skeleton of a shark is made mostly of cartilage, flexible connective tissue that is not bone and doesn't usually fossilize, it is common to find just the teeth. It is difficult to identify which kind of shark a tooth came from because the shape of the tooth may vary depending on where in the mouth the tooth came from, how much wear was on the tooth, and how well the fossil was preserved.
The Children's Museum of Indianapolis
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