The curved bottom of the "foot" faces outward, while a cylindrical column at the base anchors the denticle to the shark's body. The outward shape of denticles was long believed to reduce drag ...

A rostral denticle of Ischyrhiza mia, a species belonging to an extinct group of sawfishes that lived in North American waters during the late Cretaceous period, around 100 to 65 million years ago.