Denticles or placoid scales are small outgrowths which cover the skin of many cartilaginous fish including sharks. They are similar in structure to teeth, and teeth may have evolved from denticle like structures in primative fish. The shape of denticle varies from species to species and can be used in identification. In most biological nomenclature, a scale (Greek lepid) is a small rigid plate that grows out of an animals skin to provide protection. ... Orders see text The Chondrichthyes or cartilaginous fishes are jawed fish with paired fins, paired nostrils, scales, two-chambered hearts, and skeletons made of cartilage. ... Orders Hexanchiformes Squaliformes Pristiophoriformes Squatiniformes Heterodontiformes Orectolobiformes Carcharhiniformes Lamniformes Sharks are a group (superorder Selachimorpha) of fish, with a full cartilaginous skeleton, a streamlined body plan, with normally 5, but up to 7 (depending on species) gill slits along the side of, or beginning slightly behind, the head (in some... Types of teeth Molars are used for grinding up foods Carnassials are used for slicing food. ...

Shark skin, covered in denticles is as rough as sandpaper when stroked from tail to head, and has been used as sandpaper or graters for many years (see Oroshigane). Sharks have been known to use their skin to inflict wounds on prey. Orishigane grater made with shark skin Oroshigane (おろし金 or 下ろし金, Literally: grating-metal), also known as oroshiki are graters for use in the Japanese kitchen. ...

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Microphotograph of skin