Spicule

This article is about the skeletal structure. See also Spicule (solar physics) and Spicule (glass manufacture).

Spicules are tiny spike-like structures of diverse origin and function found in many organisms, such as the copulatory spicules of certain nematodes or the grains on the skin of some frogs.

Main article: sponge spicule

In sponges, spicules perform a structural function.