Sexual reproduction in the Caribbean coral genusIsophyllia(Scleractinia: Mussidae)
The sexual pattern, reproductive mode, and timing of reproduction ofIsophyllia sinuosaandIsophyllia rigida, two Caribbean Mussids, were assessed by histological analysis of specimens collected monthly during 2000–2001. Both species are simultaneous hermaphroditic brooders characterized by a single annual gametogenetic cycle. Spermatocytes and oocytes of different stages were found to develop within the same mesentery indicating sequential maturation for extended planulation. Oogenesis took place during May through April inI. sinuosaand from August through June inI. rigida. Oocytes began development 7–8 months prior to spermaries but both sexes matured simultaneously. Zooxanthellate planulae were observed inI. sinuosaduring April and inI. rigidafrom June through September. Higher polyp and mesenterial fecundity were found inI. rigidacompared toI. sinuosa. Larger oocyte sizes were found inI. sinuosathan inI. rigida, however larger planula sizes were found inI. rigida. Hermaphroditism is the exclusive sexual pattern within the Mussidae while brooding has been documented within the related generaMussa,ScolymiaandMycetophyllia. This study represents the first description of the sexual characteristics ofI. rigidaand provides an updated description ofI. sinuosa.