Schizobranchia

Taxobox
name = "Schizobranchia insignis"


image_width = 250px
regnum = Animalia
phylum = Annelida
classis = Polychaeta
ordo = Sabellida
familia = Sabellidae
genus = "Schizobranchia"
species = "S. insignis"
binomial = "Schizobranchia insignis"
binomial_authority = (Bush, 1905)

"Schizobranchia insignis" is a marine Feather Duster Worm.

Common Names

Split-Branch Feather Duster, Split-Plume Feather Duster, Feather Duster Worm

Description

Tube is 10-20 cm long, 5-10 mm in diameter, whitish and pliable. Color of tentacular crown is uniform orange, red, mauve, tan, brown, grey, or green.

Geographic Distribution

Alaska to Central California.

Habitat

Commonly found living attached to pilings and rocks, intertidal to 46 m. Abundant on the underside of wharves in Puget Sound. Can be found on wharves at Boston Harbor marina.

Life History

"Schizobranchia insignis" is free-spawning, releasing gametes into the water column for fertilization. [Thomas, F., 1998. Transport and mixing of gametes in three free-spawning polychaete annelids, "Phragmatopoma californica" (Fewkes), "Sabellaria cementarium" (Moore), and "Schizobranchia insignis" (Bush). "Journal of Experimental Marine Biology and Ecology". 179, 1: 11-27.] If disturbed by touch, water movement, or shadow, the tentacular crown can be quickly withdrawn entirely within the tube, by retractor muscles. Ciliated radioles (feathery tentacles) collect planktonic particles, which are trapped in mucus and carried to the mouth.

Physiology and Biochemistry

"Schizobranchia insignis" has been found to accumulate dissolved carbon exuded by an alga. [Fankboner, P.V. & L.D. Druehl, 1976. In situ accumulation of marine algal exudate by a polychaete worm ("Schizobranchia insignis"). "Cellular and Molecular Life Sciences". 32, 11: 1391-1392.] For feeding and respiration, "S. insignis" reportedly passes 70 ml/hr/g animal (fresh weight) of water through the tentacular crown by the cilia's movement. [Phillips Dales, R., 1961. Observations on the respiration of the sabellid polycheate "Schizobranchia insignis". "Biological Bulletin". 121: 82-91.] The hooked setae of "Schizobranchia insignis" have been found to dig into the tube wall and serve as anchors, likely to secure the worm from being sucked out by a fish or pulled by wave action. Worms were found to withstand high pressures of 100-200 kPa (applied experimentally, from posterior). [Merz, R.A. & S.A. Woodin, 2000. Hooked setae: tests of the anchor hypothesis. "Invertebrate Biology". 119, 1: 67-82.]

Ecosystem Role

Along with other species of polychaete worms, "S. insignis" is host to kleptoparasitic suspension-feeding snails, like "Trichotropis cancellata", that live on the worms and steal food. [Iyengar, E.V., 2004. Host-specific performance and host use in the kleptoparasitic marine snail "Trichotropis cancellata". "Oecologia". 138, 4: 628-639.]

Identification

Among Pacific Northwest sabellids, "S. insignis" is unique in that all radioles are dichotomously branched at least once. Radioles of "Eudistylia polymorpha" are not branched, and only a few of the radioles of "E. vancouveri" are branched.

Footnotes

External Links

* [http://www.nwmarinelife.com/htmlswimmers/s_insignis.html photo of "S. insignis" (Intertidal Marine Invertebrates of the South Puget Sound)]
* [http://research.calacademy.org/research/izg/sfbay2k/Two%20Sabellids.htm photo of "S. insignis" (California Academy of Sciences)]

References and More Information

* Brusca, R.C. & G.J. Brusca, 2003. "Invertebrates". Sinauer Associates, Inc, Sunderland, Massachusetts.

* Kozloff, E. N., 1996. "Marine Invertebrates of the Pacific Northwest". University of Washington Press, Seattle, Washington.

* Kozloff, E. N., 2000. "Seashore Life of the Northern Pacific Coast". University of Washington Press, Seattle, Washington.

* Lamb, A. & Hanby, B.P., 2005. "Marine Life of the Pacific Northwest: a photographic encyclopedia". Harbour Publishing, British Columbia.