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The poorly known red alga Gelidiella ramellosa (Kützing) Feldmann et Hamel is described from specimens collected near the type locality in Western Australia. Plants occur as turfs to 1-2 cm in height, with prostrate stolons attached by clusters of rhizoids to rock. Erect axes are irregularly pinnately branched and terete to slightly compressed. Structurally, the medulla is pseudoparenchymatous with no discernable central axis, and rhizines are absent. Spermatangia occur in surface son. Tetrasporangia are borne in irregular whorls in terete, basally constricted stichidia that are lateral on erect axes. LSU nrDNA and rbcL sequence analyses clearly place G. ramellosa in a dade containing species of Gelidiella and Parviphycus, but are equivocal regarding its relationship with either genus. [ABSTRACT FROM AUTHOR]

A morphological and gene sequence study has shown the red algal genus Stenopeltis to be a member of the Liagoraceae (Nemaliales), not the Polyidaceae (Gigartinales) where it was placed after being segregated from Rhodopeltis . Post-fertilization events in Stenopeltis gracilis (the type of the genus) include a spreading, diffuse gonimoblast arising directly from the zygote ( = post-fertilization carpogonium), and no auxiliary cells, features characteristic of the Liagoraceae. Moreover, phylogenetic analyses based on LSU (large subunit) rDNA sequences clearly place Stenopeltis in a clade with members of the Liagoraceae. These observations are at odds with the existing taxonomic placement of the genus and a re-interpretation of earlier observations purporting to show the presence of auxiliary cells is presented. The morphology and reproduction of the three species currently attributed to the genus, S. gracilis (the type), S. setchelliae , and S. liagoroides , are described. LSU sequences as well as carpogonial branch and cystocarp morphology of S. setchelliae are distinct from those of S. gracilis (the type), and the segregate genus Akalaphycus is proposed to accommodate S. setchelliae and S. liagoroides . [ABSTRACT FROM AUTHOR]

Recent morphological and genetic studies on the Caulerpa racemosa (Forsskål) J. Agardh complex have demonstrated that three taxa occur in the Mediterranean Sea. One of them, the 'invasive variety', provisionally regarded as close to C. racemosa var. occidentalis J. Agardh, is currently spreading spectacularly throughout the Mediterranean. On the basis of new morphological and molecular studies (rDNA ITS1, 5.8S and ITS2 sequences), we confirm here that this invasion is the result of a recent introduction and we identify the invasive variety as Caulerpa cylindracea Sonder, endemic to south-west Australia, and currently known as C. racemosa var. laetevirens f. cylindracea (Sonder) Weber-van Bosse. C. cylindracea differs from the tropical north Australian C. laetevirens Montagne by its slender thallus, lack of large rhizoidal pillars, the slight inflation of the basal part of the upright axes immediately above the attachment to the stolon, by the range of morphological variations (branchlets clavate to cylindrical but never trumpet-like or shield-like) and by the rDNA ITS sequence data. The new combination C. racemosa var. cylindracea (Sonder) Verlaque, Huisman et Boudouresque is therefore proposed. [ABSTRACT FROM AUTHOR]

Describes Ditria expleta, a new red algal species from Western Australia. Detection of Ditria expleta in Diplerosiphonia and Herposiphonia; Capacity of the algal cells of the ventral pericentral siphon to produce digitate holdfasts; Inclusion of Ditria in the tribe Polysiphonieae.

Asteromenia gen. nov. (Rhodymemates, Rhodophyta) is proposed with a single species. Asteromenai pe;tata (W.R.Taylor) comb nov. (basionym: Fauchea peltata W.R.Taylor). Thalli of the proposed new genus are stipitate with dorsiventral, peltate blades that are initially circular in shape but with age become stellate with ligulate arms. Internally, the blades have a polystromatic medulla of large hyaline cells, grading into a cortex of smaller, pigmented cells. Clusters of translucent cells occur on the dorsal surface of the blade. Tetrasporangia are formed by transformation of intercalary midcortical cells. Mature tetrasporangia have cruciately arranged spores and are densely aggregated in the cortex, mostly on the ventral surface, but occasional tetrasporangia also arise on the dorsal surface. Carpogonial branches are four-called and arise on inner cortical cells. Auxiliary cells are borne on auxiliary mother cells attached to supporting cells of the carpogonial branches. Cystocarps are protuberant, with well-devoloped, ostiolate pericarps that often have extended, proboscis-like necks. The new genus differs from the previously described peltate or dorsiventral taxa in the Rhodymeniaceae by its polystromatic medulla (Maripelta and Sciadophycus have a monostromatic medulla (Maripelta and Sciadophycus have a monostromatic medulla), intercalary tetrasporangia formed in an unmodified cortex, and four-celled carpogonial branches (Halichrysis, as typified by H.depressa (J.Agardh) F. Schmitz, has terminal tetrasporangia in nemathecia and three-celled carpogonial branches. [ABSTRACT FROM AUTHOR]

Dicroglossum gen nov. (Delesseriaceae, Ceramiales) is a monotypic genus based on Delesseria crispatula, a species originally described by Harvey for plants collected from southwestern Western Australia. Distinctive features of the new genus include exogenous indeterminate branches; growth by means of a single transversely dividing, apical cell; absence of intercalary divisions in the primary, secondary, and tertiary cell rows, lateral pericentral cells not transversely divided; not all cells of the secondary cell rows producing tertiary cell rows; all tertiary initials teaching the thallus margin; midrib present but lateral nerves absent; determinate lateral bladelets arising endogenously; blades monostromatic, except at the midrib; carpogonial branches restricted to primary cell rows on both surfaces of unmodified blades,; procarps produced on both blde surfaces, each procarp conststing of a supporting cell that bears two four-celled carpogonial branches and one sterile-cell groupof three to four cells; and tetrasporangia borne in two layers, separated by a central row of sterile cells. The combination of exogenous indeterminate branching and bicarpogonial procarps is considered to warrant the recongnition of a new tribe, the Dicroglosseae, within the subfamily Delesserioideae. [ABSTRACT FROM AUTHOR]

Describes three new species of the genus Balliella Itono and Tanaka from eastern Australia. Production of either abaxial or adaxial gland cells from the basal cells of lateral branches; Restriction of tetrasporangia to short branches; Implications on phycology.

The new propagule-forming red algae from southern Australia, Deucalion levirnii(Lindauer) gen. Et comb. Nov. and Anisoschizus propaguli gen. Et sp. nov., are described and defined largely on their development in laboratory culture. Deucalion is included in the tribe Comp-sothamnieae on the basis of its subapical procarp and alternate disticlous branching. It differs from the other genera included in that tribe in that it produces 3-celled propagules, polysporangia, a subapical cell of the fertile axis which bears 3-pericentral cells, and an apparently post-fertilization involucre which develops from the hypogenous and sub-hypogenous cells of the fertile axis. Its gametophyle morphology has been elucidated in culture, as only sporophytes are known from the field. Gametophytes do not appear to produce propagules. Anisoschizus is provisionally included in the tribe Spermothamnieae on the basis of its subdichotomous branching, possession of a prostrate system and the of a prostrate system and the production of polysporangia. It differs from the other genera of the tribe in the production of 2-celled propagules. Observation on the germination of the "monosporangia" of Mazoyerella arachnoidea and Monosporus spp. Indicate that they are analagous to the propagules of Deucalion and Anisoschizus. The mature of these propagules and their role in recycling the parent plant are discussed and contrasted with true monosporangia It is recommended that Monosporus be maintained as a from genus containing representalives from more than one tribe, as exemplified by plants from Lord Howe I, provisionally identified as M. indicus Boergesen which have both prostrate and erect, as opposed to only erect, axes. [ABSTRACT FROM AUTHOR]

Cubiculosporum koronicarpis Kraft (Cubiculosporaceae, Gigartinales), known previously only from the type locality (southeastern Luzon, Philippines), has been collected at North West Island on the southern Great Barrier Reef. The habitat, distribution and taxonomic status of the species are discussed, and habit features of the new specimens are illustrated. [ABSTRACT FROM AUTHOR]

The taxonomic position of Pyxidicula compressa, currently the nomenclatural basionym of two unrelated taxa (a diatom and a dinoflagellate), is clarified. Evidence is presented that the protologue of the species clearly represents a diatom, which is then correctly known as Tryblionella compressa. In the absence of original specimens, the species is lectotypified with illustrations from the protologue. It is proposed that the name Prorocentrum bidens be adopted for the dinoflagellate presently known as Prorocentrum compressum. [ABSTRACT FROM AUTHOR]

This special issue was initially conceived during a council meeting of the International Phycological Society in 2021, where the promotion of manuscript submissions focusing on regional research activities was suggested. The idea of a special issue on species diversity and ecology of calcified seaweeds from the Western Pacific Ocean, with topics related to warming and ocean acidification, was raised to complement a planned forum of the Asian Pacific Phycology Association to be held in Hokkaido. This special issue includes papers on species diversity and distribution of several coralline genera (Crustaphytum/Mesophyllum, Jania, Phymatolithon, Sporolithon), calcification, reproductive phenology, and responses to environmental factors (e.g. temperature, ocean acidification, nutrients, water flow) that are influencing the growth of coralline algae and shaping their community composition. [ABSTRACT FROM AUTHOR]

Abstract: Aim: Biogeographical processes underlying Indo‐Pacific biodiversity patterns have been relatively well studied in marine shallow water invertebrates and fishes, but have been explored much less extensively in seaweeds, despite these organisms often displaying markedly different patterns. Using the marine red alga Portieria as a model, we aim to gain understanding of the evolutionary processes generating seaweed biogeographical patterns. Our results will be evaluated and compared with known patterns and processes in animals. Location: Indo‐Pacific marine region. Methods: Species diversity estimates were inferred using DNA‐based species delimitation methods. Historical biogeographical patterns were inferred based on a six‐gene time‐calibrated phylogeny, distribution data of 802 specimens, and probabilistic modelling of geographical range evolution. The importance of geographical isolation for speciation was further evaluated by population genetic analyses at the intraspecific level. Results: We delimited 92 candidate species, most with restricted distributions, suggesting low dispersal capacity. Highest species diversity was found in the Indo‐Malay Archipelago (IMA). Our phylogeny indicates that Portieria originated during the late Cretaceous in the area that is now the Central Indo‐Pacific. The biogeographical history of Portieria includes repeated dispersal events to peripheral regions, followed by long‐term persistence and diversification of lineages within those regions, and limited dispersal back to the IMA. Main conclusions: Our results suggest that the long geological history of the IMA played an important role in shaping Portieria diversity. High species richness in the IMA resulted from a combination of speciation at small spatial scales, possibly as a result of increased regional habitat diversity from the Eocene onwards, and species accumulation via dispersal and/or island integration through tectonic movement. Our results are consistent with the biodiversity feedback model, in which biodiversity hotspots act as both “centres of origin” and “centres of accumulation,” and corroborate previous findings for invertebrates and fish that there is no single unifying model explaining the biological diversity within the IMA. [ABSTRACT FROM AUTHOR]

The characteristics of detached macroalgae (drift) in nearby highly eutrophic and mesotrophic estuaries in south-western Australia are compared to elucidate the magnitude and types of changes that occur in macroalgal drift when estuaries receive excessive nutrient input. Drift characteristics in the large basins of the microtidal, eutrophic Peel-Harvey and mesotrophic Swan-Canning, which is not subjected to large nutrient inputs directly from agricultural land, differed markedly. Biomass (dry weight) in mesotrophic estuary was dominated by rhodophytes (92%), particularly Laurencia and Hypnea, and in eutrophic estuary by opportunistic chlorophytes (68%), especially Chaetomorpha and Ulva. Prevalence and biomass of drift were far greater in the eutrophic estuary, particularly during summer and autumn when macroalgal growth rose sharply. Macroalgal biomass in the eutrophic estuary was positively related to salinity. These results facilitate predictions of how climatic and other anthropogenic changes influence extent of macroalgal growth and thus change the estuarine environment., (Copyright © 2021. Published by Elsevier Ltd.)