Last year in Bonaire (Dutch Caribbean) I encountered this strange colony of the scleractinean coral Siderastrea siderea. It has circular patches of a few cms across with smaller polyps, the smallest in the center. Has anybody seen this as well and what causes this strange growth?
Wow, I´ve never seen anything like it in the MBRS reef (where I work, Mexico reefs in specific). Its quite an interesting pattern, I can only come to the thought that this specific colony is showing abnormal grwoth, an opposite version to hyperplasia which affects several species in the Caribbean...
For comparison I have added a photo of a normal Siderastrea siderea. In this colony, corallites are of equal size and the colony has a smooth surface. Possibly, the irregular corallites between the circular patches in the first photo indicate local hypertrophy. In case they are larger than average, and presuming a normal origin of the colony, other polyps may get less space and concentrate in round shallow cups. No answer to my original questions, but maybe this explains the process by which this pattern develops.