Diversity Patterns of Modern Arctic and Antarctic Bryozoans

A comparison of Arctic Sea and Antarctic Sea bryozoan faunas (cheilostomes) was conducted by compiling comprehensive data sets from both realms [1, 2] and own additional collections from the European Sector of the Arctic Realm. The analysis documents the high endemism in Antarctic faunas also indicated by the high species/genera relationship compared to the extremely reduced endemism in the Arctic Realm. These different patterns are explained by the long-lasting geographic isolation of the Antarctic continent due to tectonic break-up of the Gondwana continent in contrast to the Arctic Ocean, which since the Neogene became a transit system to promote migration of bryozoan species between the North Atlantic and North Pacific oceans. Cluster analysis was applied to identify the biogeographic regions within the two polar realms.International Symposium, "The Origin and Evolution of Natural Diversity". 1–5 October 2007. Sapporo, Japan