J. Reyes

Distribution of the Epiphytes along the Leaves of Cymodocea nodosa in the Canary Islands

The distribution of the epiphytes along the oldest leaf of shoots of Cymodocea nodosa was studied during a two-year cycle, from June 1990 to May 1992, in terms of number of species and cover. The difference in age between the base (the youngest part) and the apex (the oldest part) of the leaves allowed a study of the effect of the age of the host on the epiphyte community. A continuous increase in the number of species was observed along the oldest leaf of each shoot, from basal to apical segments. While the permanent epiphyte species were present everywhere, the seasonal and the occasional species were concentrated on the apical segments of the leaves and the occasional epiphytes showed their highest abundance in winter. The greatest development of the individuals, the high number of species as well as the high densities found towards the apical segments resulted in remarkable differences of cover along the leaves, from 0% at the basal segments to more than 600% reached at the apical segments in some months during the study period. The highest mean percentage cover by epiphytes on the oldest leaf of a shoot was detected in winter while the lowest was obtained in spring-summer. The Rhodophyta showed a quantitative dominance of more than 90% of cover in relation to the rest of the algal divisions, the Ceramiales and the Corallinales being the epiphytes which mainly contributed throughout the year. Results on cover and number of species of epiphytes permitted the distinguishing of three stages of development of the epiphytic community along the leaves: initiation, transition and maturity. Annual variations in the number of species as well as in the cover of the epiphytes along the oldest leaves were directly related to the growth rate and life-time of the leaves of Cymodocea nodosa. During the life-time of the leaves there was no succession of species in the epiphytic community but, from basal to apical segments, the epiphyte species were more developed and abundant, and the epiphytic community became more diverse.

Sublittoral and Deep-Water Red and Brown Algae New from the Canary Islands

Abstract Nine species of sublittoral and deep-water red and brown algae are reported from the Canary Islands for the first time. The reports of the Western Atlantic species Gloiocladia atlantica (Searles) R.E.Norris and Rosenvingea antillarum (P. et H.Crouan) M. J.Wynne are the first from the Eastern Atlantic Ocean. The presence of Feldmannophycus rayssiae (J. et G. Feldmann) Augier et Boudouresque, Fauchea repens (C.Agardh)Montagne et Bory and Halichrysis depressa (J.Agardh) F. Schmitz, previously known from the Mediterranean Sea and the adjacent Atlantic coasts, place their southernmost known limit of distribution in the Canary Islands. Stypopodium schimperi (Buchinger ex Kützing) Verlaque et Boudouresque is reported for the first time in the Atlantic Ocean, although it is present in the Mediterranean Sea, probably as a Lessepsian species. The records of the widely distributed Stylonema cornu-cervi Reinsch, Acrochaetium infestans M. Howe et Hoyt and Spatoglossum schroederi (C. Agardh) Kützing were not unexpected. Data concerning morphology, habitat and geographical distribution of these species are presented. Observations on the scantly documented sublittoral species Schimmelmannia schousboei (J.Agardh) J.Agardh and Dictyopteris plagiogramma (Montagne)Vickers are also given. In the dioecious Schimmelmannia schousboei, which has been formerly accepted as a doubtful record for the Canary Islands, the reproductive morphology is described including the previously unreported spermatangia. Dictyopteris plagiogramma was recently included in a checklist of Canarian species of Dictyopteris and is discussed in detail here.

Contribution to the Seaweed Flora of the Canary Islands: New Records of Florideophyceae

Seven species of Florideophyceae are reported from the Canary Islands for the first time: Predaea huismanii Kraft, Platysiphonia caribaea Ballantine et Wynne, Jania longifurca Zanardini, Spermothamnion flabellatum Bornet, Callithamnion decompositum J. Agardh, Helminthocladia agardhiana Dixon and Rissoella verruculosa (Bertolini) J. Agardh. Data concerning ecological conditions, geographical distribution, morphology, anatomy and phenology are presented. Observations on Platysiphonia miniata (C. Agardh) B0rgesen which has previously only been reported once from the Canary Islands, are also given.

New records of benthic marine algae from the canary Islands

Fourteen new records of marine algae from the Canary Islands are reported: Apoglossum ruscifolium (Turner) J. Agardh, Haraldia lenormandii (Derbes et Solier) J. Feldmann, Lomentaria subdichotoma Ercegovic, Myriogramme minuta Kylin, Predaea pusilla (Berthold) J. Feldmann, Rhodymenia ardissonei J. Feldmann, Cutleria chilosa (Falkenberg) Silva, Carpomitra costata (Stackhouse) Batters, Dictyopteris delicatula Lamouroux, Rosenvingea intricata (J. Agardh) Borgesen, Saccorhiza polyschides (Lightfoot) Batters, Sphacelaria plumula Zanardini, Cladophora hutchinsiae (Dillwyn) Kutzing and Halimeda discoidea Decaisne

Vegetative and reproductive morphology of Cladosiphon contortus, C. occidentalis and C. cymodoceae sp. nov. (Ectocarpales, Phaeophyceae) from the Canary Islands

M. Sansón, M.J. Martín and J. Reyes. 2006. Vegetative and reproductive morphology of Cladosiphon contortus, C. occidentalis and C. cymodoceae sp. nov. (Ectocarpales, Phaeophyceae) from the Canary Islands. Phycologia 45: 529–545. DOI: 10.2216/05-65.1 The genus Cladosiphon is represented in the Canary Islands by three species, C. contortus, C. occidentalis, and the new species C. cymodoceae. Vegetative and reproductive morphology of macrosporophytes, as well as habitat and phenology of the Canarian individuals, are described in detail. The southern limit of distribution of the northeastern Atlantic and Mediterranean species, C. contortus, is extended to the Canary Islands, and some anatomical features that previous descriptions had apparently overlooked (large inner medullary cells and rhizoid-like perimedullary filaments, longer cortical filaments, sheathed hairs, adventitious cortical filaments, and hairs often formed from inside empty plurilocular sporangia) are documented. Unilocular sporangia of C. contortus are described here for the first time, and they agree with the characteristics of the genus. Cladosiphon occidentalis is reported for the first time in the eastern Atlantic Ocean. Specimens previously reported from the Canary Islands as Cladosiphon zosterae were found to be misidentifications of C. occidentalis. Cladosiphon cymodoceae sp. nov., known only from the Canary Islands, is an epiphytic species on leaves of the warm temperate seagrass Cymodocea nodosa. Cladosiphon cymodoceae differs from the remaining species of the genus in a unique combination of characteristics: very irregularly branched habit with relatively thick axes and abundant short branchlets, long and thin cortical filaments (to 425 µm long and 5–8 µm lower diameter), sheathed hairs, and plurilocular sporangia with few-celled outgrowths of mature sporangia commonly at the apices of inrolled cortical filaments. Young thalli of C. occidentalis and C. cymodoceae were observed arising from myrionematoid crusts on leaves of Cymodocea nodosa as a juvenile stage in the development of the macroscopic sporophytes.

Vegetative and reproductive phenology of Zonaria tournefortii (Dictyotales, Phaeophyceae) in sublittoral populations off the Canary Islands

Abstract Sublittoral populations of Zonaria tournefortii off the Canary Islands were studied to monitor vegetative and reproductive phenology. Sterile individuals, sporophytes and gametophytes coexisted throughout the year, but significant differences were detected between seasons and life-history stages for most parameters tested. Density was maximal in autumn (3513 individuals m-2). Twenty-five percent of all individuals were fertile, with sporophytes at much higher densities than gametophytes in all seasons. The highest average individual thallus length occurred in winter, but the highest frequencies of long specimens and the greatest size inequalities were in summer. Fertile thalli were significantly longer than sterile thalli, however, sporophytes and gametophytes had similar average lengths. Populations exceeded 100% overall cover in all seasons (up to 552% in autumn), with highest cover occupied by fertile individuals. Overall biomass, produced mainly by sporophytes, was maximal in summer-autumn (981 g DW m-2). Results suggest that this perennial species exhibits a somewhat exceptional phenological pattern amongst dictyotaleans. Its phenology was regulated in most years by elevated water turbulence in early winter, which causes breakage or loss of whole individuals. Blade regeneration and recruitment from the remaining damaged individuals began in winter-spring, and continued until autumn. Individual growth, hierarchical structuring and maturation of populations occurred mainly in spring-summer. Optimal reproductive potential per individual occurred during summer, although the reproductive potential per unit area was similar among seasons.