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- Complete mitochondrial genome of the branching octocoral Paramuricea grayi (Johnson, 1861), phylogenetic relationships and divergence analysisPublication . Coelho, Márcio A. G.; Ledoux, Jean-Baptiste; Boavida, Joana; Paulo, Diogo; Gómez-Gras, Daniel; Bensoussan, Nathaniel; López-Sendino, Paula; Cerrano, Carlo; Kipson, Silvija; Bakran-Petricioli, Tatjana; Garrabou, Joaquim; EA, Serrao; Pearson, Gareth AnthonyThe Gray’s sea fan, Paramuricea grayi (Johnson, 1861), typically inhabits deep littoral and circalittoral habitats of the eastern temperate and tropical Atlantic Ocean. Along the Iberian Peninsula, where P. grayi is a dominant constituent of circalittoral coral gardens, two segregating lineages (yellow and purple morphotypes) were recently identified using single-copy nuclear orthologues. The mitochondrial genomes of 9 P. grayi individuals covering both color morphotypes were assembled from RNA-seq data, using samples collected at three sites in southern (Sagres and Tavira) and western (Cape Espichel) Portugal. The complete circular mitogenome is 18,668 bp in length, has an A þ T-rich base composition (62.5%) and contains the 17 genes typically found in Octocorallia: 14 protein-coding genes (atp6, atp8, cob, cox1-3, mt-mutS, nad1-6, and nad4L), the small and large subunit rRNAs (rns and rnl), and one transfer RNA (trnM). The mitogenomes were nearly identical for all specimens, though we identified a noteworthy polymorphism (two SNPs 9 bp apart) in the mt-mutS of one purple individual that is shared with the sister species P. clavata. The mitogenomes of the two species have a pairwise sequence identity of 99.0%, with nad6 and mt-mutS having the highest rates of non-synonymous substitutions.
- Not out of the Mediterranean: Atlantic populations of the gorgonian Paramuricea clavata are a separate sister species under further lineage diversificationPublication . A. G. Coelho, Márcio; Pearson, Gareth Anthony; Boavida, Joana; 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
- Seagrass connectivity on the west coast of Africa supports the hypothesis of grazer-mediated seed dispersalPublication . Tavares, Ana I; Assis, Jorge; Patrício, A. R.; Ferreira, Rogério; Cheikh, Mohamed Ahmed Sidi; Bandeira, Salomao; Regalla, Aissa; Silva Dos Santos, Iderlindo Jorge; Potouroglou, Maria; Nicolau, Suzana; Teodosio, MA; Almada, Carmen; Santos, Rui; Pearson, Gareth Anthony; Serrao, Ester A.Population connectivity influences the distribution of genetic diversity and divergence along a species range, as the likelihood of extinction or differentiation increases in isolated populations. However, there is still poor understanding of the processes mediating interpopulation dispersal in marine species that are sessile and lack planktonic life stages. One such case is the seagrass species Halodule wrightii, which produces basal seeds, although detached plants can drift. Along the tropical western coast of Africa, this species occurs in distant discontinuous habitats, raising the question of how interpopulation dispersal is mediated. The species is a key source of ecosystem functions including feeding large migratory grazers. This study aims to infer whether genetic differentiation of the seagrass H. wrightii along the western coast of Africa supports a hypothesis of predominant transportation of rafting seagrass by ocean currents, versus the hypothesis of biotic vectors of dispersal. Additional hypotheses were addressed concerning range-wide clonality and genetic diversity, assessed with microsatellite markers on populations of the west coast of Africa from Mauritania to Angola. Population genetic diversity and structure were compared with predictions from biophysical models of dispersal by oceanographic currents. The genetic data revealed low divergence among most populations, in strong contrast with predictions of very low probability of connectivity mediated by currents along the western African coastline. Moderate to high genotypic diversity showed important seed recruitment, but genetic and genotypic diversities were lower at range edges. Populations north and south of the equator were differentiated, and remarkably, so were neighboring equatorial populations despite their proximity. These results reveal independent sources of colonization of meadows in these islands, which are major habitat for migratory grazing green turtles, also supporting the hypothesis of biotically mediated seed transport. The importance of seagrass for conservation of endangered macrofauna has been widely reported; here we report evidence supporting the reciprocal role, that macrofauna protection can also plays a role in long-term survival and reproductive success of seagrass.