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SEM of Membranipora savartii, an encrusting bryozoan. Note heavy calcification and pattern of fine tubercles along the frontal surface. Photo by J. Winston, courtesy of the American Museum of Natural History. Used with permission.

Species Name: Membranipora savartii Audouin, 1926
Common Name: None
Synonymy: None
  1. TAXONOMY

    Kingdom Phylum/Division Class: Order: Family: Genus:
    Animalia Ectoprocta Gymnolaemata Cheilostomata Membraniporidae Membranipora

    Other Taxonomic Groupings

    Suborder: Anasca

    Voucher Specimen

    American Museum of Natural History # 579

    Species Description

    M. savartii forms encrusting colonies that may be one or more layers thick. Zooid shape varies from elongate to rectangular or quadrangular. Individuals measure an average of 0.27 X 0.55 mm. A variable denticulated (toothed) shelf is formed under the proximal half of the frontal surface. Proximal teeth are variable in number or absent. Zooid walls are heavily calcified and have fine tubercles. No avicularia are present.

  2. HABITAT AND DISTRIBUTION

    Regional Occurrence

    M. savartii is highly cosmopolitan in warm water areas. In the western Atlantic, it ranges from the Carolinas to Brazil, including Florida, the Gulf of Mexico and the Caribbean.

    IRL Distribution

    M. savartii was collected from the Sebastian Inlet area, both at the inlet, and in the adjacent grass flat areas (Winston 1982). It was also collected from coastal stations at Walton Rocks, Seminole Shores, and on Capron Shoals.

  3. LIFE HISTORY AND POPULATION BIOLOGY

    Age, Size, Lifespan

    Individual zooids measure an average of 0.27 X 0.55 mm.

    Abundance

    M. savartii occurs year round, but is most abundant in April and October. In the IRL, it is considered a fouling organism (Winston 1995).

    Locomotion

    Sessile

    Reproduction

    No ovicells are present in this species. Like other membraniporids, Membranipora savartii spawns small eggs which develop into planktonic cyphonautes larvae.

  4. PHYSICAL TOLERANCES

    Temperature

    As it is present year-round,

    M. savartii is considered to be eurythermal.

    Salinity

    M. savartii was typically collected in areas where salinity exceeded 30‰ (Winston 1995).

  5. COMMUNITY ECOLOGY

    Trophic Mode

    M. savartii, like all bryozoans, is a suspension feeder. Each individual zooid in a colony has ciliated tentacles that are extended to filter phytoplankton less than 0.05 mm in size (about 1/1800 of an inch) from the water column. Bullivant (1967; 1968) showed that the average individual zooid in a colony can clear 8.8 ml of water per day.

    Habitats

    Typical habitat for ectoprocts in the Indian River Lagoon include seagrasses, drift algae, oyster reef, dock, pilings, breakwaters, and man-made debris (Winston 1995). M. savartii was typically found on dead shells and rock substrata at all locations (Winston 1982).

    Associated Species

    Seagrasses as well as floating macroalgae, provide support for bryozoan colonies. In turn, bryozoans provide habitat for many species of juvenile fishes and their invertebrate prey such as polychaete worms, amphipods and copepods (Winston 1995).

    Bryozoans are also found in association with other species that act as support structures: mangrove roots, oyster beds, mussels, etc.

  6. ADDITIONAL INFORMATION

    Benefit in IRL

    Bryozoans are ecologically important in the Indian River Lagoon due to their feeding method. As suspension feeders, they act as living filters in the marine environment. For example, Winston (1995) reported that bryozoan colonies located in 1 square meter of seagrass bed could potentially filter and recirculate an average of 48,000 gallons of seawater per day.

  7. REFERENCES

    Winston JE. 1982. Marine bryozoans (Ectoprocta) of the Indian River area (Florida). Bull Amer Mus Nat Hist 173: 99-176.

    Winston JE. 1995. Ectoproct diversity of the Indian River coastal lagoon. Bull Mar Sci 57: 84-93.

Report by: K. Hill, Smithsonian Marine Station
Submit additional information, photos or comments to:
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Page last updated: July 25, 2001

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