Scolymia, commonly called scoly coral, is a genus of large-polyp stony corals (Scleractinia). These animals are believed date back to the Miocene with three extant species present in the eastern Atlantic Ocean.[1][2]
Unlike most other Scleractinia, Scolymia are solitary corals. Polyps can grow up to 10 cm in diameter. Morphology is diverse with both interspecific and intraspecific variation in shape.[3] Polyps may be concave, convex, or flat depending on the species and environmental conditions. Species are generally distinguished based on differences in septa number, thickness, and orientation.[3] Scoly corals range from brown to bright fluorescent greens, reds, and purples.
Members of this genus are commonly found in reef aquariums because of their slow growth,[2] however separation from other corals is necessary due to intense competition.[4] The slow growth rate of these corals is not well understood, but researchers have proposed that cyanobacterial mats may inhibit their growth or even cause shrinkage.[2][5]
Scolymia harness their energy mainly through a symbiotic relationship with zooxanthellate, a group of photosynthetic dinoflagellates. To a lesser degree, these corals can also feed heterotrophically using their tentacles to catch plankton drifting through the water at night.[2][3]
All Scolymia species are located in the Atlantic Ocean along the east coast of the Americas between Florida, through the Caribbean sea and Gulf of Mexico, and as far south as Brazil.[2][4] At higher latitudes, Scolymia tends to grow faster compared to at lower latitudes, likely as a result of annual mean temperature differences.[5] Scoly corals are typically found at the base of a reef between 10-80 m deep where there are turbid waters with low-light conditions.[6] Scolymia anchor in soft substrates where sediment continuously accumulates. They have adapted sediment-shifting abilities by growing upward on nearly-vertical surfaces in addition to a mucus exterior that prevents sedimentation from above.[2] This adaptation has allowed Scolymia to fill an ecological niche in which other corals are not able to survive.
Scoly corals have a unique ability to avoid both disease and predation from coralivorous fishes. The reasons for this are still largely unknown, however, it is believed that their bold colors may deter predators.[5][2]