Distribution patterns of Chilean shallow-water sea anemones (Cnidaria: Anthozoa: Actiniaria, Corallimorpharia); with a discussion of the taxonomic and zoogeographic relationships between the actinofauna of the South East Pacific, the South West Atlantic and the Antarctic

The first complete zoogeographical analysis of Chilean shallow water sea anemones (Actiniaria and Corallimorpharia) and their taxonomic relations with neighbouring faunas is provided, based on extensive recent sampling in combination with a literature review. Between 1994 and 2004, we collected more than 1000 specimens of 32 distinct species of Actiniaria and Corallimorpharia at more than 100 sites along the Chilean coast between Arica (18°30’S; 70°19’W) and the Straits of Magellan (53°36’S 70°56’W). Sampling was done in the intertidal during low tides and in the subtidal by means of SCUBA diving down to depths of 40 m. The northern part of the Chilean fjord region showed the highest number of species (23). Our results contradict an abrupt general change in the marine faunal composition at 42°S, instead showing the continuation of species of the exposed coast and the joining of fjord species due to the availability of additional habitats in the richly structured fjord region south of 42°S, and also to eurybathy. The southern distribution limits of the species we found in northern and central Chile show only one significant concentration around the Peninsula Taitao (approx. 48°S). This either indicates a zoogeographic barrier for shallow water species at the Peninsula Taitao, or is a sampling artifact caused by poor data from the region between the Peninsula Taitao and the Straits of Magellan. According to the literature, 18 of the 63 described Chilean sea anemones (Pacific Ocean) can also be found in Argentina (Atlantic Ocean) and 13 in the Antarctic. However, many records and statuses of the common species of the South East Pacific and the South West Atlantic/Antarctic are uncertain or doubtful and need revision or confirmation.

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