Smithsonian Marine Station at Fort Pierce

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Growth pattern of Amathia vidovici. Drawing by J. Winston, courtesy of American Museum of Natural History.
Used with permission.

Species Name: Amathia vidovici Heller, 1867
Common Name: None
Synonymy: None

    Kingdom Phylum/Division Class: Order: Family: Genus:
    Animalia Ectoprocta Gymnolaemata Ctenostomata Vesiculariidae Amathia

    Other Taxonomic Groupings

    Suborder: Carnosa
    Superfamily: Vesicularioidea

    Potentially Misidentified Species

    Superficially resembles Amathia distans, but has a wider stolon with somewhat stiffer branches.

    Species Description

    A. vidovici is an arborescent bryozoan that forms branching, semi-erect colonies. Stolons in this species are wider than in A. distans and measure approximately 0.13 - 0.20 mm. Zooids measure approximately 0.4 mm in height, and are connected to the stolon for only part of their length.

    They are arranged in small clumps of 4 - 8 pairs and turn partially around the axis of the stolon at the distal (far) end. The proximal (near) end of the stolon often remains bare. Color is from white to tan, with light chitinization apparent.


    Regional Occurrence

    A. vidovici is highly cosmopolitan and occurs in the western Atlantic from Massachusetts south to the Gulf of Mexico and the Caribbean. In the Pacific Ocean, it occurs from California to the Galapagos Islands. It is also found in the Mediterranean, the eastern Atlantic, and the Indian Ocean.

    IRL Distribution

    A. vidovici is found year-round in the Indian River Lagoon between Sebastian and Ft. Pierce Inlets. Coastally it has been collected at Seminole Shores and other sites. It is also commonly observed in the spring attached to the Rhodophyte Solieria tenera in the Sebastian seagrass flats.


    Age, Size, Lifespan

    Individual zooids measure approximately 0.4 mm in height. Stolons are wider than those of A. distans and measure 0.3 - 0.20 mm.


    A. vidovici is one of the most abundant bryozoans in the Indian River Lagoon (Winston 1995). It is most common in the winter months.




    The embryology of A. alternata is unknown.



    As a highly cosmopolitan species, A. vidovici is considered to be eurythermal.


    A. vidovici was typically collected in areas where salinity exceeded 30‰ (Winston 1995).


    Trophic Mode

    A. vidovici, like all bryozoans, is a suspension feeder. Each individual zooid in a colony has ciliated tentacles that are extended to filter phytoplankton less than 0.045 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.


    Typical habitat for ectoprocts in the Indian River Lagoon include seagrasses, drift algae, oyster reef, dock, pilings, breakwaters, and man-made debris (Winston 1995). A. vidovici occurring in the IRL were collected from rocks, seagrasses and algae.

    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.


    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.


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

Report by: K. Hill, Smithsonian Marine Station
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Page last updated: July 25, 2001

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