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Species Name:    Victorella pavida
Common Name:                  (None)

 

I.  TAXONOMY

Kingdom Phylum/Division: Class: Order: Family: Genus:
Animalia Ectoprocta Gymnolaemata Ctenostomata Victorellidae Victorella


Growth pattern of Victorella pavida showing stolon arising from zooid bases.  Drawing by J. Winston, courtesy of American Museum of Natural History.  Used with permission.
Species Name:
Victorella pavida Saville Kent, 1870

Common Name:
None.

 

 

 


Species Description:
Colonies of V. pavida develop as chains of zooids connected by the stolon that arises from the base of new zooids. In young colonies, overall morphology of the colony is quite simple; however, as they develop, zooids elongate and bud off new stolons and zooids to form extensive networks. Individual zooids are cylindrical and measure approximately 0.15 X 0.60 mm. In older colonies, zooids can measure as much as 2 - 3 mm (Winston 1982). The lophophore averages 0.37 mm in diameter and bears 8 tentacles.

Synonymy:
None

Other Taxonomic Groupings:
Suborder: Carnosa
Superfamily: Paludicelloidea

Potentially Misidentified Species:
Colonies of V. pavida resemble those of the genus Bowerbankia. These groups are differentiated based on differences in growth from the stolon. In Bowerbankia, new zooids are budded separately from the stolon; in Victorella pavida, the stolon arises from the base of zooids.


II.  HABITAT AND DISTRIBUTION 
Regional Occurrence
:
V. pavida is a cosmopolitan species whose range in the western Atlantic extends from Chesapeake Bay to Brazil.

IRL Distribution:
Prior to Winston's (1982) study, this species had not been documented in the IRL. During the study, it was collected only once, at Link Port, approximately 7 miles north of Ft. Pierce Inlet, but it is likely to be distributed in brackish areas throughout the IRL (Winston 1982).


III.  LIFE HISTORY AND POPULATION BIOLOGY
Age, Size, Lifespan:
Individual zooids measure 0.15 X 0.60 mm on average, but can be 2 - 3 mm in older colonies. The lophophore measures approximately 0.37 mm in diameter.

Abundance:
While this species can be locally abundant throughout its range, it is considered rare in the Indian River Lagoon. Winston (1995) reported it as a fouling organism in the IRL.

Locomotion:
Sessile

Reproduction:
The reproductive period of this species is not well described.

Embryology:
V. pavida is a member of the Order Ctenostomata that broods its embryos.


IV.  PHYSICAL TOLERANCES
Salinity:
Of the 36 known bryozoans in the Indian River Lagoon, V. pavida is one of only 3 brackish water bryozoans. The other 33 are collected from waters where salinity generally exceeds 30 (Winston 1982).


V.  COMMUNITY ECOLOGY
Trophic Mode:
V. pavida, like all bryozoans, is a suspension feeder. Each individual zooid in a colony has 8 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.

Habitats:
In the IRL, V. pavida was collected only from seagrass beds around Link Port.

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.


VI.  SPECIAL STATUS
Special Status:
None.

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:
None.

 

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