Microfossil shark tooth

Photomacrograph of a microfossil shark tooth. Sharks are marine fish in the clade Selachimorpha (or Selachii) and are related to rays. They are predators, found at the top of the marine food chain. Sharks have multiple rows of teeth which move forward to replace a tooth when it is lost, and as a result a shark can shed many teeth in its lifetime. After a tooth is lost, it can become fossilised over thousands of years and is often the only part of a shark to survive as fossils as their skeletons are made of cartilage and not bone. Width of image is 1.2 mm.