Algal systematics and taxonomy in the Marine Biodiscovery Programme

Proceedings of the 2nd Annual Beaufort Marine Biodiscovery Research Workshop (Galway, 10-11 Dicembre 2009) - Abstrac

Sequencing type material resolves the identity and distribution of the generitype Lithophyllum incrustans, and related European species L. hibernicum and L. bathyporum (Corallinales, Rhodophyta)

DNA sequences from type material in the nongeniculate coralline genus Lithophyllum were used to unambiguously link some European species names to field-collected specimens, thus providing a great advance over morpho-anatomical identification. In particular, sequence comparisons of rbcL, COI and psbA genes from field-collected specimens allowed the following conclusion: the generitype species, L. incrustans, occurs mostly as subtidal rhodoliths and crusts on both Atlantic and Mediterranean coasts, and not as the common, NE Atlantic, epilithic, intertidal crust reported in the literature. The heterotypic type material of L. hibernicum was narrowed to one rhodolith belonging in Lithophyllum. As well as occurring as a subtidal rhodolith, L. hibernicum is a common, epilithic and epizoic crust in the intertidal zone from Ireland south to Mediterranean France. A set of four features distinguished L. incrustans from L. hibernicum, including epithallial cell diameter, pore canal shape of sporangial conceptacles and sporangium height and diameter. An rbcL sequence of the lectotype of Lithophyllum bathyporum, which was recently proposed to accommodate Atlantic intertidal collections of L. incrustans, corresponded to a distinct taxon hitherto known only from Brittany as the subtidal, bisporangial, lectotype, but also occurs intertidally in Atlantic Spain. Specimens from Ireland and France morpho-anatomically identified as L. fasciculatum and a specimen from Cornwall likewise identified as L. duckerae were resolved as L. incrustans and L. hibernicum, respectively

Studies on maerl/rhodolith-forming species (Corallinales: Rhodophyta): a molecular perspective of their diversity

Riassunti della riunione scientifica annuale del Gruppo di Lavoro per l'Algologia della Società Botanica Italiana (Ancona, 4-5 Novembre 2011) - Abstrac

Evolutionary history and diversity of Mediterranean coralline algae: how much do we know?

In the Mediterranean Sea coralline red algae play a particularly important role, as their calcified thalli provide hard substratum in several benthic biocenoses covering large portions of rocky bottom (i.e. coralligenous concretions, rims of Lithophyllum byssoides, rims of articulated corallines). Since its opening 250 Myr ago, the Mediterranean has undergone a complex oceanographic history, due to geological and climatic events such as the Atlantic opening, the isolation from the Indian Ocean, and the Messinian Salinity Crisis, which determined phases of connection and separation from the adjacent oceans. These events profoundly affected the evolutionary history of Mediterranean marine organisms, fueling a high biological diversity. Paleontological evidence indicates that corallines have been major bioconstructors in the Mediterranean for a long time and that some common species have occurred in the basin for at least 10-11 Myr (Lithophyllum dentatum, L. incrustans, L.\ua0pustulatum). The limited amount of molecular data available has hindered our understanding of the evolution and diversity of this group, but recent studies provide major insights in these topics. The recent discovery of Pneophyllum cetinaensis shows that the Mediterranean is the only geographical region in which coralline algae have successfully crossed the border between sea and freshwater, a transition that probably took place during the last glaciation. Lithophyllum byssoides, one of the few genuinely intertidal Mediterranean seaweeds, has a high haplotypic diversity and Mediterranean populations probably represent different species from Atlantic populations, a pattern observed for many animal species. Similarly sharp haplotypic differentiation between Mediterranean and Atlantic populations has been documented for species of Mesophyllum and Corallina. Lithophyllum cabiochiae, the main bioconstructor of coralligenous concretions, represents a highly diverse complex of species, rather than a single species. These studies suggest that Mediterranean corallines represent a more evolutionarily complex group than believed so far, worthy of further detailed investigation

Detection of gametophytes in the maerl-forming species Phymatolithon calcareum (Melobesioideae, Corallinales) assessed by DNA barcoding

International audienceFertile gametangial plants of Phymatolithon calcareum, which are seldom reported in the Atlantic European coasts, were collected as encrusting, epilithic plants in a subtidal maerl bed in Brittany (France). Based on their morphological features, the plants were identified as P. calcareum. This identification was further confirmed by DNA barcodes using as a reference COI-5P sequences obtained from the neotype together with recent collections from the Atlantic European maerl beds. The reproductive structures were empty but they were regarded as mature female conceptacles. Compared to the two previous records of gametangial plants of P. calcareum for the Atlantic European waters, the uniporate conceptacles observed in this study are larger, and were collected at a different time of the year. To our knowledge, this is the first time that the occurrence of gametangial plants of P. calcareum is corroborated with molecular tools (DNA barcodes)

Lithophyllum congestum (Corallinales, Rhodophyta), what are you and what aren't you? Receiving some inner signals from DNA and morpho-anatomy to clarify our understanding on the species

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