Bryozoan Statoblast (diminutive aquatic animal of the phylum Bryozoa)
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Chiedozie Ukachukwu
Student at the Rochester Institute of Technology
Rochester, New York, USA
BRYOZOANS
Moss Animals
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Description.
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Although inconspicuous and poorly known to most people, bryozoans are a major animal groups, having nearly 4,000 known species. Most bryozoans are marine, but a few dozen species live in freshwater habitats and a number these are known in South Dakota. They take the name Bryozoa (Latin for "moss animals") from their colonial and often 'furry' growth habit. Most colonies have a gelatinous matrix and form encrusting growths or branching colonies. They may grow on any submerged object, such as rocks, roots, and branches.
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The individual animals of a bryozoan colony are tiny, typically only 2 to 3 millimeters in length. Their most conspicuous feature is a retractable crown of hollow, ciliated tentacles, called the lophophore. T he lophophore serves in filter-feeding. Bryozoans feed on protozoans, bacteria, and organic matter from the water. In the center of the lophophore is the mouth, which marks the beginning of a U-shaped gut. The anus opens just outside the lophophore. The Bryozoa are sometimes classified as the Ectoprocta ('outer anus') to emphasize this feature.
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Bryozoan taxonomy is complex and depends largely on microscopic details. Identification is made easier because most freshwater species produce resistant bodies called statoblasts. These form in response to adverse environmental conditions. They contain a mass of cells enclosed in a bi-valved, hardened shell
