Stylet (anatomy)

A stylet is a hard, sharp, anatomical structure found in some invertebrates. For example, the word stylet or stomatostyle is used for the primitive piercing mouthparts of some nematodes and some nemerteans. In these groups the stylet is a hardened protrusible opening to the stomach.

The mouthparts of tardigrades and aphids are also called stylets.

The stylet is adapted for the piercing of cell walls, and usually functions by providing the operative organism with access to the nutrients contained within the prey cell.