how many rows of teeth to sharks have
Shark tooth In taxonomy, shark teeth are counted as follows: rows of teeth are counted along the line of the jaw, while series of teeth are counted from the front of the jaw inward.[11] A single tooth row includes one or more functional teeth at the front of the jaw, and multiple replacement teeth behind this.[12] For example, the jaws of a bull shark can have 50 rows of teeth in 7 series, with the outermost series functional, but most sharks have five series with the average shark having about 15 rows of teeth in each jaw.[9] The small teeth at the symphysis, where the two halves of the jaw meet, are usually counted separately from the main teeth on either side. Sharks are also known to lose at least one tooth per week. Due to their specific arrangement of rows and series however, lost teeth can be replaced within a day.[9]
Mandible In lobe-finned fishes and the early fossil tetrapods, the bone homologous to the mandible of mammals is merely the largest of several bones in the lower jaw. In such animals, it is referred to as the dentary bone, and forms the body of the outer surface of the jaw. It is bordered below by a number of splenial bones, while the angle of the jaw is formed by a lower angular bone and a suprangular bone just above it. The inner surface of the jaw is lined by a prearticular bone, while the articular bone forms the articulation with the skull proper. Finally a set of three narrow coronoid bones lie above the prearticular bone. As the name implies, the majority of the teeth are attached to the dentary, but there are commonly also teeth on the coronoid bones, and sometimes on the prearticular as well.[8]