Bryozoan Species Stock Video Footage

Bryozoans, phoronids and brachiopods strain food out of the water by means of a lophophore, a "crown" of hollow tentacles. Bryozoans form colonies consisting of clones called zooids that are typically about 0.5 millimetres (0.020 in) long. Phoronids resemble bryozoan zooids but are 2 to 20 centimetres (0.79 to 7.87 in) long and, although they often grow in clumps, do not form colonies consisting of clones. Brachiopods, generally thought to be closely related to bryozoans and phoronids, are distinguished by having shells rather like those of bivalves. All three of these phyla have a coelom, an internal cavity lined by mesothelium. Some encrusting bryozoan colonies with mineralized exoskeletons look very like small corals. However, bryozoan colonies are founded by an ancestrula, which is round rather than shaped like a normal zooid of that species. On the other hand, the founding polyp of a coral has a shape like that of its daughter polyps, and coral zooids have no coelom or lophophore. Entoprocts, another phylum of filter-feeders, look rather like bryozoans but their lophophore-like feeding structure has solid tentacles, their anus lies inside rather than outside the base of the "crown" and they have no coelom. All bryozoans are colonial except for one genus, Monobryozoon. Individual members of a bryozoan colony are about 0.5 millimetres (0.020 in) long and are known as zooids, since they are not fully independent animals. All colonies cont... Learn more about Bryozoan