Sipuncula is a phylum of unsegmented marine worms with a retractable introvert and a gut that is wound back on itself to an anus at the anterior end of the trunk.
Keywords: peanut worms; minor phylum; benthos
Sipuncula (Unsegmented Marine Worms)
Edward B Cutler, Harvard University, Cambridge, Massachusetts, USA
Published online: April 2001
DOI: 10.1038/npg.els.0001600
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Figure 1. Sipunculan external form showing variation within the genus Themiste. Broad trunk, with more slender retractable introvert, and terminal tentacles.
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Figure 2. Internal organs of stylized sipunculan. Variation among taxa includes number of retractor muscles, arrangement of spindle muscle, nature of body wall muscle layers, and number/size of nephridia.
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| Further Reading | |
| book Cutler EB (1994) The Sipuncula, their Systematics, Biology and Evolution. Ithaca, NY: Cornell University Press. | |
| Cutler EB and Cutler NJ (1987) Deep-water Sipuncula from the eastern Atlantic Ocean. Sarsia 72: 71–89. | |
| Cutler EB and Gibbs PE (1985) A phylogenetic analysis of higher taxa in the phylum Sipuncula. Systematic Zoology 34: 162–173. | |
| book Rice ME (1983) "Sipuncula". In: Adiyodi KG and Adiyodi RG (eds) Reproductive Biology of Invertebrates: Oogenesis, Oviposition and Oosorption, pp. 283–296. New York: John Wiley and Sons. | |
| book Rice ME (1993) "Sipuncula". In: Harrison FW and Rice ME (eds) Microscopic Anatomy of Invertebrates, vol. 12: Onychophora, Chilopoda, and Lesser Protostomata, pp. 238–325. New York: Wiley-Liss. | |
| Scheltema AH (1993) Aplacophora as progenetic aculiferans and the coelomate origin of mollusks as the sister taxon of Sipuncula. Biological Bulletin (Woods Hole) 184(1): 57–78. | |
| book Stephen AC and Edmonds SJ (1972) The Phyla Sipuncula and Echiura. London: Trustees of the British Museum (Natural History). | |
