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Abstract SYSTEMATICS AND BIOLOGY OF ANTARCTIC BRYOZOANS Judith E. Winston Antarctic bryozoans are spectacular. They are often larger and more colorful than their temperate relatives. A bottom trawl taken in 100 meters off the Antarctic Peninsula might come up stuffed with orange, yellow and tan bryozoan colonies. On the sea floor those colonies provided habitat and foraging grounds for fish and invertebrates. Antarctic bryozoans are also outstanding in their diversity. Well over 300 species have been described and new descriptions continue to appear. In the USARP collections we have identified 222 species, mostly belonging to the Cheilostomatida, the dominant order in Recent seas. Much about their ecology can be learned from study of the abundant material preserved in the USARP collections. Yearly growth bands demonstrate that colonies may live for decades and that growth rates are very close to those of related temperate species. The presence of embryos in the brood chambers of many species allows determination of seasonality of reproduction and fecundity of colonies of different sizes. A large proportion of Antarctic bryozoan species (81% for cheilostomes) are endemic. Endemic groups include bizarre and unusual forms in which polymorphism, the occurrence of individuals specialized to perform different tasks, is highly developed. Behavioral studies carried out with living colonies in the Antarctic have shown how different polymorphs function in cleaning and protecting colonies from trespassers or predators: capturing motile animals such as amphipods, polychaetes, and nematodes, and sweeping colonies free of debris.
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