Species Description: Sundanella sibogae is an encrusting bryozoan whose colonies form tiny encrustations on algae, seagrasses such as Syringodium, and the roots of hydroids. Zooids are arranged uniserially, with each polypide functioning somewhat independently of its neighbors. Individual zooids are large, oval or teardrop in shape, and their growth pattern tends to obscure the stolon.
Zooids measure approximately 0.50 X 1.45 mm and are generally yellow to brown in color. The lophophore measures an average of 0.820 mm in diameter, and bears 31 tentacles, thus making it one of the larger species of bryozoans studied.
Other Taxonomic Groupings: Suborder: Carnosa
Regional Occurrence: In the western Atlantic, S. sibogae occurs from Beaufort, South Carolina, and south through Florida and the Gulf of Mexico to Brazil.
IRL Distribution: S. sibogae has been collected from Haulover Canal, Titusville and also at sites along the coast.
Age, Size, Lifespan: Zooids measure 0.5 X 1.45 mm. The lophophore has 31 tentacles and measures approximately 0.82 mm in diameter.
Abundance: S. sibogae is likely to occur year-round in the Indian River Lagoon, but is not considered abundant.
Reproduction: Reproductive season in this species is not known (Winston 1982).
Embryology: The embryology of S. sibogae is unknown.
Temperature: Because S. sibogae is likely to occur year-round in the IRL, it is considered eurythermal.
Salinity: S. sibogae is collected coastally and within the Indian River Lagoon where salinity exceeds 30‰ (Winston 1982).
Trophic Mode: S. sibogae, like all bryozoans, is a suspension feeder. Each individual zooid in a colony has 31 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 could clear 8.8 ml of water per day.
While actively feeding, the entire introvert, as well as the superior portion of the flexible zooecium of S. sibogae, scan back and forth constantly. This species also feeds by tentacle flicking, in which each tentacle is slowly bent in to approximately its length, then slowly bent back out. By using tentacle flicking in conjunction with ciliary action, this species is able to concentrate particles into a bolus that is then directed towards the mouth. The food bolus is maneuvered around the mouth, and the polypide eventually retracts into the zooid, taking the bolus with it.
Habitats: Typical habitat for ectoprocts in the Indian River Lagoon include seagrasses, drift algae, oyster reef, dock, pilings, breakwaters, and human-made debris (Winston 1995). S. sibogae is typically found as tiny encrustations on Syringodium and other seagrasses, algae, and the roots of hydroids.
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 m² of seagrass bed could potentially filter and recirculate an average of 48,000 gallons of seawater per day.