Browsing by Author "Aurelle, Didier"
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- Fuzzy species limits in Mediterranean gorgonians (Cnidaria, Octocorallia): inferences on speciation processesPublication . Aurelle, Didier; Pivotto, Isabelle D.; Malfant, Marine; Topcu, Nur E.; Masmoudi, Mauatassem B.; Chaoui, Lamya; Kara, Hichem M.; Coelho, Márcio; Castilho, Rita; Haguenauer, AnneThe study of the interplay between speciation and hybridization is of primary importance in evolutionary biology. Octocorals are ecologically important species whose shallow phylogenetic relationships often remain to be studied. In the Mediterranean Sea, three congeneric octocorals can be observed in sympatry: Eunicella verrucosa, Eunicella cavolini and Eunicella singularis. They display morphological differences and E.singularis hosts photosynthetic Symbiodinium, contrary to the two other species. Two nuclear sequence markers were used to study speciation and gene flow between these species, through network analysis and Approximate Bayesian Computation (ABC). Shared sequences indicated the possibility of hybridization or incomplete lineage sorting. According to ABC, a scenario of gene flow through secondary contact was the best model to explain these results. At the intraspecific level, neither geographical nor ecological isolation corresponded to distinct genetic lineages in E.cavolini. These results are discussed in the light of the potential role of ecology and genetic incompatibilities in the persistence of species limits.
- Not out of the Mediterranean: Atlantic populations of the gorgonian Paramuricea clavata are a separate sister species under further lineage diversificationPublication . Coelho, Márcio; Pearson, Gareth; Boavida, Joana R. H.; Paulo, Diogo; Aurelle, Didier; Arnaud‐Haond, Sophie; Gómez‐Gras, Daniel; Bensoussan, Nathaniel; López‐Sendino, Paula; Cerrano, Carlo; Kipson, Silvija; Bakran‐Petricioli, Tatjana; Ferretti, Eliana; Linares, Cristina; Garrabou, Joaquim; Serrão, Ester A.; Ledoux, Jean‐BaptisteThe accurate delimitation of species boundaries in nonbilaterian marine taxa is notoriously difficult, with consequences for many studies in ecology and evolution. Anthozoans are a diverse group of key structural organisms worldwide, but the lack of reliable morphological characters and informative genetic markers hampers our ability to understand species diversification. We investigated population differentiation and species limits in Atlantic (Iberian Peninsula) and Mediterranean lineages of the octocoral genus Paramuricea previously identified as P. clavata. We used a diverse set of molecular markers (microsatellites, RNA-seq derived single-copy orthologues [SCO] and mt-mutS [mitochondrial barcode]) at 49 locations. Clear segregation of Atlantic and Mediterranean lineages was found with all markers. Species-tree estimations based on SCO strongly supported these two clades as distinct, recently diverged sister species with incomplete lineage sorting, P. cf. grayi and P. clavata, respectively. Furthermore, a second putative (or ongoing) speciation event was detected in the Atlantic between two P. cf. grayi color morphotypes (yellow and purple) using SCO and supported by microsatellites. While segregating P. cf. grayi lineages showed considerable geographic structure, dominating circalittoral communities in southern (yellow) and western (purple) Portugal, their occurrence in sympatry at some localities suggests a degree of reproductive isolation. Overall, our results show that previous molecular and morphological studies have underestimated species diversity in Paramuricea occurring in the Iberian Peninsula, which has important implications for conservation planning. Finally, our findings validate the usefulness of phylotranscriptomics for resolving evolutionary relationships in octocorals.
- On the specific status of eastern mediterranean dendrophyllia corals (Cnidaria, Anthozoa): genetic characterization and speciation scenariosPublication . Aurelle, Didier; Haguenauer, Anne; Blaise, Chloé; Reynes, Lauric; Arnaud‐Haond, Sophie; Boavida, Joana; Cabau, Cédric; Klopp, Christophe; Lundalv, Tomas; Noûs, Camille; Sartoretto, Stéphane; Wienberg, Claudia; Jiménez, Carlos E.; Orejas, CovadongaThe 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.
- A well-kept treasure at depth: precious red coral rediscovered in Atlantic deep coral gardens (SW Portugal) after 300 yearsPublication . Boavida, Joana; Paulo, Diogo; Aurelle, Didier; ARNAUD-HAOND, Sophie; Marschal, Christian; Reed, John; Gonçalves, J. M. S.; Serrão, EsterThe highly valuable red coral Corallium rubrum is listed in several Mediterranean Conventions for species protection and management since the 1980s. Yet, the lack of data about its Atlantic distribution has hindered its protection there. This culminated in the recent discovery of poaching activities harvesting tens of kg of coral per day from deep rocky reefs off SW Portugal. Red coral was irregularly exploited in Portugal between the 1200s and 1700s, until the fishery collapsed. Its occurrence has not been reported for the last 300 years.