On the specific status of eastern Mediterranean Dendrophyllia corals (Cnidaria, Anthozoa): Genetic characterization and speciation scenarios

The deep-sea corals Dendrophyllia ramea and Dendrophyllia cornigera occur in Mediterranean and Atlantic waters. Both species are found in different environmental conditions, and they can colonize hard and soft substrates. These species then display an important ecological plasticity along with morphological plasticity. Nevertheless, there is a large knowledge gap on the genetic characteristics of the two species, including on the relationships between them and the possibility of cryptic species along their range. The recent discovery of Dendrophyllia populations off Cyprus in the eastern Mediterranean Sea raised new questions in this context. These corals were related to D. ramea but had some morphological differences with other known populations of this species. Here, we study the specific status of Dendrophyllia corals from Cyprus on the basis of morphology and genetics. The genetic data are interpreted by comparison with the same analysis performed on two Caryophyllia species. Both morphological and genetic data confirm that corals found off Cyprus belong to the D. ramea species. We further tested the speciation scenario using transcriptome data: the results indicate an absence of current gene flow between D. ramea and D. cornigera and that the divergence occurred more than 3 million years ago. We discuss the possible historical and ecological factors which may have shaped speciation in these species.

Cyclamen funding: CYCLAMEN project, funded by TOTAL foundation (grant number BIO_2014_091_Juin_CS-8). This study has received funding from the European Union's Horizon 2020 research and innovation program under the project, grant agreement No 818123 (iAtlantic). This output reflects only the author's view, and the European Union cannot be held responsible for any use that may be made of the information contained therein. The project leading to this publication has received funding from European FEDER Fund under project 1166-39417. The project leading to this publication has received funding from Excellence Initiative of Aix-Marseille University - A*MIDEX, a French “Investissements d'Avenir” programme.

Peer reviewed