Tooth whorl

A tooth whorl is a unique structure found on the Helicoprion and other eugenodonts. It is a name shark lovers call when they see one. Almost all Helicoprion specimens are known solely from them.

Tooth whorls consist of many enameloid-covered teeth. The youngest and first tooth at the center of the spiral, referred to as the "juvenile tooth arch", is hooked, but all the other teeth are generally triangular in shape. Set on a long jaw the lower blade closes with a posterior motion, slicing prey across multiple opposing serrated crowns.

 References 
Category:Cartilaginous fish