Sexual reproduction in the Caribbean coral genus Isophyllia (Scleractinia: Mussidae) in Puerto Rico

The sexual pattern, reproductive mode, and timing of reproduction of Isophyllia sinuosa and Isophyllia rigida, two Caribbean Mussids, were assessed by histological analysis of specimens collected monthly during 2000-2001. Results indicate that both species are simultaneous hermaphroditic brooders, with a single annual gametogenetic cycle. Spermatocytes and oocytes of different stages were found within the same mesentery indicating sequential maturation for extended planulation. Oocytes begin development 7-8 months prior to spermaries; beginning in May in I. sinuosa and August in I. rigida . Gametes of both sexes matured simultaneously; May-June in I. rigida and March-April in I. sinuosa . Planulae were observed in I. sinuosa during April and in I. rigida from June through September. Significantly higher polyp and mesenterial fecundity were found in I. rigida compared to I. sinuosa . Significantly larger oocyte sizes were found in I. sinuosa than in I. rigida, however significantly larger planula sizes were I. rigida compared to I. sinuosa. Hermaphroditism is the exclusive sexual pattern within the Mussidae; brooding has also been documented within the related Mussid genera Mussa, Scolymia and Mycetophyllia . These results represent the first description of the sexual characteristics of I. rigida and refute the previous description for I. sinuosa.