Distinção de espécies de Amphimedon Duchassaing & Michelotti, 1864 (Niphatidae, Haplosclerida, Demospongiae) da costa brasileira por estudos de diversidade genética e morfológica

Abstract

The taxonomy of Amphimedon is complicated due to its wide distribution and abundance of morphotypes. The objective of this work was to characterize the species of Amphimedon from the Brazilian Coast by the combined study of morphology and DNA polymorphisms. The samples utilized were derived from the collections of Museu Nacional (MNRJ, and comprised Amphimedon viridis, A. compressa e A. aff. compressa. The genomic DNA was extracted and the regions of the internal transcribed spacers (ITS-1 and ITS-2) coding for nuclear ribossomal RNA were amplified. After amplifications, samples were subjected to the Single Strand Conformation Polimorphism (SSCP) technique. The individuals of Amphimedon viridis show a similar ITS 1 migration pattern, even when coming from distant collecting localities on the Brazilian Coast. The results presented support the idea that A. aff. compressa comprises distinct species when we utilize ITS 1 regions as a molecular character. In the same way, these results indicate the possibility that A. viridis from the northeastern and southeastern Brazilian regions are conspecific, occurring homogeneously along the Brazilian coast. Our results enabled the differentiation of Amphimedon species through the combined PCR-SSCP technique, showing the potential use of this method for the distinction of species of marine sponges.