Species Description:
Living colonies are distinguished by their
uniserial, jointed branches, and their brick red to brownish color that results
from coloration in the polypides, or from the presence of embryos within zooids.
Individual zooids are somewhat trumpet shaped, with an inflated distal portion
having pores that penetrate the frontal surface, and tube-like proximal portion.
Zooids measure approximately 0.75 - 1.5 mm in length. The orifice is
semicircular in shape and is surrounded by a raised peristome with 4 spines.
Suborally, there is a large, pointed avicularium with a triangular mandible. The
lophophore bears 17 - 19 tentacles (Marcus 1937, Winston 1982).
Synonymy:
Savignyella lafontiii:
Osburn 1914
Other Taxonomic Groupings:
Suborder: Ascophora
II. HABITAT AND
DISTRIBUTION
Regional Occurrence:
S. lafontii
is
highly cosmopolitan in warm waters. In the western Atlantic, its
range extends from Bermuda to the east coast of Florida, and south through the
Gulf of Mexico, the Caribbean, and Brazil.
IRL Distribution:
S. lafontii
is
found at coastal stations all along the Indian River Lagoon. Within the IRL, it
has been collected at the Sebastian Inlet grass flats, and is likely to be found
at other IRL locations.
III. LIFE HISTORY AND POPULATION BIOLOGY
Age, Size, Lifespan:
Individual polypides of S. lafontii reach
0.75 - 1.5 mm in length. The lophophore bears 17 - 19 tentacles.
Abundance:
The delicate branches of S. lafontii colonies
are often not obvious until the substratum is examined microscopically. S. lafontii
occurs year-round in Florida, but is most common from September -
December. Winston (1982) reported this species to be especially abundant near
Ft. Pierce Inlet.
Locomotion:
Sessile
Reproduction:
Ovicells are globular in shape and perforated by
small pores. In Florida, reproduction may occur year-round.
IV. PHYSICAL TOLERANCES
Temperature:
S. lafontii occurs year-round in Florida, and is thus considered eurythermal.
Salinity:
S. lafontii was
most common at coastal locations. Within the IRL, it was generally collected in
areas where salinity remained above 30 ‰.
V. COMMUNITY ECOLOGY
Trophic Mode:
S. lafontii,
like all bryozoans, is a suspension feeder. Each individual zooid in a colony
has 17 - 19 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). S. lafontii occurred on the roots of
hydroids, most commonly on those of Thyroscyphus. It was also found
intermingling with Vittaticella among hydroid roots. Winston (1982)
reported S. lafontii to also occur on algae, sponges and on other
bryozoans such as Zoobotryon.
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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