Reproductive and genetic variation among Caribbean gorgonians: The differentiation of Plexaura kuna, new species

Ecophenotypic variation is common among many coral reef benthic invertebrates. How-ever, there is no consensus on whether this variation is generated by genetically diverse and phenotypically plastic species or whether it is indicative of a more species-rich fauna than previously believed. Caribbean gorgonian species exhibit extensive variation in their sclerites and based on the variation among populations in the genus Plexaura, we describe P. kuna, new species. The sclerites of P. kuna are most similar to those of Plexaura homomalla but differ both qualitatively and quantitatively from those of P. homomalla and other congeners. Analysis of randomly amplified polymorphic DNA (RAPDs) indicates that P. kuna has alleles that are absent in both Plexaura homomalla and Plexaura homomalla forma kükenthali. The reproductive cycle of P. kuna in Panama differs from that of P. homomalla and there is only limited opportunity for hybridization between the two species. Genetic and reproductive data can serve as important adjuncts in establishing the existence of species-level differences between morphologically distinct populations.