Species Description:
S. aegyptiacum
forms erect, branching and stolonate colonies that resemble strings of glass
beads. Zooids are scoop-shaped and occur in pairs, back to back along branches,
with joints between each pair. Zooids have large frontal areas that
are lightly calcified, and measure approximately 0.24 X 0.10 mm on average. Two
types of avicularia are present: box-shaped, sessile avicularia located in the
distal corners of zooids, and bulbous pedunculate avicularia located on the
dorsal surface. Radicles used for attachment to the substratum may have
elaborate hook-like ends. The lophophore averages 0.231 mm in diameter and bears
10 tentacles.
Synonymy:
Loricaria aegyptica
Audouin, 1826
Synnotum aviculare Osburn, 1914
Other Taxonomic Groupings:
Suborder: Anasca
II. HABITAT AND
DISTRIBUTION
Regional Occurrence:
S. aegyptiacum
is highly cosmopolitan in warm waters. In the
western Atlantic, this species is distributed from Cape Hatteras south to
Florida, the Gulf of Mexico, the Caribbean and Brazil.
IRL Distribution:
S. aegyptiacum
occurs year-round at coastal stations and within the IRL, though IRL colonies
may sometimes overwinter in a dormant state.
III. LIFE HISTORY AND POPULATION BIOLOGY
Age, Size, Lifespan:
Individual zooids average 0.24 X 0.1 mm in size.
The lophophore measures an average of 0.231 mm in diameter and bears 10
tentacles.
Abundance:
S. aegyptiacum colonies
are large and abundant between October and December.
Locomotion:
Sessile
Reproduction:
Midsummer is the likely reproductive season for
this species, as zooids containing sperm were reported in July (Winston 1982).
No ovicells are present in this species.
Embryology:
Embryos are brooded inside gonozooids that become enlarged when embryos are present.
IV. PHYSICAL TOLERANCES
Temperature:
S. aegyptiacum
is considered to be a warm water species. It is collected year-round in the IRL,
but colonies may overwinter in a dormant state. Winston (1982) reported that
colonies collected in January from Sebastian Inlet contained only brown bodies
in distal zooids, and had granular, starchy material in proximal zooids.
Salinity:
S. aegyptiacum
is typically collected at locations where salinity exceeds 30‰.
V. COMMUNITY ECOLOGY
Trophic Mode:
S. aegyptiacum,
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 could 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). S. aegyptiacum is typically found
entangled among hydroid stems, primarily Thyroscyphus and Eudendrium species.
It has also been documented to colonize both benthic and floating algae, and may
utilize other substrata such as shell fragments and beach rock. It has also been
collected from depths of 10 m from Capron Shoals, Florida (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.
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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irl_webmaster@si.edu
Page last updated: July 25, 2001
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