Pectinatella magnifica, the magnificent bryozoan, is one of the more unusual species in the bryozoan family (Ectoprocta). Bryozoans are small filter feeding invertebrates that live as colonies aquatic habitats. Other invertebrates (such as corals and ascidians) also live in colonies of many individuals, however while ecologically similar bryozoans, corals and ascidians are in different phyla and not closely related. Of the several thousand species of bryozoans, almost all live in marine environments, however the 19 species in the class Phylactolaemata (one of which is P. magnifica) are found exclusively in freshwater.
The magnificent bryozoan is native to North America, originally to lakes and rivers east of the Mississippi. Within the last 30 years however, it has become established in freshwater systems in the western US, in Texas, Oregon, Idaho and Washington, and has been found in Canada, Europe and Asia (Wood 2010; Cannister 2013). There is some concern that this species is becoming more common in areas outside its range, for reasons yet unknown (Virginia Institute of Marine Science 2010)
Colonies of magnificent bryozoans form on the surface of a central jelly-like blob made up of mostly water, with the individual animals (called zoids) living in “rosettes” of 10-18 individuals. As with all bryozoans, each individual filter feeds by straining small particles from the water using a lophophore organ characteristic of the ectoprocts. Pectinatella magnifica colonies can grow large, more than two feet (60 cm) across, usually found attached to an underwater substrate, but also free floating. One study has found that these colonies can propel themselves through the water by creating currents with coordinated beating of the ciliated tentacles on the lophophores. Magnificent bryozoan colonies are found as a firm but slimy translucent brown mass with black dots sprinkled throughout.
While P. magnifica does not impose great impact on humans, large masses of magnificent bryozoans can clog drains and waterpipes, and when washed up on land have a fishy smell. Because the individual zoids remove particles from the water, the immediate effect result of greater occurrence in non-native waters is to increase water quality. A longer term effect, however, is that clearer waters may promote increase of algae which now have access to more sunlight and better conditions for photosynthesizing. This may restructure natural ecosystems in bodies of water.
Link to the EOL Bryozoa page for more information about general biology of bryozoans.
- Neck, R. and R. Fullington. 1983. New records of the freshwater ectoproct Pectinatella magnifica in eastern Texas. Texas J. Sci. 35:269-271.
- Cannister, M. 2013. Pectinatella magnifica. USGS Nonindigenous Aquatic Species Database, Gainesville, FL. Retrieved June 11 2013 from
- http://nas.er.usgs.gov/queries/FactSheet.aspx?speciesID=2335 Revision Date: 2/7/2011
- Virginia Institute of Marine Science (2010, November 1). Mystery of 'alien pod' solved: Colony of freshwater bryozoans. ScienceDaily. Retrieved June 11, 2013, from http://www.sciencedaily.com /releases/2010/11/101101142517.htm
- Wood, T. S. Bryozoans. Pages 437-454 in Thorp, J. H. and A. P. Covich (eds.), 2010. Ecology and Classification of North American Freshwater Invertebrates. Academic Press, Inc., San Diego, 1021 pp.