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Molecular phylogeny based on concatenated sequences of chloroplast atpB, psaA, psbA, psbC and rbcL genes indicates that the filamentous brown alga Pilinia rimosa is phylogenetically distant from the Ectocarpales, in which it has been classified (as Waerniella lucifuga). In the tree, Pilinia was sister to the clade comprised of Ishige and Petroderma (Ishigeales) supported by high statistical values. Observations of unialgal P. rimosa cultures originating from Helgoland (Germany), England (UK), Woods Hole (USA) and Newfoundland (Canada) showed a direct type of life history with reproduction by characteristic unilocular zoidangia typically forming only four zoids. Despite the description of plurilocular zoidangia in Kuckuck's account as well as in later publications, we conclude that those observations were based on misinterpretation of the very small unilocular zoidangia formed in series, often with longitudinal walls between zoidangia. Pilinia rimosa grows in caves or crevices in rocks, and on walls or wood pilings in deep shade in the upper intertidal and spray zone, and is therefore regarded as a marine species, but it could also survive and mature in freshwater medium. We propose the establishment of a new family Piliniaceae for Pilinia and place it in Ishigeales. Molecular and morphological analysis of the culture strains, SAG 124.79 and SAG 2381, identified as the euryhaline alga Porterinema fluviatile, indicated that SAG 124.79 is in fact P. rimosa. However, SAG 2381 is true P. fluviatile, also displaying the characteristic plurilocular zoidangia. Porterinema was shown to be a member of the Chordariaceae, Ectocarpales sensu lato. [ABSTRACT FROM AUTHOR]

Dictyosiphon asiaticus sp. nov. and D. sparsus sp. nov. are newly described from Japan and the north-western Pacific. Molecular phylogenies based on the mitochondrial cox1 and cox3 and chloroplast atpB, psaA, psbA and rbcL DNA sequences revealed that Dictyosiphon comprises at least seven lineages worldwide. Japanese Dicytosiphon species formed two clades with high support and were sister to a clade including specimens from the cold-water regions of the northern Pacific, the Arctic, and the north-western Atlantic. Specimens of one of the Japanese clades (= D. asiaticus sp. nov.) were morphologically similar to D. foeniculaceus (generitype described from Scotland, UK), having densely branched thalli with fine branches, and were epiphytic on Scytosiphon spp. and Chordaria spp. Specimens of the other Japanese clade (= D. sparsus sp. nov.) were morphologically similar to D. chordaria, having somewhat thicker, sparse branches with blunt tips, and were epiphytic on Chordaria spp. We assign the third clade distributed on both sides of the North Pacific to D. sinicola, which was described from Washington, USA, for the following reasons: Dictyosiphon specimens in the region having relatively densely branched thalli with fine tips have been identified as D. foeniculaceus, and D. sinicola was distinguished from them by its remarkably larger thallus, while anatomically they are very similar. However, D. foeniculaceus is not widely distributed in the region, with only one genetic lineage (species) reported, so that those two taxa are considered to be ecotypes of the same species, and D. sinicola is the valid name for the taxon. [ABSTRACT FROM AUTHOR]

Taxonomy, species diversity, and geographical distribution of the marine brown algal genus Padina (Dictyotales, Phaeophyceae) from tropical South-East Asian waters were investigated through a combination of morphological and molecular analyses. The study presents a new schematic diagram showing a suite of morphological characters including thallus hairline structures that are useful for species delineation in the genus. This study also revealed two new species from Myanmar, P. gracilis sp. nov. and P. lata sp. nov. based on molecular and morphological data. P. gracilis is characterised by a 2-layered thallus, thin hairlines on both surfaces of the thallus at equal distances, non-indusiate reproductive sori distally very close to the hairlines on the inferior surface, and the presence of Vaughaniella stage. P. lata is characterized by a 2–4-layered tiny thallus, broad hairlines located only on the inferior thallus surface, non-indusiate reproductive sori abutting the hairlines on the inferior surface and irregularly spreading on the superior surface, and the presence of Vaughaniella stage. This study also revealed new distributional records for four Padina species: P. okinawaensis from Myanmar and P. fasciata, P. ryukyuana and P. terricolor from the Philippines. These findings point to elevated species diversity in central Indo-Pacific waters. This study confirmed that most of the Padina species in the Pacific regions are showing overlapping distribution across the regions, in contrast to species from the Indian Ocean, which tend to be confined to specific localities. [ABSTRACT FROM AUTHOR]

The reproductive structures, early development and carotenoid composition of Umbraulva kuaweuweu, which is a deep-water ulvacean species recently reported from Hawaii, are reported for the first time using the specimens collected by dredging at ~30 m depth from Ogasawara Islands and Mageshima in southern Japan. Although Umbraulva kuaweuweu had siphonaxanthin as in U. japonica, a characteristic carotenoid of Umbraulva, U. kuaweuweu lacked α-carotene and β-carotene. U. kuaweuweu differed markedly from U. japonica in thallus morphology and reproductive structures: cell shape, presence/absence of inner rhizoidal filaments in the upper parts of thalli, solid/partly saccate thalli, and developmental processes of zoids. Multigene concatenated DNA sequences of chloroplast rbcL and tufA genes, and nuclear 18S, 5.8S, 28S rDNA and rDNA ITS1 and ITS2 regions indicated separation of U. kuaweuweu from the clade comprised of the generitype U. japonica, U. amamiensis, U. dangeardii and U. kaloakulau. In conclusion, based on the distinctive morphology, life history, carotenoid composition and molecular phylogeny, we propose the establishment of a new genus Ryuguphycus gen. nov. to accommodate U. kuaweuweu, as R. kuaweuweu comb. nov. [ABSTRACT FROM AUTHOR]

A study of the genus Padina in the Mediterranean Sea, based on detailed morphological and molecular analyses using chloroplast rbcL and mitochondrial cox3 gene sequences, as well as RuBisCO spacer and partial rbcS sequences, revealed the presence of two new species, P. ditristromatica Ni-Ni-Win & H. Kawai and P. pavonicoides Ni-Ni-Win & H. Kawai. They are two to three-layered and three-layered species, respectively. Padina ditristromatica is characterized by a thallus composed of two cell layers from the marginal portion to the inrolled margin and a mixture of two and three layers in the other portions; heavy calcification on both surfaces of the thallus except for the hair lines; alternating hair lines that are spaced at unequal distances between the upper and lower surfaces; and broad indusiate oogonial and tetrasporangial sori forming broken lines or patches arranged in a concentric row, which are distally close to the hair lines and half immersed in the epidermis layer only on the lower surface. Padina pavonicoides is characterized by a thallus composed of three cell layers from the base to the marginal portion and two layers at the inrolled margin; alternating hair lines that are spaced at equal distances between the upper and lower surfaces; and indusiate oogonial and tetrasporangial sori forming patches located distal to the hair lines only on the lower surface. All molecular phylogenetic analyses indicated that the new species are closely related to P. pavonica, a common species in the Mediterranean Sea. However, the cox3 region could not be amplified for P. ditristromatica. Therefore, the RuBisCO spacer and partial rbcS were analysed for the Mediterranean specimens in order to confirm their identity as well as their closest relationships. The combined rbcL, RuBisCO spacer and partial rbcS data also support their genetic separation and show that P. pavonica is more closely related to P. pavonicoides than P. ditristromatica, as in other molecular analyses. [ABSTRACT FROM AUTHOR]