Cephalodiscus densus

Cephalodiscus densus
Scientific classification
Kingdom:	Animalia
Phylum:	Hemichordata
Class:	Pterobranchia
Order:	Cephalodiscida
Family:	Cephalodiscidae
Genus:	Cephalodiscus
Species:	C. densus
Binomial name
Cephalodiscus densus Andersson, 1907[1]

Cephalodiscus densus is a sessile hemichordate belonging to the order Cephalodiscida.[2] The species is endemic to the Antarctic, being found in the Ross Sea and much of the Antarctic coastline, as well as near the Kerguelen Islands.[3]

Specimens appear bush-like, with fleshy tubules approximately 1 mm in diameter[3] wrapped in a rock shell built of cemented sediment and other foreign material.[4] Individuals live in the upper portion of the shell, and eggs and young are stored in the lower portion, or the colony to which the base attaches.[4] The body is roughly 6 mm long, of which the stalk composes about 4 mm.[3] The preserved flesh appears on average orange in color, with individuals ranging from pale to dark brown.[3][4]

The largest-known colony of peanut worms is a 2.5-m colony of C. densus.[5]

References

1. Andersson K (1907) Die Pterobranchier der Schwedischen Sudpolar-Expedition, 1901-1903. Wissenschaftliche Ergebnisse der Schwedischen Sudpolar-Expedition. Stockholm. pp. 1-122.
2. Swalla, B.J.; van der Land, J. (2020). "Cephalodiscus densus". WoRMS. World Register of Marine Species. Retrieved September 17, 2020.
3. Ridewood, W. G. (October 1921). "On specimens of Cephalodiscus densus dredged by the 'Challenger' in 1874 at Kerguelen Island" (PDF). Annals and Magazine of Natural History. 8 (46): 433–440. doi:10.1080/00222932108632603. ISSN 0374-5481 – via Biodiversity Heritage Library.
4. Schiaparelli, S.; Cattaneo-Vietti, R.; Mierzejewski, P. (2004-11-01). "A "protective shell" around the larval cocoon of Cephalodiscus densus Andersson, 1907 (Graptolithoidea, Hemichordata)" (PDF). Polar Biology. 27 (12): 813–817. doi:10.1007/s00300-004-0661-x. ISSN 1432-2056 – via ResearchGate.
5. McClain, Craig. "Hemichordata (Peanut Worms)". The Story of Size. Archived from the original on 20 February 2020. Retrieved 2023-06-10.