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What are the three main classes of Bryozoa?
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moss animal
Eurystomella bilabiata, a moss animal from the Order Cheilostomata.
The phylum Bryozoa, commonly known as moss animals, is divided into three main classes based on their habitat and structural characteristics:12
- Phylactolaemata: These are exclusively freshwater-dwelling bryozoans. They are characterized by a crescent-shaped lophophore and the presence of an epistome, a hollow flap that overhangs the mouth.12
- Stenolaemata: This class is primarily marine and consists of organisms with cylindrical zooids and calcified body walls. While they have a long fossil record dating back to the Ordovician, only the order Cyclostomata remains represented by living species today.123
- Gymnolaemata: These are mostly marine bryozoans. Unlike the other classes, their lophophore is circular, and they lack an epistome. This class includes the highly successful order Cheilostomata.12