Speciation in the Hamlets (Hypoplectrus: Serranidae): A Continuing Enigma

The hamlets (Hypoplectrus) are simultaneously hermaphroditic, carnivorous, largely territorial seabasses (Serranidae), limited almost entirely to the tropical Western Atlantic. Several of the morphospecies in the genus are largely sympatric and syntopic, but morphologically, all are remarkably similar in every major feature except color pattern. Even here, intermediate individuals are occasionally encountered. Hamlets are gleaning predators, and foraging behavior is similar in all observed morphospecies except H. indigo, in which larger individuals were found to feed mostly on the planktivorous pomacentrid Chromis cyaneus. H. indigo also matures at a larger size than other hamlets. Reproductive behavior is similar in all morphospecies. Matings between morphospecies have been observed infrequently and only between morphospecies of most similar color pattern. Overall, the evidence suggests that hamlets form a multispecies complex, with restricted exchange of genes among sympatric morphospecies. The results neither support nor refute the idea that hamlets are aggressive mimics, but they do suggest that at least some of the cases where color patterns of hamlets appear to have converged with those of sympatric noncarnivorous fishes can be accounted for by the operation of similar selective pressures on both putative model and mimic, rather than the occurrence of aggressive mimicry.