Shallow-water scleractinian corals of Ascension Island, Central South Atlantic
Résumé
The presence of five shallow-water scleractinian species at Ascension Island is confirmed, i.e. Favia gravida, Madracis sp., Siderastrea radians, Polycyathus atlanticus and Rhizosmilia gerdae. The three former are zooxanthellate, the two latter azooxanthellate. A sixth species, Cladocora debilis (azooxanthellate), dredged from moderately deep water is also expected to occur in shallow water. Madracis sp. and P. atlanticus are new records for the island. A previous record of Astrangia solitaria at Ascension is now referred to as P. atlanticus. Favia gravida, S. radians and C. debilis are amphi-Atlantic. Rhizosmilia gerdae is currently known only from Ascension Island and the Western Atlantic. None of the species are endemic to Ascension Island. No member of the family Dendrophylliidae has as yet been found at Ascension, whereas that family is represented at its nearest neighbour, St Helena Island.