Other Taxonomic Groupings
Colonies of A. leucocypha
are encrusting in single or multiple layers, and are typically a whitish to
pink or magenta color. Individual zooids are variable in shape, but are
generally oval, narrowing toward the distal portion. In secondary layers,
zooids may often be irregularly oriented. Zooids measure approximately 0.33
X 0.23 mm. Opesia of zooids are wider proximally, narrowing distally.
Triangular spaces between typical feeding individuals (autozooids) are often filled with smaller kenozooids, calcareous deposits, solid tubercles, or tubercles that are
transformed into avicularia. However, in older colonies, kenozooids and
avicularia may be absent from large areas of the colony. Polypides are
transparent to white in color. The lophophore measures an average of 0.326
mm in diameter, and bears an average of 12 tentacles.
Potentially Misidentified Species
A. leucocypha is quite similar to A. tincta. Cook (1968) differentiated these species
based on differences in the frequency of occurrence in kenozooids, the size of
the avicularia, and on the shape of their mandibles. Winston (1982) observed
that in Florida specimens of these species smaller, unilaminar colonies, which were presumed to be younger colonies, generally resembled the
description for A. leucocypha. Conversely, large, multilaminar
(multi-layered) colonies approached the description for A. tincta.
Winston (1982) also reported differences in the texture of the cryptocysts that aided in identification.
HABITAT AND DISTRIBUTION
A. leucocypha occurs in warm waters of both the Atlantic and Pacific Oceans. In the Western
Atlantic, it occurs most commonly from Cape Hatteras to Florida, the Gulf of
Mexico and the Caribbean.
A. leucocypha is collected year round in the IRL and at coastal locations. It is most common intertidally along the coast.
LIFE HISTORY AND POPULATION BIOLOGY
Age, Size, Lifespan
Zooids measure 0.30 - 0.35 mm in height by 0.20 - 0.25 mm in width. The lophophore measures approximately 0.326
mm in diameter and bears an average of 12 tentacles.
A. leucocypha is common intertidally along the coast of Florida, and can be found year round
within the IRL in areas where salinity is above 30ï¿½ (Winston
Endozooidal Ovicells are present in A. leucocypha. Opercula of both fertile and sterile
zooids are highly variable, thus fertile zooids are sometimes difficult to
detect (Winston 1982).
Because it can be collected in the
IRL year round, A. leucocypha is considered to be eurythermal.
is typically collected in areas of the IRL where salinity exceeds 30‰ (Winston
A. leucocypha, like all bryozoans, is a suspension feeder. Each individual zooid in a colony
has an average of 12 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.
Typical habitat for ectoprocts in
the Indian River Lagoon include seagrasses, drift algae, oyster reef, dock,
pilings, breakwaters, and man-made debris (Winston 1995). A. leucocypha
typically encrusts gastropod shells. Unilaminar colonies are generally found on
living gastropods, while multilaminar colonies are often found on dead gastropod
shells inhabited by hermit crabs.
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,
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.
Cook PL. 1968. Observations on living Bryozoa. Atti Soc Ital Sci Nat Mus Civ Stor Nat Milano 108: 155-160.
Winston JE. 1982. Marine bryozoans (Ectoprocta) of the Indian River area (Florida). Bull Amer Mus Nat Hist 173: 99-176.
Winston JE. 1995. Ectoproct diversity of the Indian River coastal lagoon. Bull Mar Sci 57: 84-93.