Smithsonian Marine Station at Fort Pierce

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SEM of Hippoporina verrilli, an encrusting bryozoan. Note the pores perforating the frontal surface, and the distinct umbo inferior to each orifice. Photo by J. Winston, courtesy of the American Museum of Natural History. Used with permission.

Species Name: Hippoporina verrilli Maturo and Schopf, 1968
Common Name: None
Synonymy: None

    Kingdom Phylum/Division Class: Order: Family: Genus:
    Animalia Ectoprocta Gymnolaemata Cheilostomata Hippoporinidae Hippoporina

    Other Taxonomic Groupings

    Voucher Specimen: American Museum of Natural History
    Suborder: Ascophora

    Species Description

    H. verrilli colonies are calcified and encrusting. Individual zooids are regular in shape, and generally quadrangular. Zooids measure an average of 0.40 X 0.29 mm, but older colonies grow as large as 0.47 X 0.39 mm. A slightly raised rim separates zooids from each other. Ten to twenty regularly-spaced pores perforate the frontal surface of individual zooids. The orifice is rounded distally, with a slightly curved proximal portion. There is often an umbo just inferior to the orifice. The lophophore measures approximately 0.428 mm in diameter and bears 12 tentacles. avicularia are highly variable, or absent in some colonies. If they are present, they may occur on either side, or on both sides of the orifice. Avicularia may be narrow; ovoid, or have round bases with triangular mandibles. The narrow type is generally directed proximolaterally; the other types can have a variety of orientations. Living specimens from the IRL area are ivory or beige in color. However, specimens from other areas vary from shades of yellow to red.


    Regional Occurrence

    H. verrilli is widely distributed in warm temperate to tropical waters, and is especially common in brackish water areas. In the western Atlantic, it is found from Cape Cod south to Brazil. In the Pacific, it is found from the Gulf of California to the Galapagos Islands, Ecuador.

    IRL Distribution

    H. verrilli is a highly abundant and well known fouling organism within the Indian River Lagoon.


    Age, Size, Lifespan

    Zooids measure an average of 0.40 X 0.29 mm, but older colonies grow as large as 0.47 X 0.39 mm. The frontal surface of individual zooids is perforated by 10 - 20 regularly spaced pores. The lophophore measures approximately 0.428 mm in diameter and bears 12 tentacles.


    H. verrilli is one of the most abundant bryozoan species in the Indian River Lagoon. It occurs most commonly from October through June, with greatest abundance in the Fall.




    The heaviest period of larval settlement in this species is in Fall, from October through January, though new colonies continue to settle through June.


    Globular ovicells are present. These are hyperstomial and have rough calcification around the outside, with a smoother, porous central area. The central area may become secondarily calcified. Embryos are a red-orange color.



    H. verrilli is eurythermal, with its period of heaviest reproduction occurring in cooler months.


    H. verrilli is commonly collected in areas where salinity falls below 30‰.


    Trophic Mode

    H. verrilli, like all bryozoans, is a suspension feeder. Each individual zooid in a colony has 12 ciliated tentacles which 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). H. verrilli was typically found encrusting wood, shell and other hard substrata.

    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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