Species Description:
Living colonies are pink, beige or white in
color. C. pallasiana is an encrusting type whose colonies sometimes rise
into frills. Zooids are hexagonal in shape and measure approximately
0.6 X 0.4 mm in size. The frontal surface is heavily calcified and has large
pores set into it. Colonies may sometimes appear to have a beaded surface due to
zooids having a suboral umbo. The orifice is bell-shaped and large, with a deep,
rounded anterior portion, and a shallow arc posteriorly. The peristome is narrow
and frames the orifice. Occasionally, small, sub-oral avicularia are detected,
though none were observed in Winston's (1982) specimens of this species.
Synonymy:
None
Other Taxonomic Groupings:
Suborder: Ascophora
II. HABITAT AND
DISTRIBUTION
Regional Occurrence:
C. pallasiana
is cosmopolitan, with worldwide distribution, but its range is sometimes
disjunct. Marcus (1942) suggested its distribution could be related to its
proximity to shipping lanes.
IRL Distribution:
C. pallasiana
is a common fouling organism that is most common from Spring through Fall in the
IRL (Winston 1995).
III. LIFE HISTORY AND POPULATION BIOLOGY
Age, Size, Lifespan:
Individual zooids measure approximately 0.6 X 0.4
mm in size.
Abundance:
C. pallasiana is
a cosmopolitan and common fouling species in the IRL.
Locomotion:
Sessile
Embryology:
No ovicells are present in this species. Rather,
embryos are brooded in ovisacs within individual zooids. The presence of embryos
is detected due to their orange color, and was only recorded in April.
IV. PHYSICAL TOLERANCES
Temperature:
C. pallasiana
occurs most commonly between April and December, with colonies active at all
times during this period.
Salinity:
C. pallasiana
is tolerant of reduced salinities.
V. COMMUNITY ECOLOGY
Trophic Mode:
A. sica, like all bryozoans, is a suspension feeder. Each individual zooid in a colony has ciliated tentacles that are
extended to filter phytoplankton less than 0.045 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). C. pallasiana occurred on nearly any
hard substratum including rock, glass, and beach rocks.
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.
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
Submit additional information, photos or comments to:
irl_webmaster@si.edu
Page last updated: July 25, 2001
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