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In the present paper, Dictyota hauckiana is reported for the first time from Vietnam. It was found growing with other marine macroalgae nearshore, at 1–2 m depth in Ninh Hai waters, Ninh Thuan province. Morphological observations and phylogenetic analysis based on the concatenated rbcL and psbA are presented. There are now 13 species of Dictyota known from Vietnamese waters. [ABSTRACT FROM AUTHOR]

Knowledge of life cycle progression and reproduction of seaweeds transcends pure academic interest. Successful and sustainable seaweed exploitation and domestication will indeed require excellent control of the factors controlling growth and reproduction. The relative dominance of the ploidy-phases and their respective morphologies, however, display tremendous diversity. Consequently, the ecological and endogenous factors controlling life cycles are likely to be equally varied. A vast number of research papers addressing theoretical, ecological and physiological aspects of reproduction have been published over the years. Here, we review the current knowledge on reproductive strategies, trade-offs of reproductive effort in natural populations, and the environmental and endogenous factors controlling reproduction. Given that the majority of ecophysiological studies predate the "-omics" era, we examine the extent to which this knowledge of reproduction has been, or can be, applied to further our knowledge of life cycle control in seaweeds. [ABSTRACT FROM AUTHOR]

Classification of the red algae (Rhodoplantae) has undergone significant change since the seminal work of Harald Kylin, “ Die Gattungen der Rhodophyceen,” a half century ago. The number of genera has nearly doubled over this time period, at least in part due to recent molecular comparative work. Information gleaned from gene-sequencing analyses has resulted in a red algal classification that reflects a more accurate phylogenetic framework than that based solely on morphological data. This paper tabulates the known 834 genera of red algae today with taxonomic synonyms and literature references reflecting the great change over fifty years. [ABSTRACT FROM AUTHOR]

Despite numerous recent studies on the Gelidiales, most taxa belonging to this order are still difficult to distinguish when in the vegetative or tetrasporic state. This paper describes in detail the morphological and ontogenetic features of the prostrate system of the order with the aim of validating its diagnostic and taxonomic significance. Observations were made on fresh, liquid preserved and cultured thalli. The morphology of the attachment system and the characteristics of rhizoid ontogeny have proven to be useful diagnostic and taxonomic characters. Species belonging to Gelidium, Pterocladia and Pterocladiella bear true attachment organs consisting of cells of both exogenous and endogenous origin. In the family Gelidiellaceae, in contrast, attachment to the substratum is effected by single independent exogenous rhizoids. The attachment rhizoids of the Gelidiales, both exogenous and endogenous, are of the same cell type, and are the so-called hyphae, historically considered typical of the family Gelidiaceae only. A new subdivision of the Gelidiales into three families is proposed here, with the amendment of both Gelidiellaceae and Gelidiaceae, and the Pterocladiaceae fam. nov. [ABSTRACT FROM AUTHOR]

A detailed vegetative and reproductive study of the little known species Spatoglossum solieri, using both fresh material and herbarium specimens, showed that the reproductive structures hitherto described as oogonia in S. solieri correspond, in fact, to undivided sporangia. Oogonia of S. solieri are reported and described for the first time in the present paper. They can be distinguished from undivided sporangia by their shape, the presence of a pedicel consisting of 1-2(3) basal flat cells and because they protrude up to half their length above the blade surface. Sporangia appeared as sessile structures, although they sometimes show a single lenticular stalk cell laterally placed. Likewise, and contrary to the published data, this study showed that antheridia are pedicellate structures. [ABSTRACT FROM AUTHOR]

Species of the dinoflagellate genus Alexandrium are marine and planktonic forms, widely distributed, and some are recognized to form harmful algal blooms and to produce saxitoxins causing Paralytic Shellfish Poisoning in humans, and other toxins. We studied the species composition of Alexandrium in tropical and subtropical coastal areas of the Mexican Pacific: from the southern Gulf of California to the Gulf of Tehuantepec. Eleven Alexandrium species were identified, described, and illustrated using light microscopy, and occasionally scanning electron microscopy for certain species. Additionally, the genetic characterization of seven strains and four species, was performed, using sequences of the D1/D2 LSU rDNA and ITS regions. We identified the species (morphospecies): Alexandrium affine, A. gaarderae, A. globosum, A. leei, A. margalefii, A. minutum, A. monilatum, A. pseudogonyaulax, A. tamarense, A. tamiyavanichii, and A. tropicale. Of these, A. affine, A. leei, A. minutum, A. monilatum, A. pseudogonyaulax, A. tamarense and A. tamiyavanichii have been widely recognized as harmful algae. Alexandrium gaarderae, A. globosum and A. tropicale are new records for the Mexican Pacific. This is the first morphological documentation of A. pseudogonyaulax. Future studies of the genus might increase its species richness if more cultures are established and metabarcoding approach is used. [ABSTRACT FROM AUTHOR]

Mastogloia frickei Hustedt was found in Guam and studied with scanning electron microscopy. A species known by that name in Florida/Bahamas is shown to be a different species and is described as Mastogloia floridensis sp. nov. Both have alveolate striae, which is unusual in the genus. A third alveolate species was present in Florida samples and had been misidentified previously. It is described as Mastogloia lucayensis sp. nov. Ultrastructure observations of these species expand the diversity of alveolate stria morphology. [ABSTRACT FROM AUTHOR]

Morphological variability is common among macroalgae. In central Chile, Mazzaella laminarioides extends throughout the intertidal rocky zones, where blades are reported to grow up to 20 cm in length. Nevertheless, in low rocky intertidal zones with sand-influence, blades are noticeably larger than in other shores without sand effect. The aim of this study was to compare the morphology of M. laminarioides blades from two different conditions. Blades collected from four sites with, and four without, sand-influence were evaluated with traditional morphometry. Results showed that blades were longer and wider in sand-influenced sites. Sand abrasion was not directly evaluated, but indirect effects such as the abundance of bare rock and of sand tolerant species were higher in areas with sand-influence. Also, long blades were restricted to sand-influenced sites, supporting the relation between these two variables. Molecular analyses using the COI marker confirmed large-bladed individuals as M. laminarioides. Results indicated that life cycle phase, seasonality and vertical height were not related to large blades. We suggest that restriction of large blades to sand-influenced sites may be related to the healing processes of basal holdfasts after suffering sand abrasion. [ABSTRACT FROM AUTHOR]

Skeletonema species are among the most important components of phytoplankton communities in the temperate and tropical Pacific Ocean. Data on Skeletonema species diversity and abundance in the northeastern Pacific are fragmentary. The long-term observations (1996–2019) of the phytoplankton from the coastal waters of the northwestern Sea of Japan resulted in five Skeletonema species being recorded: Skeletonema costatum, S. dohrnii, S. japonicum, S. marinoi and S. menzelii. For each of the species, a morphological description is provided based on electron microscopy. Ecological factors influencing the distribution of the species and their occurrence under certain environmental parameters are discussed. One of the species, S. menzelii, is a new record for Russia. Skeletonema costatum was confirmed to occur in the study area. Seasonal and interannual changes in the abundance of Skeletonema species were studied. The concentrations of the species varied from 20 cells l−1 to 12,700,000 cells l−1. From 1996 to 2018 there was a downward trend in the numbers of Skeletonema. Skeletonema japonicum was noted for the first time to bloom. Skeletonema dohrnii formed summer blooms; S. japonicum bloomed in the autumn. No Skeletonema blooms were detected in the winter months. [ABSTRACT FROM AUTHOR]

It was noted that Mediterranean specimens collected at different stations from around Sicily, Italy and referred to as Laurencia dendroidea (as Laurencia majuscula) were similar to the recently described species Laurenciella marilzae. Presented in this study are the results of an integrative approach using both morphology and molecular data (COI-5P + rbcL) to establish which taxon these specimens should be referred to. Molecular analyses show these specimens belong to Laurenciella, and strongly suggest they are within the species L. marilzae. Morphological examinations of these Mediterranean specimens were also detailed and found to support the conclusion that they belong to L. marilzae. [ABSTRACT FROM AUTHOR]

The morphology of the crustose brown alga Hapalospongidion gelatinosum is described in detail based on specimens collected on the Mexican tropical Pacific coast. Molecular phylogenetic analysis of DNA sequences of chloroplast-encoded RuBisCo large subunit (rbcL) and mitochondrial-encoded cytochrome c oxidase subunit 1 (Cox-1) genes, reveals that our samples form a newly recognized clade distinct and distant from the clades of other families in Ralfsiales. Contrary to the previously proposed synonymy between Hapalospongidion and Mesospora, we conclude that both are distinct genera. We also provide a different interpretation of a diagnostic character that allows a distinction of Basispora from the latter two genera. We propose the erection of the new family Hapalospongidiaceae to accommodate the sole genus Hapalospongidion. A Lectotype and an Epitype for H. gelatinosum are designated. [ABSTRACT FROM AUTHOR]

Studies of the taxonomy and diversity of flattened Gracilaria species which occur commonly in coastal areas of Thailand are few and underestimate species richness. Recently, flattened Gracilaria plants were collected along the west coast of southern Thailand (Andaman Sea). We describe a new flattened Gracilaria species, Gracilaria coppejansii Muangmai, Lewmanomont, Prathep, Terada et Zuccarello sp. nov., from Phuket Island on the basis of comparative morphology and rbcL sequence analyses of these samples. The new species is mainly characterized by thalli with dichotomous branching, numerous proliferations on the blade margin of female gametophytes, textorii-type spermatangial conceptacles and a few nutritive filamentous cells in mature cystocarps. Morphologically, G. coppejansii most closely resembles Gracilaria textorii but differs in some morpho-anatomical characteristics of the blade and female reproductive structures. rbcL sequence analyses also clearly demonstrated that G. coppejansii was genetically distinct from other flat Gracilaria species. Gracilaria coppejansii was phylogenetically positioned close to Gracilaria lantaensis, a recently described flattened species also on the west coast of Thailand. [ABSTRACT FROM AUTHOR]

Fungi have evolved mechanisms to function in the harsh conditions of the Arctic Ocean and its adjacent seas. Despite the ecological and industrial potential of these fungi and the unique species discovered in the cold seas, Arctic marine fungi remain poorly characterised, with only 33 publications available to date. In this review, we present a list of 100 morphologically identified species of marine fungi detected in the Arctic. Independent molecular studies, applying Sanger or high-throughput sequencing (HTS), have detected hundreds of fungal operational taxonomic units (OTUs) in single substrates, with no evidence for decreased richness of marine fungi towards northern latitudes. The dominant fungal phyla may be substrate-specific, as sea-ice and seawater seem to host more Chytridiomycota and Basidiomycota than Ascomycota- dominated driftwood and sediments. Molecular studies have revealed the presence of the Chytridiomycota and Leotiomycetes in Arctic waters, with mounting evidence suggesting a significant role in nutrient and carbon cycling. The high detection frequency of Leotiomycetes is partly due to OTUs from marine Cadophora (Helotiales) that are indistinct from terrestrial strains. Knowledge of Arctic marine fungi has rapidly increased in recent years. Nevertheless, some bottlenecks, such as limited OTU identification persist and more researchers are encouraged to join the study of Arctic marine fungi. [ABSTRACT FROM AUTHOR]

Sexual dimorphism on a macroscopic scale is unusual within the Phaeophyceae. We report for the first time macroscopic sexual dimorphism in Fucus radicans. A set of morphological characters was measured on three dioecious Fucus species, F. radicans, Fucus serratus and Fucus vesiculosus, to determine if sexual dimorphism occurs in the endemic F. radicans in the Baltic Sea and if it also is found in the other fucoids. F. radicans was sampled from highly clonal populations of the Bothnian Sea and from populations in the Väinameri Sea where no clones have been found. In both locations, sexual dimorphism was recorded in receptacle size and weight in F. radicans. Also, the receptacle dry weight to wet weight ratio was higher in males than in females, showing that male receptacles have a lower water content than females. The dimorphism was more pronounced in the Bothnian Sea populations, where further differences between the sexes in thallus width and fertility index also were present. This has not been shown for any member of the genus Fucus before, but seems to be a species-specific character in F. radicans, as there were no differences between the sexes in either F. serratus or F. vesiculosus. [ABSTRACT FROM AUTHOR]

A unicellular marine diatom, Entomoneis sp. MMOGRB 0374S, was isolated as a candidate strain for high production of a polyunsaturated fatty acid (PUFA), arachidonic acid (ARA, 20:4ω6). Its morphological characters were typical for representatives of the genus Entomoneis, e.g. junction line, sigmoid keel and panduriform girdle view. This species was differentiated from other Entomoneis species by its smaller size and denser stria. Phylogenetically, it was distinct from other taxa with a long branch. This relationship was also emphasized by only 94% nucleotide similarity between Entomoneis sp. MMOGRB 0374S and other related species. The biomass concentration reached 182 mg l- 1 at the stationary phase and 229 mg l- 1 after 3 days of nitrogen-limited culture. Lipids were extracted using four methods, and the dichloromethane (DCM) /methanol method was the most effective, yielding 36% of dry biomass at the stationary phase and 40% after 3 days of nitrogen-free culture. Gas chromatography revealed 17 types of fatty acids. ARA was the major component of PUFA and represented between 16% and 19% of the total fatty acids using the four lipid extraction methods, among which DCM/methanol yielded the highest proportion of ARA. Considering the yields of both total lipids and ARA, the DCM/methanol method was the most effective for ARA extraction. [ABSTRACT FROM AUTHOR]

Species of Ulva are distributed worldwide in various aquatic habitats and their morphological characters change considerably in response to environmental conditions, which makes identification in this genus problematic. All Ulva species so far described from the Persian Gulf, Iran, have been identified by classical taxonomic methods. In this study, Ulva spp. collected from the Persian Gulf were identified by combined morphological and molecular methods. We sequenced the internal transcribed spacer ITS2 and the rbcL gene in 15 specimens, representing typical morphotypes of over 50 samples. Maximum likelihood, maximum parsimony and Bayesian inference (BI) phylogenetic reconstructions using ITS and rbcL revealed clades, which we identified as Ulva chaugulii, U. paschima and U. ohnoi. These three species have not been recorded from the Persian Gulf, Iran before. The morphology of U. chaugulii differed considerably from its species description, showing further evidence for extreme intraspecific variation in morphology in this cosmopolitan genus. [ABSTRACT FROM AUTHOR]

Laetinaevia marina is a frequent ascomycetous fungus that is widely distributed on the seashores of Scandinavia and Great Britain. It grows on fronds of Fucales (Phaeophyceae) that are washed ashore and lie decaying at the high tide mark or further up on the beach. It is one of the few described marine discomycetes. In the current generic concept it is regarded as a member of Naevioideae (Dermateaceae or Mollisiaceae), while it has previously been placed in the genus Orbilia (Orbiliaceae). We studied fresh collections, in live and dead state, to provide a morphological update on the species and to elucidate its systematic placement using molecular systematics. The hemiamyloid reaction of the apical ring, the absence of croziers, and the faintly refractive vacuolar bodies of the terminal cells of living paraphyses are reported here for the first time. A thin gel sheath surrounding the ascospores was confirmed to exist. Based on morphological characters, ribosomal RNA and protein coding gene sequences published for this species here for the first time, we show that L. marina is distinct from the genera and families it was previously placed in, and propose the new combination Calycina marina, despite its erumpent, sessile, pulvinate and rather immarginate apothecia. Furthermore, we present additional observations on the ecology, phenology, and distribution of the species. [ABSTRACT FROM AUTHOR]

The genus Neoralfsia was newly described by P.-E. Lim and Kawai on the basis of rbcL sequence data from specimens from Japan and Malaysia identified as Neoralfsia expansa, and N. expansa [ Myrionema (?) expansum] from Mexico was designated as the type species. Our maximum likelihood and Bayesian analyses show that specimens of N. expansa from the type locality are grouped into a new, not previously described, clade in Neoralfsiaceae, distant from that of the putative specimens attributed to N. expansa from Japan and Malaysia. We show that genuine ' expansa' does not include Asian material. The distribution of the species is not as wide as has been previously recorded. [ABSTRACT FROM AUTHOR]

The occurrence of Stenogramma interruptum in northeast Asian waters is a matter of debate. We analyzed rbcL from Korean specimens filed under the species name S. interruptum in combination with morphological observations. A partial rbcL sequence revealed that the Korean specimens were clearly distinct from other species of Stenogramma as well as S. interruptum from Europe. The morphology and anatomy of the Korean specimens were consistent with the rbcL data. Based on these results, we herein describe the new species Stenogramma guleopensis from Korea. Stenogramma guleopensis is distinguished mostly by its small size (up to 8 cm), slender thallus with narrow and parallel-sided segments, terminal branches basally constricted, two layers of cortical cells, two to three layers of medullary cells, and a gradient of two layers of smaller cells between the cortex and medulla. Further collections and careful examinations in the field will probably reveal extension of the distribution of S. guleopensis to the waters surrounding Korea. [ABSTRACT FROM AUTHOR]

We performed morphological and molecular studies of Laurencia catarinensis from the Canary Islands. This species has an entangled habit, cushion-like tuft formation, cortical cell walls, slightly to markedly projecting near the apex, and lacking lenticular thickenings in medullary cells. We inferred its phylogenetic position by analyzing the chloroplast-encoded rbc L gene sequences from 41 samples. The results demonstrate that specimens of L. catarinensis from the Canary Islands, where it is referred to as L. intricata, and those from Brazil (including specimens from the type locality in Santa Catarina) form a monophyletic clade with low genetic divergence (0-0.9%). In contrast, specimens of L. intricata from the type locality in Cuba, Mexico, and the USA were clearly distinct from L. catarinensis collected in Brazil and the Canary Islands, as shown by high genetic divergence values (4.9-5.7%). The type material of L. catarinensis from Brazil allowed us to identify all samples from the Canarian Archipelago as L. catarinensis. These findings expand the known geographical distribution of L. catarinensis to the eastern Atlantic Ocean and demonstrate an amphi-Atlantic distribution of the species. [ABSTRACT FROM AUTHOR]

Laurencia caduciramulosa and L. minuscula (Ceramiales, Rhodophyta) are reported for the first time from the Cuban archipelago based on materials collected from the northwestern coast of Cuba (Havana and Rincón de Guanabo). The specimens of these two species, both characterized by a markedly reduced size, were collected twice, in April 2006 and June 2007, growing epiphytically on Thalassia testudinum. In the present study, the morphological characters of both species are described, and the geographical distribution of L. caduciramulosa is expanded to the Caribbean Sea and to the northwestern Atlantic Ocean. [ABSTRACT FROM AUTHOR]

Prorocentrum minimum (Dinophyceae), a planktonic microalga forming red tides, is considered a potentially toxic species. In view of its likely harmful role, accurate identification of P. minimum to species and/or subspecies may be particularly important. Like most thecate dinoflagellates, species identification is largely based on morphology of the theca and on features of both flagellar and auxiliary apical pores. In this study, we compared 18S rDNA gene sequences to confirm that P. minimum strains isolated from the Baltic (3 strains) and Adriatic (3 strains) Seas were the same species, and compared the morphology of the apical pore region among the strains. Our results confirm that the platelet arrangement in the apical pore region is a stable morphological character, independent of the strain origin and culture growth phase. In addition a small tooth, opposite to the apical collar in the auxiliary pore area, is proposed as an additional diagnostic character. [ABSTRACT FROM AUTHOR]

Preliminary studies on dinoflagellates epiphytic on macrophytes in a bight of Peter the Great Bay, Sea of Japan revealed the presence of two species of the genus Ostreopsis, O. cf. ovata and O. cf . siamensis. Morphometric features, such as the length of the pore plate, and thecal ornamentations were used for species identification. The two species differed from each other in cell size and the length of the pore plate. Cells of O. cf. ovata were smaller in length and width, with a dorsoventral diameter of 36–60 μm and a width of 24–45 μm, in comparison with the cells of O. cf. siamensis, which were 63–78 μm in dorsoventral diameter and 36–54 μm in width. Cells of O. cf. siamensis are slightly flattened in comparison with O. cf. ovata; the dorsoventral to anteroposterior diameter ratio varied from 1.9 to 2.7 for O. cf. ovata and from 1.8 to 3.5 for O. cf. siamensis. The length of the pore plate in O. cf. ovata (6.3–8.3 μm) is shorter than that in O. cf. siamensis (11–13 μm), while the diameter of the thecal pores in O. cf. ovata and O. cf. siamensis overlapped markedly (0.12–0.25 μm and 0.16–0.20 μm, respectively). The two species were present from August to October at water temperatures of 7–25°C on almost all macrophytes collected. The maximum abundance of Ostreopsis spp. reached 10,970 cells g-1 dry weight in late September at a water temperature of 9°C. This is the first occurrence of the genus Ostreopsis in Russian waters, which are characterized by cold temperatures during the winter season. [ABSTRACT FROM AUTHOR]

Gracilaria “ verrucosa” is now regarded an invalid name, with G. gracilis being used in recent studies of the genus from the Russian coast of the East Sea (Sea of Japan). This has created nomenclatural confusion for members of the genus in this region. Here we revise the taxonomy of G. “ verrucosa” from Peter the Great Bay (East Sea, Russia) based on morpho-anatomical characters and comparisons of nuclear small subunit rDNA, plastid rbcL and mitochondrial cox1 sequence data. No differences were found between sequences for attached and unattached forms of G. “ verrucosa”. Molecular data also indicate that G. “ verrucosa” from Peter the Great Bay is conspecific with Gracilaria vermiculophylla from the northwestern Pacific, and the Russian population is closely related to Korean-Japanese populations from the East Sea rather than with populations on the Pacific coast of Japan. [ABSTRACT FROM AUTHOR]

Erythroglossum lusitanicum was originally described from sterile and tetrasporophytic material. The apical organization and the sexual structures have considerable relevance for classification of Delesseriaceae, and these are described here for the first time in this species. The range of morphological variability in some species of the genus Erythroglossum in Atlantic Europe has been broadened, requiring a revision of the taxonomic identity of E. lusitanicum. Reproductive characters observed in E. lusitanicum include: 1) procarps scattered over the blade surface and composed of a supporting cell bearing two 4-celled carpogonial branches and a single group of sterile cells; 2) carposporangia formed in chains; and 3) spermatangial sori consisting of two layers of spermatangial mother cells bearing spermatangia. These features, together with the Phycodrys-type apical organization, are in accordance with those described for the genus Erythroglossum. The main taxonomic features of E. lusitanicum that distinguish it from congeners in Atlantic Europe are thallus growth that occurs in each blade by means of a single apical cell located in the tip, and its turf forming habit. [ABSTRACT FROM AUTHOR]

The original description of Halymenia actinophysa was based on few thalli and limited characteristics. Moreover, later descriptions seem to have included more than one species; the confusion of identity was exacerbated by the lack of carposporangial material. From 1995 to 2006, extensive collections of this species were made at several locations (including the type locality) in the southwestern part of the Gulf of California. The study focused on gametangial material. Our aim was to analyze the morphology and anatomy of this species (based on vegetative and reproductive features) to better understand species discrimination. Halymenia actinophysa is a foliose alga with orbiculate to elliptical ruffled blades and a gelatinous, membranous, slippery frond texture. In transverse section, the blade has a thickness of 150–300 μm, a cortex with one or two rounded or elongated cells and an internal layer with elongated, stellate cells connected to the anticlinal filaments of the medulla. Reproductive anatomy is in agreement with the modern concept of the genus and supports the concept that earlier descriptions comprised a mixture of species. The present study strongly suggests the need for a formal review of the genus Halymenia in the Gulf of California to delimit the species and to relate them to other genera of the same family. [ABSTRACT FROM AUTHOR]

Thirteen species of benthic marine algae are reported as new to the mid Atlantic Azores archipelago, and the status is confirmed for five other species. Some of the new records fall within their overall distributional range. The discovery of seven species ( Codium taylorii, Digenea simplex, Gelidiella tinerfensis, Gelidiopsis intricata, Laurencia microcladia, Papenfussiella kuromo, Phyllophora gelidioides) represents a northern extension in their Atlantic distributional range. The archipelago is the western limit of Papenfussiella kuromo and Phyllophora gelidioides in the Atlantic Ocean. Ascophyllum nodosum, common as drift, was found for the first time attached to rocks on Graciosa Island and Caulerpa webbiana is confirmed as a recent immigrant to the archipelago. Four species are removed from the flora. [ABSTRACT FROM AUTHOR]

In a recent review of the seagrass genus Halophila in Japan, eight taxa including four new species were listed: (i) H. decipiens, (ii) H. minor, (iii) H. major, (iv) H. ovalis, (v) H. mikii, (vi) H. nipponica, (vii) H. okinawensis, and (viii) H. gaudichaudii. In this study, the specific concept of Halophila in Japan as well as some other geographic areas was re-assessed by a combination of nuclear ribosomal ITS1, 5.8S rDNA, and ITS2 sequence analyses and morphological examinations of both recently collected materials and available type collections. The results confirm the distinctness of the Australian endemic species H. australis and the putative pan-tropical taxon H. decipiens; but also demonstrate conspecificity of: (i) H. minor and H. ovalis; (ii) H. major and H. mikii; and (iii) H. nipponica, H. okinawensis and H. gaudichaudii. As an outcome of this study, we recommend restricting the list of Halophila representatives in Japan to the following four species: (i) H. decipiens, (ii) H. major, (iii) H. ovalis, and (iv) H. nipponica. In addition, we predict the possibility of H. major occurring further south than currently recorded. [ABSTRACT FROM AUTHOR]

Molecular studies were carried out on Chondrophycus gemmiferus and C. poiteaui (Rhodomelaceae) from the Mexican Caribbean Sea. These species are morphologically related, but differ mainly in the presence of the apiculate projection of epidermal cells near the apices of branches. Both species belong to Chondrophycus, as indicated by the presence of two periaxial cells per axial segment and a 90° arrangement of tetrasporangia, but share characteristics with Laurencia species (e.g., presence of secondary pit connections between adjacent epidermal cells). The phylogenetic position of these species was inferred by an analysis of chloroplast-encoded rbcL gene sequences of 21 taxa, using two members of the Rhodomelaceae and two of the Ceramiaceae as outgroups. The results corroborate the taxonomy of the Laurencia complex, which comprises the genera Laurencia, Chondrophycus and Osmundea, and indicate that rbcL provides an adequate phylogenetic signal to study the intergeneric and interspecific relationships within the complex. In spite of this, relationships within the clade formed by C. gemmiferus and C. poiteaui were not resolved by any analysis because of the low level of genetic variation between their rbcL sequences (0.01–0.02%). On the basis of both molecular data and morphological similarities, we concluded that C. gemmiferus should be considered as a variety of C. poiteaui and the following new combination is proposed: Chondrophycus poiteaui var. gemmiferus (Harvey) comb . et stat. nov. [ABSTRACT FROM AUTHOR]

Four species of marine algae are reported from the Canary Islands for the first time. Our report of the western Atlantic Gelidiella setacea (Gelidiales, Rhodophyta) is the first from the eastern Atlantic Ocean. Pseudotetraspora marina (Tetrasporales, Chlorophyta) previously known on the eastern side of the Atlantic Ocean from temperate saltmarshes only, is now reported growing in the shallow sublittoral zone, the habitat in which tropical western Atlantic populations also occur. The presence of Lomentaria chylocladiella (Rhodymeniales, Rhodophyta) represents the first report in the Atlantic Ocean of a species previously thought to be endemic to the Mediterranean Sea. The record of the widely distributed Acrochaetium hallandicum (Acrochaetiales, Rhodophyta) was not unexpected. Specimens of A. hallandicum have vegetative cells with a single lobate parietal chloroplast with a single pyrenoid, a feature that among acrochaetioid algae occurs exclusively in the genus Colaconema (Colaconematales), and consequently the species is transferred to this genus. Fertile sporophytes are described for Gelidiella setacea, a species previously known only in its vegetative condition. Cruciately to irregularly divided sporangia are regularly arranged in transverse rows in stichidia laterally formed on the axes. The species is transferred to the genus Parviphycus on the basis of the morphology of the stichidia and the distichous pattern of apical division exhibited by the axes, both exclusive features of this genus. [ABSTRACT FROM AUTHOR]

Rhodoliths are unattached calcareous red algae that form extensive beds. Although rhodolith beds are widely distributed in temperate and tropical areas, a recent discovery in the North Pacific Ocean represents a significant northward extension of known rhodolith distribution. This bed, located in Prince William Sound, Alaska, is composed of one rhodolith species, Phymatolithon calcareum, with two reproductive states, tetrasporangial and gametangial. A characteristic feature of this bed is that cryptofaunal chitons were the most abundant associated invertebrate species. Comparisons with P. calcareum populations in other regions showed that Prince William Sound thalli are smaller in many measurable anatomical features. [ABSTRACT FROM AUTHOR]

Reproductive morphology of the Mediterranean red alga Kallymenia patens is described for the first time, confirming its position in the genus. K. patens is characterized by a non-procarpic female reproductive apparatus, carpogonial branch systems consisting of supporting cells bearing both three-celled carpogonial branches and subsidiary cells that lack a hypogynous cell and carpogonium; fusion cells develop numerous connecting filaments, and tetrasporangia are scattered over the thallus and are probably cruciately divided. Old fertile spathulate specimens of K. patens are morphologically similar to K. spathulata, but they can be distinguished by the length of spathulated proliferations (up to 0.6 cm and 6 cm, respectively), the length of inner cortical cells (up to 70 and 30 μm, respectively), and the gonimoblast location (in proliferations from the perennial part of the blade and over all the thallus surface, respectively). [ABSTRACT FROM AUTHOR]

Since the first collection in 1989 from Mahone Bay (Nova Scotia), the highly invasive green macroalga Codium fragile has been spreading in Atlantic Canada and has become established along the coasts of Nova Scotia, Prince Edward Island and New Brunswick. Considerable morphological variation had been found among thalli from different collection sites. This variation may be caused by the presence of different subspecies, or by phenotypic plasticity of one of the subspecies. Morphometric and molecular investigations were performed on Codium collected from seven sites in Maritime Canada and one from Maine to evaluate these hypotheses. Based on both mucron length and ISSR markers, thalli separated into three groups, suggesting multiple introductions of C. fragile into Canada. A group from the eastern shore of Nova Scotia and the coast of New Brunswick is clearly ssp. tomentosoides that likely originates from the United States. A second group, growing in Malpeque Bay in Prince Edward Island, is possibly an asexual variant of ssp. atlanticum, another invasive subspecies of C. fragile. A third group, found in Caribou Harbour only, is an intermediate in terms of both mucron length and molecular data, suggesting a hybrid of ssp. tomentosoides and ssp. atlanticum. The origin of this intermediate group remains to be established. [ABSTRACT FROM AUTHOR]

Thirteen species of benthic marine algae are reported new for the isolated mid-Atlantic Azores archipelago and five older records are confirmed. Seven ( Bangia atropurpurea, Codium fragile spp. tomentosoides, Ectocarpus fasciculatus, E. siliculosus, Porphyrostromium ciliare, Ulothrix flacca and Ulvaria oxysperma) are widespread amphi-Atlantic species some of which extend in distributional range south to the Canary Islands. Cryptonemia seminervis, Ctenosiphonia hypnoides and Phyllophora sicula are known from the northeastern Atlantic Ocean only and also occur in the Canary Islands. The Azores archipelago is the western limit of distribution of Codium fragile ssp. atlanticum, Bostrychia scorpioides, Bryopsis cupressina, Erythroglossum laciniatum, Haliptilon squamatum and Phyllophora sicula, and the southern limit of C. fragile ssp. atlanticum and E. laciniatum. The tropical species Phyllodictyon anastomosans, Valonia macrophysa and Wurdemannia miniata reach their northern limit of distribution there. Asparagopsis taxiformis is now less common possibly due to competition with the non-native A. armata; subspecies of the non-native C. fragile now occur widely in the Azores. The status of Fucus vesiculosus, Ulva ( Enteromorpha) clathrata and Rhizoclonium tortuosum is clarified and other species have been removed from the flora. The continuing addition of new species records for the Azores shows the archipelago to be floristically richer than other Atlantic islands except for the Canary Islands. [ABSTRACT FROM AUTHOR]

Hormosira banksii is a morphologically variable macro-algal species from southeastern and southern Australia, which has been previously categorised into ecoforms according to habitat. This study is by far the largest quantitative evaluation of morphological variation in H. banksii, covering 74 sites from South Australia, Victoria, New South Wales and Tasmania. Morphological features from 505 samples were analysed using principal components analysis, with the patterns identified being statistically assessed with a Monte Carlo permutation test. There was considerable morphological variation between samples taken at several marine (but not estuarine) sites in both 1994 and 1999. However, this variation was not consistent across either morphological features or populations, and presumably represents random fluctuations. Analysis of the entire dataset demonstrated a significant difference between samples growing in marine and estuarine habitats. Further assessment of variation within these two groups revealed some significantly different populations based on geographical locations but not habitat variation. While this study presents strong evidence for two distinct taxa within H. banksii (marine versus estuarine populations), the taxonomic status of this species should not be altered until genetic studies have been conducted. [ABSTRACT FROM AUTHOR]

Sargassum kendrickii N. Goldberg et Huisman, sp. nov. is described from subtidal habitats in the Esperance region, southern Western Australia. The new species belongs to the subgenus Phyllotrichia and can be distinguished from all previously described species in the morphology of its lateral branches, which are pinnate, alternately arranged, and have serrated margins. Vesicles are absent and receptacles form open clusters in branch axils. The new species is compared to all species of Sargassum subgenus Phyllotrichia worldwide. [ABSTRACT FROM AUTHOR]

Hypnea cornuta, a species previously introduced into the eastern Mediterranean Sea, has been discovered recently in the Mar Piccolo of Taranto (southern Italy). The specimens are in good agreement with Indo-Pacific descriptions and reference material. It is highly probable that H. cornuta has been introduced either from eastern Mediterranean or Indo-Pacific populations via ship traffic or shellfish transfers (mussels). Since being introduced, H. cornuta has given rise to a stable both attached and freefloating population throughout the Mar Piccolo. Both attached and unattached plants are described. Field and culture observations have confirmed the reproductive role of the stellate branchlets as propagules. Vegetative reproduction both by propagules and fragmentation seems to be the only mode of reproduction in the Mar Piccolo. [ABSTRACT FROM AUTHOR]

Phytoplankton samples were collected along the north coast of the Antarctic peninsula, the Weddell Sea and the Gerlache Strait, in different seasons in 1985, 1986, 1999, and 2000-2002. Chaetoceros castracanei Karsten, a fairly rare species was present in the samples; its morphology, taxonomy and distribution have not been recently investigated. This species occurred mainly from January to April, and was recorded with relatively high abundances in the Weddell Sea (up to 9.5×104 cells I1). C. castracanei forms straight or slightly curved, short to long chains, with the terminal and intercalary setae pointing in the same direction. The apertures are very reduced, centrally constricted, and there are numerous chloroplasts in the cells including the setae. Electron microscopy studies showed that valves are randomly perforated by round poroids, costae on the valve are absent, and an excentric rimoportula is present in every valve of the chain; the setae are circular in cross section at the base, but become four-sided distally. Setae have perpendicular rows of elongate poroids, spines are arranged in spirals along the setae and the tips are very pointed. The intercalary setae are fused together in sibling valves. Chaetoceros impressus Jensen et Moestrup, recently described from Danish waters, appears to be conspecific with C. castracanei, and consequently we propose it as a synonym of the latter. The known distribution of Chaetoceros castracanci may be broadened to include Antarctic, subantarctic and Danish waters, and also possibly more temperate regions. [ABSTRACT FROM AUTHOR]

The new marine nanoplanktonic diatom, Thalassiosira fryxelliae, is described with light and scanning electron microscopy from material collected in Argentinian coastal waters. T. fryxelliae is a morphologically distinctive species with: 1) cells embedded in irregular gelatinous masses, 2) absence of central, sub-central and scattered strutted processes on the valve surface, 3) one marginal ring of strutted processes with external tubes, 4) one marginal labiate process included in the ring of the strutted processes, 5) areolation pattern variable linear, sublinear, eccentric or irregular. Externally, the marginal strutted processes have double tubes, at least in the distal part, cut distally and with the half-cylinder bent vertically with crenulated distal edges and the labiate process has a simple tube. Internally, the strutted processes are short with four operculate satellite pores and the labiate process is sessile and radially located. Thaiassiosira fryxelliae is similar to T. angulata and T. nanolineata in morphology and distribution pattern of the marginal strutted processes and in the location of the labiate process and to T. leptopus and some specimens of T. guillardii and T. pseudonana in lacking one central strutted process. [ABSTRACT FROM AUTHOR]

We investigated a collection of Nemastoma J. Agardh, nom. cons. (Nemastomatales, Rhodophyta), including the Mediterranean type material of species described by J. Agardh, Kützing and Ercegovic, and recent specimens from the Mediterranean Sea, Adriatic Sea and northeastern Atlantic Ocean. Based on their habit and vegetative and reproductive structures, we confirm that: (i) all the Mediterranean specimens studied belong to the genus Nemastoma; (ii) two species of Nemastoma co-exist in the Mediterranean Sea: (a) N. dichotomum, which is characterized by great plasticity of habit, a cartilaginous thallus in its basal and middle parts, and presumed reproduction exclusively by apomixis; and (b) N. dumontioides, which is characterized by a regularly pseudodichotomous, saccate-membranous thallus, and which reproduces both sexually and probably apomictically; and (iii) the Atlantic specimens attributed to N. dichoto- mum belong to other genera, and so, N. dichotomum is probably endemic to the Mediterranean Sea. Thus, three species described by Kützing have been reduced to varieties of Nemastoma dichotomum: (a) var. biasolettianum (Kützing) Rodríguez-Prieto, Verlaque et Vergés comb. nov. et stat. nov., with ligulate upper parts, (b) var. caulescens (Kützing) Rodríguez-Prieto, Verlaque et Vergés comb. nov. et stat. nov., with wedge-shaped upper parts, and (c) var. incrassatum (Kützing) Rodríguez-Prieto, Verlaque et Vergés comb. nov. et stat. nov., with spathulate upper parts. Finally, Nemastoma constrictum and N. con- strictum var. longitrichogynum are placed in synonymy with N. dichotomum var. caulescens. [ABSTRACT FROM AUTHOR]

Prorocentrum minimum (Dinophyceae) is a red tide­forming toxin­producing planktonic microalga from coastal waters worldwide. In this study, the morphology of natural and cultured populations of P. minimum was examined to investigate whether the species can be split morphologically into more species. The diacritical features of cell shape and size, ornamentation of thecal plates, and architecture of the apical pore area and intercalary band were studied from scanning and light micrographs. Cell size of P. minimum is similar in Baltic Sea samples and a culture from the Chesapeake Bay, USA. Cell shape varies from triangular to oval­round including intermediate forms in valve view. The thecal surface is covered by evenly distributed short spines, while the circular thecal pores are mainly situated near the valve margin. The intercalary band is rim-like, striated and covered with short evenly distributed spines. The architecture of the apical pore area is ornate and more complex than previously pointed out. It is V­shaped, located on the right valve in a shallow depression and accommodates a large elongated flagellar pore, and a small round auxiliary pore. Four distinct apical features are present: next to the auxiliary pore there is a curved collar, and adjacent to the flagellar pore arise a forked double tooth, a short single tooth, and a ridged edge near the left valve margin. Our study suggests that the ornamentation of the apical pore area of P.minimum is independent of cell shape or growth place,and it is considered a stable morphological character of this cosmopolitan morphospecies. [ABSTRACT FROM AUTHOR]

Four species of the red algal genus Dasya (Dasyaceae, Ceramiales), including two new species, are reported from Malaysia. Dasya iyengarii Børgesen and D. pilosa (Weber-van Bosse) Millar are reported from Malaysia for the first time, and their morphological features are described along with taxonomic comments. Dasya longifila Masuda et Uwai, sp. nov. is chiefly distinguished by its long, monosiphonous, pseudolateral filaments (often longer than the axis) in which intercalary cell divisions take place, and a small number of tetrasporangial stichidia and spermatangial branches per fertile pseudolateral from several related species that possess small-statured, sparselycorticatedaxes. DasyamalaccensisMasudaetUwai, sp. nov. ischaracterisedbyitsdiminutivethallus(up to 10 mm high) with thickly corticated axes, relatively short pseudolaterals, and narrow tetrasporangial stichidia and spermatangial branches. This species has no close relatives among small-sized species of Dasya. [ABSTRACT FROM AUTHOR]

As part of a species richness survey and ecological investigation of intertidal epilithic cyanobacteria, samples were collected during winter (November 1998–March 1999) and summer (July–September 1999) from various rocky shores around Hong Kong. Morphological and ecological descriptions are provided for 15 species belonging to the genus Oscillatoria, namely Oscillatoria cf. annae, O. bonnemaisonii, O. cf. borneti, O. brevis, O. chalybea, O. cf. curviceps, O. cf. irrigua, O. cf. limosa, O. margaritifera, O. cf. obtusa, O. cf. ornata, O. cf. princeps, O. cf. proboscidea, O. cf. salina and O. sancta, all of which are new records for Hong Kong. Of these, eight species (O. cf. annae, O. cf. borneti, O. cf. curviceps, O. cf. irrigua, O. cf. obtusa, O. cf. ornata, O. cf. proboscidea and O. cf. salina) are reported for the first time as marine epiliths. Most of the species were restricted to the mid- and lower eulittoral shore and were found in the winter months. [ABSTRACT FROM AUTHOR]

A range extension of Cutleria hancockii Dawson to the southern portion of the Gulf of California is presented based on collections developed in several localities from Bahiá de Los Angeles, Bahiá Concepción, Bahiá de La Paz and Bahiá de Los Muertos between March of 1996 and May of 2000. Punta Perico in Bahiá de Los Muertos represents the southern limit of the species extending the known distribution by 400 km. Several modifications in habitat and morphology were observed within the new range. The present reports also extend the vertical distribution of the species from the intertidal zone to subtidal areas with rocky and rhodolith substrates. As part of the habitat modification a reduction in the number of fronds per turf was observed. Morphologically the plants reduce their size significantly along the geographical cline, this suggests that temperature and light intensity are playing a major role in the distribution. An updated description of the species is provided based on the observation of variations in the range of morphological and anatomical features observed in the new collections. [ABSTRACT FROM AUTHOR]

The polysaccharide from Cladhymenia oblongifolia and some of its derivatives have been examined by 13C nuclear magnetic resonance spectroscopy and the spectra analysed with the techniques of set theory. The polysaccharide is an agaroid with significant levels of sulfation at most positions other than the axial hydroxyl group. The 4-linked units consist of anhydrogalactosyl and galactosyl units in the approximate ratio of 3:2. The galactose, but not the anhydrogalactose, units in the natural polymer have high levels of 2-sulfate ester, while low levels of galactose-3-sulfate are also present in the galactosyl residues. The 4-linked galactosyl units also contain significant levels of 6-sulfate, which is converted to anhydrogalactose by alkali treatment, including significant levels of anhydrogalactose-2-sulfate. The 3-linked units consist of high levels of galactose 2-sulfate, moderate levels of galactose 6-sulfate, and very low levels of pyruvate acetal. Methylation is largely absent from this polysaccharide. The approximate structure can be summarized in set theory nomenclature as 3DG|2S0.4(4,6)P0.05 6S0.4| - 4L(AG0.6, G0.4|2S0.353S0.16S0.3|). The polysaccharide is similar to those extracted from other members of the Rhodomelaceae to the extent that it is a non-gelling agaroid, but the high levels of 2-sulfation are unusual as is the total variation in sulfation. [ABSTRACT FROM AUTHOR]

Examines allozyme variation on individuals representing species of Sargassum from the Great Barrier Chief, Australia. Measurement of the allozyme variability; Observation of differences between morphological species; Analysis of gene differences.

Examines the morphology of ther theca in the dinoflagellate Peridiniella catenata using light and scanning electron microscopy. Analysis of the ecology and geographical distribution of the species; Development of Peridiniella in abundance in the sea ice; Naturality of the systematic position of P. catenata.

Chaetoceros Ehrenberg, subgenus Hyalochaete Gran, section Compressa contains the species Ch. Compressus Lauder 1864 and Ch. contortus Schütt 1895. On the basis of apparent intermediate forms, they were synonymized by Gran and Yendo. Rines and Hargraves suggested that they might be distinct taxa. Light and electron microscopy studies of a wide range of material supports that opinion, although further study of Ch. compressus sensu Lauder from the Indo-West Pacific is needed. Differences of opinion as to whether these taxa should be combined or considered distinct can be attributed to increased knowledge of the biology of diatoms, and advances in systematic theory. [ABSTRACT FROM AUTHOR]