Pectinatella magnifica
Colony of Pectinatella magnifica.
Pectinatella magnifica, which is also known as sponge-like bryozoans, is a freshwater bryozoans, whose original habitat is in North America. It was introduced at an unknown time after Central Europe ( first record 1883) and is now also available in Japan and Korea.
Features
Pectinatella magnifica forms very large colonies, 30 inches long, 20 inches thick and weigh over a kilogram. Chance were reported to two meters even of colonies with diameters of one. From the outer appearance, her these colonies are similar to sponges, but are not related to this group of animals.
The colonies float freely in the water or can be grown on a solid substrate. They are gelatinous and slimy. Its interior consists of 99 % water. The colony surface consists of individual rosettes, which themselves consist of 12 to 18 individual animals ( zooids ). Each individual animal is tiny and filters with a wreath of 60 to 80 tentacles plankton tables organisms from the water. Pectinatella magnifica occurs mainly in stagnant waters, optimal temperatures are above 20 ° C. Scattered reports of the occurrence of Bryozoans in rivers are. In case of unfavorable living conditions resting stages ( Statoblasten ) are formed. They are spherical, with a diameter of one millimeter and adhered 10 to 12 hooks to the substrate.
Parasites
For the kind belonging to the microsporidia parasites are known as Trichonosema pectinatellae and Trichonosema algonquinensis. They cause white spherical growths in tissues of bryozoans.
Introduction to Europe
The species is due to their distribution pattern (occurrence, especially in ports and along shipping routes ) and the fact that it spreads they also currently further (since 1990 example after France and the Czech Republic ) as new immigrants ( neozoon ) in Europe. The actual introduction, however, is not documented and has also been questioned