Acropora palmata (Lamarck, 1816) - elkhorn coral on a reef.

Stony corals have a patchy distribution in the shallow marine waters surrounding San Salvador Island. They occur as isolated individual colonies, in patch reefs, fringing reefs, and barrier reefs. Stony corals are scleractinian anthozoan cnidarians (there are also non-scleractinian stony corals in the fossil record, such as tabulates and rugosans). They consist of individuals or colonies of gelatinous polyps that secrete hard skeletons of aragonite (CaCO3). Most scleractinian corals live in warm, tropical to subtropical, photic zone environments (the shallow portions of the world’s oceans where sunlight penetrates). Microbes (Symbiodinium - Protista, Dinoflagellata/Pyrrhophyta) called zooxanthellae live in their tissues and need to be in sunlight to make their own food (photosynthesis), which is shared with the host coral animal. Scleractinian corals have stinging cells (nematocysts) in their tentacles that paralyze prey.

The brownish and grayish branching organisms below the elkhorn corals are octocorals. The upright bladed organisms are Millepora complanata - bladed fire corals.

Classification: Animalia, Cnidaria, Anthozoa, Scleractinia, Acroporidae