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Ectoprocta

(Phylum)

Overview

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Formerly known as Bryozoa, these are a phylum of colonial coelomates which bear lophophores, and which live in horny, calcareous or gelatinous cases, commonly called moss animals.

The Ectoprocta were known as Bryozoa (moss animals) for a long time and also included another group of animals the Entoprocta. Of the 4000 species of ectoprocts , few are more than 0.5 mm long, all are aquatic, found both in marine and freshwater and most, with very few exceptions are colonial.

Each member of a colony lives in a chamber secreted by its epidermis, called a zoecium, and consists of a feeding polypide and a case-forming cystid. The polypide includes the lophophore, digestive tract, muscles and nerve centres; the cystid is the body wall of the animal together with its secreted exoskeleton . The exoskeleton varies according to the species and may be gelatinous, chitinous, stiffened with calcium or impregnated with sand.

Some colonies form encrustations on seaweed, shells and rocks; others form shrubby growths or erect colonies that look like seaweed. Some ectoprocts could be mistaken for hydroids but can be distinguished under a microscope by the fact that their tentacles are ciliated.

Photos

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Taxonomy

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The Phylum Ectoprocta is further organized into finer groupings including:

Classes

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Gymnolaemata

Gymnolaemata is a class of the phylum Bryozoa. Gymnolaemata typically live under seawater and grow on surfaces of rocks, kelps, and even in some cases, on animal species like fish. They are mostly marine bryozoans with cylindrical or flattened he lophophore is protruded by action of muscles pulling on frontal wall. This order includes the majority of living bryozoan species. [more]

At least 2,851 species and subspecies belong to the Class Gymnolaemata.

More info about the Class Gymnolaemata may be found here.

Sources

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Last Revised: October 03, 2013
2013/10/03 15:44:52