Shark teeth are relics of shark evolution and biology, and as they are often the only part of the shark to survive fossilisation, represent much of the Selachimorpha fossil record, extending back hundreds of millions of years. The most ancient types of sharks date back to 450 million years ago during the Late Ordovician period, and they are mostly known from their fossilised teeth. The most common, however, are from the Cenozoic (65 million years...
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Shark teeth are relics of shark evolution and biology, and as they are often the only part of the shark to survive fossilisation, represent much of the Selachimorpha fossil record, extending back hundreds of millions of years. The most ancient types of sharks date back to 450 million years ago during the Late Ordovician period, and they are mostly known from their fossilised teeth. The most common, however, are from the Cenozoic (65 million years ago). Sharks continually shed their teeth, and some Carchariniformes can shed approximately 35,000 teeth in a lifetime.
Sharks, as well as other Chondrichthyes, have a polyphydont dentition, in which old teeth are shed continually throughout the fish's lifetime, and new ones are rotated into place on a conveyor belt-like structure. Shark teeth, through the same mechanism as the scales on sharks' skin, develop along the inner surface of the jaw cartilage, and are attached to the dental membrane. When the tooth forms in the gum tissue, the...
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