Stingray or skate (Batoidea) fossilised tooth

Photomacrograph of a stingray or skate (Batoid) fossilised tooth. Stingrays and skates belong to the Batoidea superfamily which contains cartilaginous fish. They have developed flattened teeth with blunt crowns in order to crush their prey, hard-shelled crustaceans. After a tooth is lost or when the fish dies, teeth can become fossilised over thousands of years.