Benthic Cnidaria community in the oceanic archipelago of Trindade and Martin Vaz, Southwestern Atlantic Ocean

Based on literature review, recent surveys, and specimens’ identification, we examined benthic cnidarian species richness across the oceanic Trindade and Martin Vaz Archipelago (TMA), Southwestern Atlantic Ocean. A total of 37 species (three Hydrozoa and 34 Anthozoa) are reported, including seven new records. The zooxanthellate scleractinian corals Montastraea cavernosa, Mussismilia hispida, Mussismilia leptophylla and Siderastrea stellata were the most commonly found species, while some species, such as the azooxanthellate coral Polycyahtus sp., were only found at one site. Although Martin Vaz Island has a lower diversity (11 species) compared to Trindade Island (37 species), fewer studies have been conducted in the former. Likewise, research in the TMA has focused on shallow water communities (<40 m depth), and comprehensive surveys of benthic Cnidaria species of mesophotic and deeper water habitats are needed. All data presented herein are discussed in the light of species ecology and distributional patterns and we also report tissue necrosis in some Octocorallia colonies.