Their similar colony morphologies misled scientists to historically lump them into a single species, Montastraea annularis, which included three morphotypes “bumpy”, “columnar” and “massive”.

These growth forms were believed to arise as a response to abiotic factors (e.g., depth, light availability).

This taxonomic classification was challenged by further ecological, reproductive, genetic, and morphologic evidence, which led to the re-description of three separate species, Montastraea faveolata (massive), M. annularis (columnar) and M. franksi (bumpy).

The colonies of these corals are massive and form dome-shaped mounds, with uneven surfaces and bulging projections.

Speciation can be studied from many perspectives, but regardless of the point of view it often requires reproductive isolation between species.

In the case of the Orbicella, these species are broadcast spawner corals and release gametes annually in the same evening into the water column.