bryozoa
Bryozoa (also known as the Polyzoa, Ectoprocta or commonly as moss animals) are a phylum of simple, aquatic invertebrate animals, nearly all living in sedentary colonies. Typically about long, they have a special feeding structure called a ...
n belonging to the family Bugulidae, commonly known as the feather bryozoan. It is native to the Atlantic Ocean.
Description
''Crisularia plumosa'' is a colonial bryozoan that forms small bushy clumps, up to high, which are attached to the substrate by a tangled ball of
rhizoid
Rhizoids are protuberances that extend from the lower epidermal cells of bryophytes and algae. They are similar in structure and function to the root hairs of vascular land plants. Similar structures are formed by some fungi. Rhizoids may be uni ...
s. The founding zooid is circular and spineless. As it buds and develops into a colony, a robust central trunk is formed, and branches grow out dichotomously from this in a characteristic spiral fashion, each with fine feathery branchlets. The colony is whitish, or pale tan. The individual zooids are microscopic, about and form two calcified rows on each branchlet; some of the smallest zooids are
avicularia
''Avicularia'' is a genus of the family Theraphosidae containing various species of arboreal tarantulas. The genus is native to Panama, the Caribbean and tropical South America. Each species in the genus has very distinguishable pink foot pads. ...
, each able to use its mandible and hooked beak to catch
prey
Predation is a biological interaction where one organism, the predator, kills and eats another organism, its prey. It is one of a family of common feeding behaviours that includes parasitism and micropredation (which usually do not kill ...
, which is then passed to the somewhat larger neighbouring autozooids.
Distribution and habitat
''Crisularia plumosa'' is native to the northeastern Atlantic Ocean, its range extending from the
North Sea
The North Sea lies between Great Britain, Norway, Denmark, Germany, the Netherlands and Belgium. An epeiric sea, epeiric sea on the European continental shelf, it connects to the Atlantic Ocean through the English Channel in the south and the ...
and the coasts of the British Isles and Ireland, to the Iberian peninsula and Madeira; it is found sparingly in the
Mediterranean Sea
The Mediterranean Sea is a sea connected to the Atlantic Ocean, surrounded by the Mediterranean Basin and almost completely enclosed by land: on the north by Western and Southern Europe and Anatolia, on the south by North Africa, and on the ...
. It grows on rocky coasts with limited water movement, and on piers and jetties, and tolerates high levels of sediment in the water. It occurs at depths down to about .
Ecology
''Crisularia plumosa'' is a filter feeder; the tentacles on the
lophophore
The lophophore () is a characteristic feeding organ possessed by four major groups of animals: the Brachiopoda, Bryozoa, Hyolitha, and Phoronida, which collectively constitute the protostome group Lophophorata.diatoms, bacteria and other small organic particles within reach, and these are conveyed to the mouth. This species is a
protandrous hermaphrodite
Sequential hermaphroditism (called dichogamy in botany) is a type of hermaphroditism that occurs in many fish, gastropods, and plants. Sequential hermaphroditism occurs when the individual changes its sex at some point in its life. In particular, ...
and colonies have both male and female zooids; each individual zooid starts its existence as a male and later becomes a female. Sperm, liberated into the
water column
A water column is a conceptual column of water from the surface of a sea, river or lake to the bottom sediment.Munson, B.H., Axler, R., Hagley C., Host G., Merrick G., Richards C. (2004).Glossary. ''Water on the Web''. University of Minnesota-D ...
by male zooids, is drawn into female zooids where fertilisation takes place; the embryos are retained in a brood chamber. The
larva
A larva (; plural larvae ) is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle.
...
e have a short
plankton
Plankton are the diverse collection of organisms found in water (or air) that are unable to propel themselves against a current (or wind). The individual organisms constituting plankton are called plankters. In the ocean, they provide a crucia ...
ic phase before settling on the substrate and undergoing metamorphosis. Other animals, such as small sea spiders, sometimes take shelter among the branchlets of the clumps. Alongside ''
Flustra foliacea
''Flustra foliacea'' is a species of bryozoans found in the northern Atlantic Ocean. It is a colonial animal that is frequently mistaken for a seaweed. Colonies begin as encrusting mats, and only produce loose fronds after their first year of g ...
'', this species forms part of a dense bryozoan "turf" that is found on heavily silted but moderately wave-exposed rocks and boulders round certain coasts of Britain just below the littoral zone; the habitat is dominated by sponges '' Suberites ficus'', '' Suberites carnosus'' and '' Hymeniacidon perleve''.