Loading...
2 results
Search Results
Now showing 1 - 2 of 2
- Genetic affinities and biogeography of putative Levantine-endemic seaweed Treptacantha rayssiae (Ramon) M.Mulas, J.Neiva & A.Israel, comb. nov. (Phaeophyceae)Publication . Mulas, Martina; Neiva, J.; Sadogurska, Sofia S.; Ballesteros, Enric; Serrao, Ester; Rilov, Gil; Israel, AlvaroCystoseira sensu lato (Ochrophyta) forests are important habitat formers in the Mediterranean Sea, but they have mostly been studied in the western basin where many species are under decline. In the eastern basin, where fewer species occur, Cystoseira rayssiae Ramon was described in the year 2000 as an endemic species based on morphological characteristics from herbaria samples collected on the Israeli coast. No further investigations have been conducted on this peculiar species since, but recently it has been recorded in contiguous Lebanon and outside the Mediterranean. Our work was aimed at confirming the taxonomic validity and endemic nature of this species, including its position among the recently split Cystoseira sensu stricto, Carpodesmia Greville and Treptacantha Kutzing genera, by sequencing the mitochondrial COI gene and by examining morphological characteristics in samples from three different sites in northern Israel. Notwithstanding considerable morphological plasticity, molecular analyses revealed a single unique COI sequence. Phylogenetic analyses show that Cystoseira rayssiae belongs to the resurrected genus Treptacantha and hence, the new combination Treptacantha rayssiae (Ramon) M.Mulas, J.Neiva & A.Israel, comb. nov., is proposed. Unique sequences and a restricted range support its Levantine-endemic status. Intriguing extra-Mediterranean reports from the Red Sea and the Persian Gulf are probably misidentifications rather than reflecting a disjunct distribution or recent invasion.
- DNA barcoding reveals cryptic diversity, taxonomic conflicts and novel biogeographical insights in Cystoseira s.l. (Phaeophyceae)Publication . Neiva, J.; Bermejo, Ricardo; Medrano, Alba; Capdevila, Pol; Milla-Figueras, David; Afonso, Pedro; Ballesteros, Enric; Sabour, Brahim; Serio, Donatella; Nóbrega, Eduardo; Soares, João; Valdazo, José; Tuya, Fernando; Mulas, Martina; Israel, Álvaro; Sadogurska, Sofia S.; Guiry, Michael D.; Pearson, Gareth; Serrao, EsterCystoseira sensu lato (s.l.) - encompassing the genera Cystoseira sensu stricto (s.s.), Ericaria and Gongolaria - is a diverse group of forest-forming brown macroalgae endemic to the warm-temperate North-east Atlantic. These algae have immense biogeographic and ecological significance and have been experiencing recent regional declines. Most Cystoseira s.l. display important morphological plasticity and can be confused with similar species. Therefore, species boundaries, geographic ranges and phylogenetic affinities remain imprecise for most. In the face of persistent taxonomic difficulties, several authors underlined the necessity for new molecular-based approaches, but studies so far lacked representativity, resolution and standardization. To fill in these gaps, in this study we sequenced a comprehensive collection of Cystoseira s.l. spanning its entire North-east Atlantic range for a similar to 1200 bp cox1 barcode, and sequenced selected individuals representing major genetic entities for a few additional plastid markers. Phylogeographic, phylogenetic and species delimitation methods revealed 27 Molecular Operational Taxonomic Units, including unaccounted cryptic diversity, and elucidated with unprecedented resolution species compositions and phylogenetic relationships within each genus. Some entities within the lineages Cystoseira compressa/humilis, Ericaria brachycarpa/crinita, E selaginoides and tophulose Gongolaria, as well as among free-living algae, conflicted with a priori taxonomic assignments, and required the redefinition, reinstatement and recognition of new taxa. For some, diagnostic mutations and biogeography were more useful for species identifications than morphological characters or conventional barcoding gaps. A few species showed narrow geographic ranges and others were the sole representatives of their respective lineages. Several sister-species showed Atlantic vs Mediterranean complementary ranges. phylogenetic signal of coxl was nevertheless insufficient to confidently determine patterns of lineage splitting in several lineages and species complexes and did not improve significantly with additional plastid markers. We discuss novel systematics and biogeography insights considering the advantages and shortcomings of the barcoding approach employed, and how this comprehensive baseline study can be expanded to address multiple questions still left unanswered.