Actiniaria

Sea anemones (order Actiniaria) are among the most diverse and successful members of the anthozoan subclass Hexacorallia, occupying benthic marine habitats across all depths and latitudes. Actiniaria comprises approximately 1,200 species of solitary and skeleton-less polyps and lacks any anatomical synapomorphy. Although monophyly is anticipated based on higher-level molecular phylogenies of Cnidaria, to date, monophyly has not been explicitly tested and at least some hypotheses on the diversification of Hexacorallia have suggested that actiniarians are para-or poly-phyletic. Published phylogenies have demonstrated the inadequacy of existing morphological-based classifications within Actiniaria. Superfamilial groups and most families and genera that have been rigorously studied are not monophyletic, indicating conflict with the current hierarchical classification. We test the monophyly of Actiniaria using two nuclear and three mitochondrial genes with multiple analytical methods. These analyses are the first to include representatives of all three currently-recognized suborders within Actiniaria. We do not recover Actiniaria as a monophyletic clade: the deep-sea anemone Boloceroides daphneae, previously included within the infraorder Boloceroidaria, is resolved outside of Actiniaria in several of the analyses. We erect a new genus and family for B. daphneae, and rank this taxon incerti ordinis. Based on our comprehensive phylogeny, we propose a new formal higher-level classification for Actiniaria composed of only two suborders, Anenthemonae and Enthemonae. Suborder Anenthemonae includes actiniarians with a unique arrangement of mesenteries (members of Edwardsiidae and former suborder Endocoelantheae). Suborder Enthemonae includes actiniarians with the typical arrangement of mesenteries for actiniarians (members of former suborders Protantheae, Ptychodacteae, and Nynantheae and subgroups therein). We also erect subgroups within these two newly-erected suborders. Although some relationships among these newly-defined groups are still ambiguous, morphological and molecular results are consistent enough to proceed with a new higher-level classification and to discuss the putative functional and evolutionary significance of several morphological attributes within Actiniaria.

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.

temperate waters; shallow water. South Chilean fjords contain an astonishing diverse benthic macrofauna of which anthozoans form a major portion. Azooxanthellate solitary scleractinians, which were hitherto known from major depths, were found as shallow as 8 m during several expeditions to the south Chilean fjord region. At some sites, stony corals dominate the macrofauna and form dense aggregations, which may cover several 10's of square meters in depths below 25 m. The discovery of these communities in shallow water for the first time allows for in situ observations and structural analysis of these populations by means of SCUBA diving. For further studies, living and dead corals were sampled, photographed, and dried for preservation. Several specimens and tissue samples were preserved in 96% ethanol. The sampled specimens were identified as Desmophyllum dianthus (Esper, 1794) and Caryophyllia Lamarck, 1801 spec. nov. Specimens of D. dianthus found on a shipwreck allowed for growth rate estimations. Minimum growth rates were estimated as 2.3 mm longitudinal growth per year and 1.6 mm diameter growth. Due to increasing human impact on benthic communities in Chilean fjords, especially through salmon farming, it cannot be excluded that these coral communities are in danger before they are even studied.