Boulder star coral
''Orbicella annularis'', commonly known as the boulder star coral, is a species of coral that lives in the western Atlantic Ocean and is the most thoroughly studied and most abundant species of reef-building coral in the Caribbean to date. It also has a comprehensive fossil record within the Caribbean. This species complex has long been considered a generalist that exists at depths between 0 and 80 meters that grew into varying colony shapes in response to differing light conditions. Only recently with the help of molecular techniques has ''O. annularis'' been shown to be a complex of at least three separate species. Those species are divided into ''O. annularis'', ''O. faveolata'', and ''O. franksi''. This coral used to be known as ''Montastraea annularis''.