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Species Name:    Thalamoporella floridana
Common Name:                           (None)



Kingdom Phylum/Division: Class: Order: Family: Genus:
Animalia Ectoprocta Gymnolaemata Cheilostomata Thalamoporellidae Thalamoporella

SEM of Thalamoporella floridana showing individual zooids. Photo by J. Winston, courtesy of the American Museum of Natural History. Used with permission.

Species Name:
Thalamoporella floridana Osburn, 1940

Voucher Specimen: 
American Museum of Natural History 
# 595

Common Name:


Species Description:
T. floridana is an encrusting species whose colonies sometimes rise into erect rosettes or frills (Winston 1982). Colonies are gray to white in color, with individual zooids quadrangular in shape and of variable size. Typical zooid size is 0.45 - 0.50 mm in height, and 0.20 - 0.25 mm in width. Distinct grooves separate individuals. The frontal membrane covering the colony surface is lightly calcified but perforated, except at the distal opesia and 2 large opesiules proximal to it (Winston 1982). One of the opesiules is generally larger than the other, and is bounded by a descending tubular portion of the cryptocyst continuing to the basal wall of the zooid (Winston 1982). The opesia themselves are hoof-shaped. Avicularia between zooids are arch-shaped, with the point of the mandible bent. Spicules occur in the body cavity and resemble calipers. Polypides collected in the winter months had large, bulbous intertentacular organs (Winston 1982).


Other Taxonomic Groupings:
Suborder: Anasca

Potentially Misidentified Species:
Osburn (1940) first described T. floridana as a subspecies of T. gothica. However, T. gothica had originally been described from the Pacific Ocean around Mexico. T. gothica specimens from the Pacific have large ovicells that may brood several embryos at once. They also have spicules in the shape of open compasses, and wider opesiae with no adoral tubercles (Winston 1982). Conversely, Atlantic coast specimens of T. floridana have not been described with ovicells; their spicules are caliper shaped, and they possess adoral tubercles.


Regional Occurrence:
T. floridana occurs from Cape Hatteras south to Florida, the Gulf of Mexico and the Caribbean.

IRL Distribution:
T. floridana occurs year-round at coastal locations and within the IRL (Winston 1982).


Age, Size, Lifespan:
Zooids are variable in size and range from 0.45 - 0.50 mm in height, 0.20 - 0.25 mm in width.

T. floridana can be collected year-round in Florida, but is most abundant in the winter months. It was reported by Winston to be the most abundant bryozoan encrusting stems of the hydroid Thyroscuphus ramosus in winter. Colonies are least abundant in the summer.


No ovicells are present in T. floridana.


As a species which occurs year-round, and in greater abundance throughout the winter months, T. floridana is considered to be eurythermal.

T. floridana is typically collected from areas where salinity exceeds 30‰ (Winston 1982).


Trophic Mode:
T. floridana, 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 could clear 8.8 ml of water per day.

Typical habitat for ectoprocts in the Indian River Lagoon include seagrasses, drift algae, oyster reef, docks, pilings, breakwaters, and man-made debris (Winston 1995). T. floridana is the most abundant species on the stems of the hydroid Thyroscyphus ramosus during the winter. It was also found encrusting rhodophytes at coastal locations and attached to breakwater rocks at Sebastian Inlet, where it forms large masses in January (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 supporting substrata: mangrove roots, oyster beds, mussels, etc.


Special Status:

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.

Economic Importance:


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