Abstract:
The Isopoda are a large and morphologically diverse group of crustaceans. Roughly 6,250 of the 10,300 described species are marine or estuarine. The taxonomic description of isopods started in 1840 and shows two strong phases of discovery and although the discovery rate has slowed down since the 1990s, the Isopoda are a promising group for more new species discoveries in the future. The order has a worldwide distribution occurring in terrestrial, freshwater, and marine habitats. Marine isopods can be found from pole to pole in each of the worlds’ oceans. The majority of the known species occurs in shallow-water habitats, but isopods are also widely distributed in the deep sea with the Asellota as the dominant group at these depths. Some isopod families have evolved a parasitic life-style, displaying different life histories and often a highly modified appearance. Those parasites do not only infest wild host populations, but also frequently cause problems in fish farming and commercial fisheries. As marine woodborers some species, too, cause considerable damage to man-made marine infrastructure.