Biodiversity and distribution of sea anemones (Cnidaria, Anthozoa, Actiniaria) in Peru

Diverse and abundant sea anemones are common in shallow marine areas. Detailed biodiversity analysis in Peru are comparatively scarce. To contribute to the biodiversity inventory and distribution information of this taxa, we analyzed exhaustively the available bibliography in Peruvian waters. A total of 23 anemone species were identified, distributed in 68 localities, and grouped into 1 Order (Actiniaria), 6 Families (Actiniidae, Actinostolidae, Aiptasiidae, Isanthidae, Phelliidae and Sagartiidae) and 20 Genera. The most reported species are Anthothoe chilensis (37 references), Phymactis clematis (28), Phymanthea pluvia (27), Oulactis concinnata (18), and Antholoba achates (15). Lima is the region with the highest number of publications, followed by La Libertad, Piura, Lambayeque, and Ancash. Anthothoe chilensis occurs in almost all the Peruvian coastal regions. On the contrary, O. concinnata has been primarily observed in Lima, while A. achates occurred only in the southern regions (Ica, Arequipa, and Moquegua). Rocky substrates (~55% records) seem to be the most suitable habitat for sea anemones in Peru, corresponding to exposed (e.g. vertical walls) and sheltered zones (e.g. rocky crevices, caves, under rock areas). Although most of the species in Peru exhibit a relatively wide spatial distribution, our results suggest that there are several regions with little or no research efforts. Despite a growing study effort over the past 30 years (>50% of biodiversity reported), the current biodiversity status for this group is still unclear. A significant effort is needed to better analyze occurrence patterns and unveil new species regarding a changing environmental scenario with human influence.