Zoogeography of Chilean marine and freshwater decapod crustaceans

Using more than 200 genera and 431 species that comprise the 77 families of decapod crustaceans inhabiting Chilean waters, we attempted to reveal the underlying zoogeographical pattern of these taxa by comparing areas in terms of the number of shared species, genera, and families. To this end, the coasts and oceanic islands were divided into sixteen areas, encompassing most of the Nazca plate including Easter Island, Salas and Gomez Island, the Desventuradas Islands, and Juan Fernandez Archipelago, as well as the underwater mountains of Salas & Gomez and Nazca (5 areas), the western coast of South America from Arica to Cape Horn (ca. 18 degrees S-56 degrees S; 10 areas), and the Antarctic peninsula and adjacent areas (1 area). The four resulting dendrograms coincided, showing six province: a) Chile-Peru (18 degrees-42 degrees S); b) Magellan (42 degrees-56 degrees S); c) Antarctica, including the Antarctic peninsula and the Scotia Arc archipelagos; d) Juan Fernandez Archipelago (33 degrees 40'S; 79 degrees 00'W), including the Desventuradas Islands (ca. 26 degrees 20'S, 80 degrees W); e) Easter Island (27 degrees 09'S, 109 degrees 25'S); and f) the underwater mountains of Salas & Gomez and Nazca (ca. 25 degrees S; ca. 75 degrees W-100 degrees W). The dendrogram based exclusively on families inhabiting these diverse geographic areas identified two large clusters: the first encompassing the oceanic areas over the Nazca plate and the second the continental (10) and Antarctic (1) areas. In addition, decapod crustacean species of the southern tip of South America extend from the southeastern waters of the Pacific Ocean on one side of the Strait of Magellan to the southwestern waters of the Atlantic Ocean, reaching the Kerguelen Islands at the boundary of the Indian and Antarctic ocean.