Acropora cervicornis (Lamarck, 1816)
Tentacles occur in multiples of 6, as is true for all stony corals (S.D. Cairns, in litt. December 2009).
Acropora cervicornis occurs only in the western Atlantic (one of three Acropora species found in the Atlantic). However, some of the ~120 Acropora species in the Pacific may also sometimes be referred to as "staghorn coral", leaving the incorrect impression that A. cervicornis occurs in the Pacific as well (S.D. Cairns, in litt. December 2009).