Classification

- Sipunculans, in the past, were considered part of the Annelid phyla, despite lacking segmentation and bristles among other annelid characteristics.

- Later, they were thought to be more closely related to the phyla Mollusca based on their developmental and larval characteristics.

- In 1959, they were placed in their own phylum

- There are four families within the phyla

- Kingdom Animalia

Eumetazoa (Metazoans)

Billateria

Protostomia

Lophotrochozoa

Phylum Sipuncula

Family Aspidociphonidae

Family Golfingiidae

Family Sipunculidae

Family Phascolosomatidae