Acicula

This article is about a bristle-worm anatomical feature. For the snail of Aciculidae family, see Acicula (gastropod).

Acicula (sg.: aciculum) are strong, stout internal chaetae that provide support to parapodia in polychaete annelids.^[1]

Microscope photograph of a parapodium from a specimen of Arctonoe sp. showing the internal acicula that support the two lobes of the parapodium.

References

1. Hutchings, P. A.; Fauchald, K. (2000). Polychaetes and Allies: the Southern Synthesis - Class Polychaeata: Definition and General Description. Melbourne: CSIRO Publishing. pp. 1–3.