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SEM of Electra bellula showing the characteristic pattern of branching spines projecting over the proximal ends of the opesia. Photo by J. Winston, courtesy of the American Museum of Natural History. Used with permission.

Species Name: Electra bellula
Common Name: Hincks, 1881
Synonymy: None
  1. TAXONOMY

    Kingdom Phylum/Division Class: Order: Family: Genus:
    Animalia Ectoprocta Gymnolaemata Cheilostomata Electridae Electra

    Voucher Specimen: American Museum of Natural History # 585.
    Other Taxonomic Groupings: Suborder: Anasca

    Species Description

    E. bellula forms encrusting colonies that are lightly calcified and transparent in appearance. Zooids measure approximately 0.18 X 0.34 mm in size. There are usually 2 distal spines, but possibly more, which project from the proximal gymnocyst region. A branched spine often projects over the proximal end of the opesia. The lophophore measures an average of 0.225 mm in diameter and bears 10 tentacles.

  2. HABITAT AND DISTRIBUTION

    Regional Occurrence

    E. bellula occurs in the western Atlantic from Florida to Brazil, including the Gulf of Mexico and the Caribbean.

    IRL Distribution

    E. bellula occurs year round from the Ft. Pierce and St. Lucie inlet areas. It is typically collected on seagrasses, primarily Syringodium species.

  3. LIFE HISTORY AND POPULATION BIOLOGY

    Age, Size, Lifespan

    Zooids measure approximately 0.18 X 0.34 mm in size. The lophophore measures an average of 0.225 mm in diameter, and bears 10 tentacles.

    Abundance

    E. bellula occurs year round in the IRL. It is also collected from coastal stations (Walton Rocks) April - July.

    Locomotion

    Sessile

    Reproduction

    Reproductive season is unknown in this species.

  4. PHYSICAL TOLERANCES

    Temperature

    As a species that occurs year round, E. bellula can be considered a eurythermal species, as it must withstand seasonal fluctuations in water temperature.

    Salinity

    E. bellula is typically collected from Indian River Lagoon sites where salinity measures below 30‰.

  5. COMMUNITY ECOLOGY

    Trophic Mode

    E. bellula, like all bryozoans, is a suspension feeder. Each individual zooid in a colony has 10 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.

    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). E. bellula is generally found in association with Syringodium spp., however, it has also been collected coastally from April to July attached to brown algae (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
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Page last updated: July 25, 2001

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