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Molecular studies have revealed cryptic diversity and polyphyly in the genus Lithothamnion. In this study we aimed to investigate the diversity and phylogeny of specimens that are morphologically d...

A unique algal bed formation, composed largely of free-living geniculate coralline algae (articuliths), was recorded within the subtidal zone of Arraial do Cabo Bay, Brazil. The importance of these...

The red seaweed Hypnea pseudomusciformis has economic potential for mariculture as a source of carrageenan and other products. This work investigates this species along the Brazilian coastline by evaluating the effects of irradiance (40, 70, and 100 μmol photons m−2 s−1) on the number of differentiated branches (Br), growth rates (GR), photosynthesis parameters, and pigment content of tetrasporophytes from five distinct geographical populations extending from 5° to 27° S of latitude. The specimens showed intraspecific divergence for COI-5P marker, divided into three haplotypes with distinct geographical distribution. Although irradiance effects were significant only for GR and Br, intraspecific diversity was significant in all variables analyzed, with the haplotype of the tropical zone (5° to 12° S) displaying higher GR, Br, and maximum quantum yield (Fv/Fm) than the haplotype of the subtropical zone (23° to 27° S), which displayed higher pigment concentration. The geographic intermediate haplotype (19° S) displayed similar GR, Br, and Fv/Fm to the tropical haplotype, but similar pigment content to the subtropical haplotype. Our results indicate the presence of ecotypes within H. pseudomusciformis throughout its geographic distribution. Considering the set of physiological attributes, specimens from the tropical zone have higher potential for mariculture.

The genus Hypnea (Rhodophyta, Gigartinales) has currently 61 accepted species distributed in tropical, subtropical, and temperate regions, growing in different habitats with a wide range of environmental factors and interactions with abiotic and biotic factors. Some Hypnea species are consumed by humans mostly in Asian and Indo-Pacific countries and are also exploited as raw material for kappa-carrageenan production, consequently, have been harvested and/or cultivated in several countries for decades. Hypnea musciformis has the widest geographical distribution around the world and it is the most studied species. However, more molecular studies on H. musciformis from different countries are necessary to understand the phenotypic plasticity and to reveal cryptic species. The present review is a compilation of information on taxonomy, morphology, anatomy, life history, distribution, ecology, physiology, cultivation and harvesting, chemical composition, and biotechnological applications. Although Hypnea species are well known as sources of carrageenans, reports on chemical diversity and biological activities highlight their remarkable potential for biotechnological applications.

Two new Melobesioideae, Tectolithon fluminense gen. et sp. nov. and Crustaphytum atlanticum sp. nov., were described based on specimens collected at depths from 2 to 30 m in a tropical to subtropic...

Hypnea is a monophyletic genus with a complex nomenclatural and taxonomic history, and is an important commercial source of carrageenan. Phylogenies of this genus have been accessed based primarily on Asian species; however, recent studies performed in South America revealed a great diversity of species, for which phylogenetic relationships need to be evaluated. Three infrageneric sections are recognized in the genus: Pulvinatae, Spinuligerae, and Virgatae; however, morphological and molecular circumscriptions within each section lack clarity. In this study, we analyzed three distinct markers to establish phylogenetic relationships among Hypnea species. To assign each species to the correct section, morphological data were obtained from original descriptions, reference literature, and comparisons with type/topotype and herbaria specimens. Our analyses recovered robust phylogenies for the genus and provided new insights on the taxonomic status and relationships among and within Hypnea species. The combination of three genetic markers increased the resolution and support, resulting in the largest and best-resolved phylogeny of the genus to date. Single and combined analyses revealed that the three sections of the genus Hypnea are taxonomically irrelevant, as currently recognized. Morphological differences are not associated with monophyletic groups and similarities among clades could be better explained by convergent evolution in thallus habit.

In 1998 Critchley and Ohno published the book Seaweed resources of the world presenting a synthesis of knowledge on the subject from different regions and countries globally. One chapter by E.C. Oliveira was focused on Brazil. In this article, we present an update of the economically relevant species of Brazilian seaweeds, and their distribution along the coastline, and what has changed over 20 years in the status of the exploited resources, the new species with commercial potential, and relevant legislation. The only introduced commercial species, Kappaphycus alvarezii, was economically exploited for a while in Rio de Janeiro State, but nowadays there are no commercial activities on a large scale. Gracilaria farms in the northeast are still on an artisanal scale, but the expansion of activity is compromised by legal and bureaucratic barriers. Regulations related to the exploitation of natural beds and to the introduction of new strains of K. alvarezii were created between 2006 and 2008. At the end of this article, we present a reflection of what lessons have been learned and what are the prospects for seaweed cultivation in Brazil.

Studies of the Laurencia complex based on phylogenetic and DNA barcoding analyses revealed a new species, Laurencia longiramea Cassano, G.N. Santos, J.M.C. Nunes, M.C. Oliveira & M.T. Fujii sp. nov...

Marine heatwaves (MHWs) frequency and intensity are increasing around the globe, affecting marine ecosystems' structure and functioning. Understanding how key marine species respond to these short-term extreme events is urgent for predicting damage to coastal ecosystems. Hypnea pseudomusciformis presents distribution in different floristic provinces on the Brazilian coast: tropical, transition and warm-temperate. Here, we evaluate the effects of simulated heatwaves on H. pseudomusciformis populations by measuring the changes in algal growth, pigment content, and photosynthesis. Based on data for the last four decades, we characterized the MHW patterns for each of the three collection sites. Perturbation levels were identified as average intensity heatwave (Δ +2 °C), maximum intensity heatwave (Δ +4 °C) and extreme intensity heatwave (Δ +6 °C), with an average duration of seven days. Based on growth rate data, corroborated with measurements of photosynthesis fluorescence and pigment contents. H. pseudomusciformis populations exhibit distinct tolerance and physiological responses to MHWs. The tropical and transition specimens were affected by Δ + 4 °C and Δ + 6 °C MHW scenarios, while the warm-temperate specimens was the only one to recover in all the MHW scenarios tested. These data are worrisome under a global warming scenario and an increase in MHWs, indicating that tropical and transition specimens of H. pseudomusciformis may be at risk of local extinction. This knowledge will be fundamental in driving any future management intervention or policy change for the conservation of marine ecosystems.

Coralline red algae (CRA) are key players in the construction and maintenance of biogenic reefs, and they have important functional roles in ecological systems in the Southwestern Atlantic (SWA). Like many other marine organisms, CRA are currently affected by global and local stressors, but little is known about their biodiversity and the environmental drivers that influence their distribution patterns in the SWA. In the present study, we quantified the species richness of CRA in six ecoregions within the SWA using DNA-based species delimitation methods. We then verified their distribution and identified the main drivers shaping the macroecological patterns of richness and β-diversity. We found 79 phylogenetic species that belong to the three main CRA orders (Sporolithales, Corallinales, and Hapalidiales), in the tropical and warm temperate SWA. Temperature, nutrients, and water current velocity were the main environmental drivers of CRAs in the evaluated ecoregions. The Eastern Brazil ecoregion stands out due to its high richness, exclusive species, β-diversity between ecoregions, and as a transitional zone of the SWA. The results of our study have several important practical implications with repercussions for monitoring actions and conservation planning for the coastal region. These results show that each ecoregion has unique characteristics, and the mesophotic habitat is of primary importance because it harbors species that are not found in other habitats, and because it provides structural connectivity with shallower habitats.

Multiple-marker (COI-5P, UPA,psbA andrbcL-3P) and two algorithmic approaches [automatic barcode gap discovery (ABGD) and Poisson tree process (PTP)] were used for species delimitation of Lithophylloideae in Brazil. The integrative approach was mostly congruent between markers and algorithmic methods of species delimitation, suggesting the occurrence of 24 species. Based on morphology and molecular data,Amphiroa rigida,Amphiroa vanbosseae,Lithophyllum atlanticum,Lithophyllum kaiseri,Lithophyllum margaritae,Titanoderma pustulatum,Titanoderma prototypumandPaulsilvella huveorum, which were previously reported for Brazil, are confirmed in this work. Six new species are distinguished by both molecular and morphological traits, and they are provisionally named asAmphiroasp. 1,Amphiroasp. 2,Amphiroasp. 3,Lithophyllumsp. 1,Lithophyllumsp. 2 andLithophyllumsp. 3. Another 10 species are cryptic and cannot be distinguished based on traditionally used morphological traits. These includeAmphiroasp. 4,Lithophyllumsp. 4, three species that are morphologically named underAmphiroa beauvoisii, and six that share the morphology described forAmphiroa fragilissima. All four markers used were useful for species delimitation. However, a combination of practical aspects and levels of intra- and interspecific divergence values led us to propose the use ofrbcL-3P as a standard DNA barcode marker for the Corallinales.

Heavy metals are toxic to all organisms and their presence can have great impact on ecosystems. The study of strategies to remove contaminants is thus important, as is increased understanding of the resistance mechanisms of candidate organisms to be used as phytoremediators. The present study evaluate the genes involved in chronic stress using two different expression techniques to profile the transcriptome of the marine macroalga Gracilaria tenuistipitata after exposure to the EC50 of cadmium (Cd) and copper (Cu). Some known molecular markers for chronic pollution were observed, indicating that resistance mechanisms are induced within the first hour of treatment. Differences in gene expression response patterns between the two metals were found, where Cd up-regulated the expressions of superoxide dismutase and the nitrate transporter NRT even after 6 days of exposure. Expressions of both nuclear and chloroplast-encoded proteins were affected, and a stronger tolerance mechanism involving proteins of unknown function is certainly connected to the tolerance of the alga, warranting further studies. After 6 days of exposure to Cd or Cu, a slower acclimation was detected for the latter. Analysis of the photosynthetic rate revealed acclimation over time, corroborating a previous study where G. tenuistipitata was able to accumulate these metals and tolerate their negative effects, reinforcing the potential use of this macroalga in integrated bioremediation processes.

Seven species of the economically important agarophyte genus Pterocladiella were previously reported from Brazil: P. australafricanensis, P. bartlettii, P. beachiae, P. caerulescens, P. capillacea, P. sanctarum and P. taylorii. Only P. australafricanensis, P. bartlettii, P. beachiae and P. capillacea were previously confirmed by molecular data. This study surveyed Pterocladiella species from Brazil using both morphological and molecular analyses. DNA bar coding and phylogenetic analyses were carried out with mitochondrial COI-5P and plastid rbcL markers. Both molecular and morphological data confirmed the presence of five species in Brazil: P. australafricanensis, P. bartlettii, P. beachiae, P. capillacea and a new record of P. media. Pterocladiella beachiae and P. bartlettii are common intertidal species along Brazilian coasts, and they were the only species found along the northeast coast. The diversity of Pterocladiella species on southeast coasts is higher, and all species were found there. ...

This study represents the efforts of a network of researchers to characterise the large, floating Sargassum (Fucales, Phaeophyceae) biomass that had reached the Brazilian coast in 2014 and 2015. Material collected during these events was identified as Sargassum natans and S. fluitans using morphological characteristics; ITS2 sequences showed low divergence (0%–3%) with sequences of nine other Sargassum species. Several epiphytic macroalgae, invertebrates and fishes were associated with the floating Sargassum. Satellite images did not support the hypothesis of slicks moving south from the Sargasso Sea in the northern Atlantic Ocean. This strengthens the hypothesis that there is a matrix of pelagic Sargassum in the central Atlantic Ocean and that biomass accumulation should be considered a result of the combination of physicochemical seawater conditions and biological interactions. The biomass accumulation of the stranded Sargassum was estimated during four events, peaking in 98 kg m−2 wet weight ...

International audience; In this study, we explored how past terrestrial and marine climate changes have interacted to shape the phylogeographic patterns of the intertidal red seaweed Gracilaria caudata, an economically important species exploited for agar production in the Brazilian north‐east. Seven sites were sampled along the north‐east tropical and south‐east sub‐tropical Brazilian coast. The genetic diversity and structure of G. caudata was inferred using a combination of mitochondrial (COI and cox2‐3), chloroplast (rbcL) and 15 nuclear microsatellite markers. A remarkable congruence between nuclear, mitochondrial and chloroplast data revealed clear separation between the north‐east (from 03° S to 08° S) and the south‐east (from 20° S to 23° S) coast of Brazil. These two clades differ in their demographic histories, with signatures of recent demographic expansions in the north‐east and divergent populations in the south‐east, suggesting the maintenance of several refugia during the last glacial maximum due to sea‐level rise and fall. The Bahia region (around 12o S) occupies an intermediate position between both clades. Microsatellites and mtDNA markers showed additional levels of genetic structure within each sampled site located south of Bahia. The separation between the two main groups in G. caudata is likely recent, probably occurring during the Quaternary glacial cycles. The genetic breaks are concordant with (1) those separating terrestrial refugia, (2) major river outflows and (3) frontiers between tropical and subtropical regions. Taken together with previously published eco‐physiological studies that showed differences in the physiological performance of the strains from distinct locations, these results suggest that the divergent clades in G. caudata correspond to distinct ecotypes in the process of incipient speciation and thus should be considered for the management policy of this commercially important species.

Populations of the marine benthic red macroalgae Hypnea musciformis and Hypnea pseudomusciformis along the Atlantic and Pacific Oceans were tested for phylogeographic structure using the DNA barcode COI-5P combined with rbcL for the construction of the phylogenetic tree. Strong patterns of genetic structure were detected across 210 COI-5P DNA sequences, and 37 COI-5P haplotypes were found, using multiple statistical approaches. Hypnea musciformis was found in the Northeast and Northwest Atlantic, the Mediterrean Sea, Namibia, and along the Pacific coast of Mexico. Two new putative species were detected, Hypnea sp. 1 in the Caribbean Sea and Hypnea sp. 2 in the Dominican Republic. Three distinct marine phylogeographic provinces were recognized in the Southern Hemisphere for H. pseudomusciformis: Uruguay, South-Southeast Brazil, and Northeast Brazil. The degree of genetic isolation and distinctness among these provinces varied considerably. The Uruguay province was the most genetically distinct, as characterized by four unique haplotypes not shared with any of the Brazilian populations. Statistically significant results support both, isolation by distance and isolation by environment hypotheses, explaining the formation and mantainance of phylogeographic structuring along the Uruguay-Brazil coast. Geographic, taxonomic and molecular marker concordances were found between our H. pseudomusciformis results and published studies. Furthermore, our data indicate that the Hawaiian introduced populations of H. musciformis contain Hypnea sp. 1 haplotypes, the current known distribution of which is restricted to the Caribbean.

Gelidium coarctatum Kutzing was a poorly known species described from the coast of Brazil. The name was picked up by Ugadim and applied to a common species on the tropical Brazil coast. Analyses of partial rbcL sequences and morphological characters of the G. coarctatum holotype have shown that it is a synonym of Gelidium capense (Gmelin) P.C.Silva and that the name G. coarctatum had been misapplied to the common tropical species of Gelidium in Brazil. The latter was described as Gelidium lineare sp. nov., a species characterized externally by determinate lateral branches giving axes a generally linear outline and internally by copious rhizines being concentrated in the outer medulla and inner cortex. This species was also found to be common along the Caribbean coast of Panama and may be widespread in the tropical western Atlantic and Caribbean Sea.

Specimens previously described as Hypnea musciformis and Hypnea nigrescens in Brazil were shown to be morphological variants of a new species named Hypnea pseudomusciformis, which has been used for the production of carrageenan on the coast of Brazil. In this study, individuals of both morphological variants were collected in the field and cultivated in unialgal culture conditions. The life history of both variants was completed in 118 days. Tetrasporophytes produced tetrasporangia in 40 days. Released tetraspores germinated and 15 days later, an erect cylindrical axis developed from basal disk. At the age of 35 days, spermatangial conceptacles could be observed, and after 3 days of co-culture of male and female gametophytes, cystocarps could be observed, indicating the occurrence of fertilization. Finally, carpospores were released from cystocarps after 10 days, germinated and originated new tetrasporophytes in 15 days. When cultured, the morphological differences between the “musciformis” and “nigrescens” variants were attenuated and the life histories were the same. Furthermore, both morphological variants had different growth rates, but similar pigment content. These results corroborate that, for Brazil, specimens previously identified as H. musciformis and H. nigrescens are variants of H. pseudomusciformis, a highly plastic species.

In recent years, the use of molecular data in algal systematics has increased as high-throughput sequencing (HTS) has become more accessible, generating very large datasets at a reasonable cost. In...

Grateloupia turuturu is a Pacific native species with invasive behaviour that leads to a wide distribution around the world. This study reports collections of fertile tetrasporophytes and female gametophytes of G. turuturu on southern Brazilian coasts and constitutes its first record for the south-western Atlantic. The identity of G. turuturu was confirmed through molecular (COI-5P and rbcL markers) and morphological assessments. Putative paths of introduction are discussed.

Hypnea musciformis, a red macroalga widely distributed in tropical and subtropical coasts around the world, has great economic importance as a source of carrageenan for industrial production. In this work, the DNA barcode marker COI-5P and the plastid rbcL gene, in addition to morphological studies, were used to investigate this species on the coast of Brazil and compare it with specimens from other countries. A total of 128 sequences were obtained in this study for 100 specimens from Brazil and 15 specimens from other countries, including the type locality in Italy. The divergence between South American sequences and sequences from Italy for H. musciformis was significantly high for both markers, indicating that the specimens found on the Brazilian coast belong to a different species. Considering the data gathered from molecular markers and morphological analysis, the specimens previously identified morphologically as “H. musciformis”, “Hypnea nigrescens”, and “Hypnea valentiae” collected in Brazil were considered morphological variations of the new species described in this paper, named Hypnea pseudomusciformis Nauer, Cassano & M.C. Oliveira, sp. nov. The identification of specimens based only on morphological characteristics proved to be unsatisfactory for reasons that could be attributed to phenotypic plasticity in this species. Thus, the technique of DNA barcoding, especially with respect to the COI-5P marker, was essential for the identification and definition of species, revealing scenarios that would otherwise be ignored by using only morphological analysis.

The genus Porphyra sensu lato of the Bangiales has been reported from the Brazilian coast since the 19th century. However, a major worldwide taxonomic revision of the Bangiales indicated that the foliose genus present in Brazil was Pyropia and that Porphyra sensu stricto has not been recorded from this region. A revision of the species of Pyropia in Brazil, based on sequence analysis of molecular markers (rbcL and SSU rDNA) and complemented with morphology, revealed the occurrence of five distinct species in Brazil: P. acanthophora, P. spiralis, P. suborbiculata, P. tanegashimensis and P. vietnamensis. Possible events of Pyropia species introduction in Brazil are discussed in the context of phylogenetic analyses. Pyropia acanthophora and P. spiralis, regarded as southwestern Atlantic species, were not closely related in phylogenetic analyses. Pyropia acanthophora grouped with the possibly introduced Indo-Pacific species P. suborbiculata, P. tanegashimensis and P. vietnamensis. Analysis of available COI-5P...

Gracilariaceae has a worldwide distribution including numerous economically important species. We applied high-throughput sequencing to obtain organellar genomes (mitochondria and chloroplast) from 10 species of Gracilariaceae and, combined with published genomes, to infer phylogenies and compare genome architecture among species representing main lineages. We obtained similar topologies between chloroplast and mitochondrial genomes phylogenies. However, the chloroplast phylogeny was better resolved with full support. In this phylogeny, Melanthalia intermedia is sister to a monophyletic clade including Gracilaria and Gracilariopsis, which were both resolved as monophyletic genera. Mitochondrial and chloroplast genomes were highly conserved in gene synteny, and variation mainly occurred in regions where insertions of plasmid-derived sequences (PDS) were found. In mitochondrial genomes, PDS insertions were observed in two regions where the transcription direction changes: between the genes cob and trnL, and trnA and trnN. In chloroplast genomes, PDS insertions were in different positions, but generally found between psdD and rrs genes. Gracilariaceae is a good model system to study the impact of PDS in genome evolution due to the frequent presence of these insertions in organellar genomes. Furthermore, the bacterial leuC/leuD operon was found in chloroplast genomes of Gracilaria tenuistipitata, G. chilensis, and M. intermedia, and in extrachromosomal plasmid of G. vermiculophylla. Phylogenetic trees show two different origins of leuC/leuD: genes found in chloroplast and plasmid were placed with proteobacteria, and genes encoded in the nucleus were close to Viridiplantae and cyanobacteria.

Nephroselmis is composed by unicellular nanoplanktonic organisms, occurring predominantly in marine environments. Currently, 14 species are taxonomically accepted. Nephroselmis viridis was described in 2011 and strains were isolated from Indic and Pacific Oceans. Since then, it was not recorded in other places. A strain was isolated from coastal waters of Brazil by micropipetting and washing, and cultivated in f/2 medium for morphological observations (light, confocal, SEM and TEM) and molecular phylogeny inferences (maximum likelihood and Bayesian). The cells are asymmetrical, have two unequal flagella, one cup-shaped chloroplast with an eyespot, and a large starch covered pyrenoid. Chloroplast thylakoids intrude into the pyrenoid and organic scales cover all cell body and flagella. Molecular phylogeny (18S rRNA) clustered the isolated strain with other Nephroselmis viridis sequences, and the species is the sister of the N. olivacea, the type species of the genus. Morphology and molecular phylogeny corroborate the strain identification, and it is the first time this species is recorded in Brazil and in the Atlantic Ocean.

A new species, Gayralia brasiliensis (Ulotrichales, Chlorophyta), is described from Brazil on the basis of ontogenetic, morphological, and molecular phylogenetic data. Liberation of zooids from the monostromatically bladed thalli occurred by disintegration of the zooidangium wall, releasing four biflagellate cells with prominent eyespots. Fusion of zooids was not observed. After zooid attachment, cell divisions gave rise to uniseriate filaments that developed into fan-shaped blades. Only asexual reproduction was observed; this took place through recycling of blades by germination of zooids. Phylogenetic analysis based on rDNA internal transcribed spacer (ITS) sequences showed that G. brasiliensis specimens formed a monophyletic group closely related to Monostroma nitidum and two unidentified monostromatic species from Japan and Tanzania. The genus Monostroma was polyphyletic in our analysis. ITS sequences also confirmed the presence of a second monostromatic species of Ulotrichales in the Brazilian coast, Gayralia oxysperma. There were overlapping morphological and life history traits between G. brasiliensis and G. oxysperma. However, these two species were clearly divergent based on ITS sequences and ontogeny.

Barufi J.B., Mata M.T., Oliveira M.C. and Figueroa F.L. 2012. Nitrate reduces the negative effect of UV radiation on photosynthesis and pigmentation in Gracilaria tenuistipitata (Rhodophyta): the photoprotection role of mycosporine-like amino acids. Phycologia 51: 636–648. DOI: 10.2216/10.77.1 Photoprotection of the agarophyte red alga Gracilaria tenuistipitata against ultraviolet radiation (UVR) was investigated in algae submitted for 1 week to photosynthetically active radiation (PAR, 260 μmol photons m−2 s−1) or PAR + UVR (UV-A, 8.13 W m−2 and UV-B, 0.42 W m−2) under different nitrogen concentrations: 0, 0.1, and 0.5 mM of NO3−. Photosynthetic pigments decreased during the time of the experiment mainly under low nitrogen supply and UVR. Incubation under high nitrogen supply (0.5 mM) sustained the photosynthetic levels over time. In contrast, mycosporine-like amino acids (MAAs) increased up to eightfold in the presence of UVR and 0.5 mM NO3−. Under PAR + UVR, maximal quantum yield was positively correla...

Species in the genus Gracilaria that display conspicuously flattened vegetative morphologies are a taxonomically challenging group of marine benthic red algae. This is a result of their species richness, morphological similarity, and broad phenotypic plasticity. Within this group, the Gracilaria domingensis complex is one of the most common, conspicuous, and morphologically variable species along the tropical western Atlantic Ocean. Previous research has identified that members of this complex belong to two distantly related clades. However, despite this increased phylogentic resolution, species delimitations within each of these clades remain unclear. Our study assessed the species diversity within this difficult complex using morphological and molecular data from three genetic markers (cox1, UPA, and rbcL). We additionally applied six single-marker species delimitation methods (SDM: ABGD, GMYCs, GMYCm, SPN, bPTP, and PTP) to rbcL, which were largely in agreement regarding species delimitation. These results, combined with our analysis of morphology, indicate that the G. domingensis complex includes seven distinct species, each of which are not all most closely related: G. cervicornis; a ressurected G. ferox; G. apiculata subsp. apiculata; a new species, Gracilaria baiana sp. nov.; G. intermedia subsp. intermedia; G. venezuelensis; and G. domingensis sensu stricto, which includes the later heterotypic synonym, G. yoneshigueana. Our study demonstrates the value of multipronged strategies, including the use of both molecular and morphological approaches, to decipher cryptic species of red algae.

Hypnea has an intricate nomenclatural history due to a wide pantropical distribution and considerable morphological variation. Recent molecular studies have provided further clarification on the systematics of the genus; however, species of uncertain affinities remain due to flawed taxonomic identification. Detailed analyses coupled with literature review indicated a strong relationship among H. aspera, H. cervicornis, H. flexicaulis, and H. tenuis, suggesting a need for further taxonomic studies. Here, we analyzed sequences from two molecular markers (COI-5P and rbcL) and performed several DNA-based delimitation methods (mBGD, ABGD, SPN, PTP and GMYC). These molecular approaches were contrasted with morphological and phylogenetic evidence from type specimens and/or topotype collections of related species under a conservative approach. Our results demonstrate that H. aspera and H. flexicaulis represent heterotypic synonyms of H. cervicornis and indicate the existence of a misidentified Hypnea species, widely distributed on the Brazilian coast, described here as a new species: H. brasiliensis. Finally, inconsistencies observed among our results based on six different species delimitation methods evidence the need for adequate sampling and marker choice for different methods.

The diversity of branched Halymenia species in Brazil was assessed by molecular analyses and morphological examination to clarify the status of taxa previously identified as Halymenia floresii and H. pseudofloresii. Molecular tools included sequencing the COI-5P molecular marker for DNA barcoding and rbcL for phylogenetic inferences. Both molecular and morphological results demonstrated that Brazilian specimens previously attributed to H. floresii and H. pseudofloresii do not correspond to these species but constitute three distinct lineages that we propose as the new species: Halymenia ignifera sp. nov., Halymenia pinnatifida sp. nov. and Halymenia silviae sp. nov. We propose that H. floresii and H. pseudofloresii be removed from the Brazilian marine flora. We highlight that without the use of molecular tools, the morphological divergences observed in Brazilian specimens could be misinterpreted as morphological plasticity and lead to incorrect species determinations.

Currently, five genera are assigned to red seaweeds of the Laurencia complex worldwide: Chondrophycus, Laurencia s.s., Osmundea, Palisada and Yuzurua. The genera are segregated on the basis of morphological characters, especially the reproductive traits, and molecular sequences of the plastid-encoded gene rbcL. Four of the genera have been resolved as monophyletic, but not Laurencia s.s. In this study based on an rbcL gene phylogeny we show the presence of a sixth lineage within the Laurencia complex, viz., Laurencia marilzae plus two unidentified species of Laurencia from Brazil. The phylogenetic position of this group, combined with the high genetic divergence from Laurencia s.s. (8.2–11%), strongly support the establishment of a sixth genus for the complex, proposed here as Laurenciella gen. nov. This new taxon differs from Laurencia s.s. and from the other genera of the complex by molecular sequence data, but is indistinguishable from Laurencia s.s. by the usual morphological features.

The University of Sao Paulo Gracilariaceae Germplasm Bank has 50 strains collected mostly in Brazil, but also elsewhere in the world. This bank has been used as a source of material for research developed locally and abroad. With over 200 species, some of which have high economic value, the family Gracilariaceae has been extensively studied. Nonetheless, taxonomic problems still persist by the existence of cryptic species, phenotypic plasticity, and broad geographic distribution. In the case of algae kept in culture for long periods of time, the identification is even more problematic as a consequence of considerable morphological modification. Thus, the use of molecular markers has been shown to be an efficient tool to elucidate taxonomic issues in the group. In this work, we sequenced the 5′-end of the cox1 gene for 41 strains and the universal plastid amplicon (UPA) plastid region for 45 strains, covering all 50 strains in the bank. In addition, the rbcL for representatives of the cox1/UPA clusters was sequenced for 14 strains. The original species identification based on morphology was compared with the molecular data obtained in this work, resulting in the identification of 13 different species. Our analyses indicate that cox1 and UPA are suitable markers for the delineation of species of Gracilariales in the germplasm bank. The addition of DNA barcode tags to the samples in the Gracilariaceae germplasm bank and the molecular identification of the species will make this bank even more useful for future research as the species can be easily traced and confirmed.

Morphological and molecular studies have been performed on Laurencia dendroidea derived from Brazil and the Canary Islands. This species possesses all of the characters that are typical of the genus Laurencia, including the production of the first pericentral cell underneath the basal cell of the trichoblast; the production of tetrasporangia from particular pericentral cells without the formation of additional fertile pericentral cells; spermatangial branches that are produced from one of two laterals on the suprabasal cell of the trichoblasts; and a procarp-bearing segment that possesses five pericentral cells. The phylogenetic position of L. dendroidea was inferred by analysing the chloroplast-encoded rbcL gene sequences of 51 taxa. Phylogenetic analyses revealed that the taxa previously identified and cited in Brazil as Laurencia filiformis, L. majuscula and L. obtusa and in the Canary Islands as L. majuscula all represent the same taxonomic entity and examination of type material allowed us to identif...

This paper is part of an extensive study on the biodiversity of the macroalgal flora of Sao Paulo state, SE Brazil. Previous assessments were based only on morphological descriptions. Here, we tested the effectiveness of DNA barcoding, in comparison with morphological observations for the recognition and cataloging of species. The focus of this study is the genus Porphyra, which is a conspicuous component of the upper intertidal on rocky shores of this region. With five currently accepted species, we have sequenced three short markers: cox1, cox2–3 spacer and UPA to establish the first DNA barcode database for the Porphyra species from the Brazilian coast. The three markers, although with different evolution rates, recovered a cryptic species (Porphyra sp. 77), grouped two different species (Porphyra drewiana and Porphyra spiralis) that are being synonymized, and finally indicated that varieties within P. acanthophora and P. spiralis are merely morphological, with no sequence divergence in the studied molecular markers.

This study evaluated the phylogenetic relationship among samples of "Chantransia" stage of the Batrachospermales and Thoreales from several regions of the world based on sequences of two genes-the plastid-encoded RUBISCO LSU gene (rbcL) and the nuclear SSU ribosomal DNA gene (SSU rDNA). All sequences of "Chantransia macrospora" were shown to belong to Batrachospermum macrosporum based on both molecular markers, confirming evidence from previous studies. In contrast, nine species are now associated with "Chantransia pygmaea," including seven species of the Batrachospermales and two of the Thoreales. Therefore, the presence of "C. macrospora" in a stream can be considered reliable evidence that it belongs to B. macrosporum, whereas the occurrence of "C. pygmaea" does not allow the recognition of any particular species, since it is associated with at least nine species. Affinities of "Chantransia" stages to particular taxa were congruent for 70.5% of the samples comparing the rbcL and SSU analyses, which were associated with the same or closely related species for both markers. Sequence divergences have been reported in the "Chantransia" stage in comparison to the respective gametophyte, and this matter deserves further attention.

We have studied the effects of nitrate supply under photosynthetic active radiation (PAR) plus ultraviolet radiation (UVR) exposure on photosynthetic pigments (chlorophyll a and carotenoids), photoprotective UV screen mycosporine-like amino acids (MAAs), and photosynthetic parameters, including the maximum quantum yield (F v/F m) and electron transport rate (ETR) on the red agarophyte Gracilaria tenuistipitata. Apical tips of G. tenuistipitata were cultivated under ten different concentrations of NO 3 − for 7 days. It has been shown that G. tenuistipitata cultured under laboratory conditions has the ability to accumulate high amounts of MAAs following a nitrate concentration-dependent manner under PAR + UVR. Two MAAs were identified, shinorine and porphyra-334. The relative concentration of the first increased under high concentrations of nitrate, while the second one decreased. The presence of antheraxanthin is reported for the first time in this macroalgae, which also contains zeaxanthin, lutein, and β-carotene. The accumulation of pigments, photoprotective compounds, and photosynthetic parameters of G. tenuistipitata is directly related to N availability. All variables decreased under low N supplies and reached constant maximum values with supplements higher than 0.5 mM NO 3 − . Our results suggest a high potential to acclimation and photoprotection against stress factors (including high PAR and UVR) directly related to N availability for G. tenuistipitata.

Gracilaria tenuistipitata , a species of commercial interest, is becoming a model organism for studies on red algal physiology and molecular biology as it can be grown easily in vitro under a broad range of conditions. Most of the experiments carried out around the world have been based on a tetrasporophytic clone isolated in our laboratory from a specimen collected in China. Here we describe the life history of this species, give anatomic details of the reproductive structures, illustrate the morphological variability of tetraspore progeny and compare the growth rate of gametophytic and sporophytic thalli. Tetrasporophytic branches showed higher growth rates than gametophytic branches.

Palisada flagellifera (Ceramiales, Rhodophyta) is recorded for the first time in the eastern Atlantic Ocean off Tenerife, La Gomera, La Palma and Fuerteventura, Canary Islands, Spain. The specimens were collected in 2006–2009 growing from the lower intertidal to subtidal zones to 2 m depth at sites exposed to wave action. The species possesses a palisade-like arrangement of cortical cells in cross section, lacks secondary pit connections between them, and has tetrasporangia produced by three fertile pericentral cells (the third and the fourth additional and the second that becomes fertile), and a right-angled arrangement of tetrasporangia. Gametangia were not observed. The phylogenetic relationships were inferred by analyses of the chloroplast-encoded rbcL gene sequences from 46 taxa. The Canarian and Brazilian P. flagellifera specimens formed a highly supported clade with a low level of genetic variation in the rbcL sequences (0.02–0.04%), confirming that they are the same taxonomic entity. This study expands the geographical distribution of P. flagellifera to the eastern Atlantic Ocean.

The enzyme nitrate reductase (NR) responsible for the conversion of nitrate to nitrite is considered to be the rate-limiting step in nitrogen assimilation. The economically important marine macroalga Gracilaria tenuistipitata presents a circadian oscillation in NR protein content and activity. In order to identify if the regulation of NR in G. tenuistipitata happens at transcriptional levels, the NR cDNA and gene were sequenced and the NR mRNA expression was studied. Analysis of the sequenced gene revealed absence of introns which is unusual for NR genes. The transcriptional profiling revealed a circadian rhythm for NR; furthermore, a rhythm was observed in constant light condition, suggesting a possible regulation by the biological clock at the mRNA levels for NR in G. tenuistipitata.

Necchi O. Jr., Vis M.L. and Oliveira M.C. 2010. Phylogenetic relationships in Kumanoa (Batrachospermales, Rhodophyta) species in Brazil with the proposal of Kumanoa amazonensis sp. nov. Phycologia 49: 97–103. DOI: 10.2216/09-24.1 This study evaluated the species-level taxonomy and phylogenetic relationship among Kumanoa species from Brazil with other regions of the world based on the plastid-encoded RUBISCO large subunit gene (rbcL). Partial rbcL sequences were obtained for 11 Kumanoa specimens. Eight species are recognised from Brazil on the basis of molecular and morphological data: seven previously described (K. abilii, K. ambigua, K. breviarticulata, K. cipoensis, K. equisetoidea, K. globospora and K. procarpa) and a new species here proposed (K. amazonensis sp. nov. Necchi & Vis). The new species has reduced and dense whorls but differs from the two closest related species in lacking secondary fascicles. Previously proposed infrageneric categories were not supported by the molecular data. Sp...

Geitlerinema amphibium (C. Agardh ex Gomont) Anagn. and G. unigranulatum (Rama N. Singh) Komarek et M. T. P. Azevedo are morphologically close species with characteristics frequently overlapping. Ten strains of Geitlerinema (six of G. amphibium and four of G. unigranulatum) were analyzed by DNA sequencing and transmission electronic and optical microscopy. Among the investigated strains, the two species were not separated with respect to cellular dimensions, and cellular width was the most varying characteristic. The number and localization of granules, as well as other ultrastructural characteristics, did not provide a means to discriminate between the two species. The two species were not separated either by geography or environment. These results were further corroborated by the analysis of the cpcB-cpcA intergenic spacer (PC-IGS) sequences. Given the fact that morphology is very uniform, plus the coexistence of these populations in the same habitat, it would be nearly impossible to distinguish between them in nature. On the other hand, two of the analyzed strains were distinct from all others based on the PC-IGS sequences, in spite of their morphological similarity. PC-IGS sequences indicate that these two strains could be a different species of Geitlerinema. Using morphology, cell ultrastructure, and PC-IGS sequences, it is not possible to distinguish G. amphibium and G. unigranulatum. Therefore, they should be treated as one species, G. unigranulatum as a synonym of G. amphibium.

V. CASSANO ,J. D IAZ-LARREA ,A. S ENTIES, M.C. OLIVEIRA ,M. C ANDELARIA GIL-RODRIGUEZ AND M.T. FUJII. 2009. Evidence for the conspecificity of Palisada papillosa with P. perforata (Ceramiales, Rhodophyta) from the western and eastern Atlantic Ocean on the basis of morphological and molecular analyses. Phycologia 48: 86-100. DOI: 10.2216/08- 22.1. Morphological and molecular studies were carried out on Palisada papillosa and P. perforata from the Canary Islands (type locality of P. perforata), Mexico and Brazil. The two species have been distinguished by features of their external morphology such as size and degree of compactness of the thalli, presence or absence of arcuate branches, branching pattern and basal system. A detailed morphological comparison between these taxa showed that none of the vegetative anatomical or reproductive characters was sufficient to separate these species. The presence or absence of cortical cells in a palisade-like arrangement, also previously used to distinguish these species, is not applicable. The species present all characters typical of the genus, and both share production of the first pericentral cell underneath the basal cell of the trichoblast, production of two fertile pericentral cells (the second and the third additional, the first remaining sterile), spermatangial branches produced from one of two laterals on the suprabasal cell of trichoblasts, and the procarp- bearing segment with four pericentral cells. Details of the procarp are described for the species for the first time. The phylogenetic position of these species was inferred by analysis of the chloroplast-encoded rbcL gene sequences from 39 taxa, using one other Rhodomelacean taxon and two Ceramiaceae as outgroups. Relationships within the clade formed by P. papillosa and P. perforata have not been resolved due to the low level of genetic variation in their rbcL sequences (0-0.4%). Considering this and the morphological similarities, we conclude that P. papillosa is a taxonomic synonym of P. perforata. The phylogenetic analyses also supported the nomenclatural transfer of two species of Chondrophycus to Palisada, namely, P. patentiramea (Montagne) Cassano, Sento ´es, Gil-Rodro ´guez & M.T. Fujii comb. nov. and P. thuyoides (Kutzing) Cassano, Sento ´es, Gil-Rodro ´guez & M.T. Fujii comb. nov.

Nitrate is one of the most important stimuli in nitrate reductase (NR) induction, while ammonium is usually an inhibitor. We evaluated the influence of nitrate, ammonium or urea as nitrogen sources on NR activity of the agarophyte Gracilaria chilensis. The addition of nitrate rapidly (2 min) induced NR activity, suggesting a fast post-translational regulation. In contrast, nitrate addition to starved algae stimulated rapid nitrate uptake without a concomitant induction of NR activity. These results show that in the absence of nitrate, NR activity is negatively affected, while the nitrate uptake system is active and ready to operate as soon as nitrate is available in the external medium, indicating that nitrate uptake and assimilation are differentially regulated. The addition of ammonium or urea as nitrogen sources stimulated NR activity after 24 h, different from that observed for other algae. However, a decrease in NR activity was observed after the third day under ammonium or urea. During the dark phase, G. chilensis NR activity was low when compared to the light phase. A light pulse of 15 min during the dark phase induced NR activity 1.5-fold suggesting also fast post-translational regulation. Nitrate reductase regulation by phosphorylation and dephosphorylation, and by protein synthesis and degradation, were evaluated using inhibitors. The results obtained for G. chilensis show a post-translational regulation as a rapid response mechanism by phosphorylation and dephosphorylation, and a slower mechanism by regulation of RNA synthesis coupled to de novo NR protein synthesis.

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.

RNA isolation is essential to study gene expression at the molecular level. However, RNA isolation is difficult in organisms (plants and algae) that contain large amounts of polysaccharides, which co-precipitate with RNA. Currently, there is no commercial kit available, specifically for the isolation of high-quality RNA from these organisms. Furthermore, because of the large amounts of polysaccharides, the common protocols for RNA isolation usually result in poor yields when applied to algae. Here we describe a simple method for RNA isolation from the marine red macroalga Gracilaria tenuistipitata var. liui Zhang et Xia (Rhodophyta), which can be applied to other plants and algae.

International audience; The two red algal species, Gracilaria birdiae Plastino and E.C. Oliveira and Gracilaria caudata J. Agardh, are the most important natural sources of agar in Brazil. Using the 454 sequencing system, we identified 464 and 487 perfect microsatellite loci in 6908 and 9602 sequences/contigs from G. birdiae and G. caudata, respectively. After a conservative removal of potentially problematic loci, 144 loci were tested (72 from each species). A total of 25 polymorphic microsatellite loci were defined (13 loci for G. birdiae and 17 loci for G. caudata, including 5 loci common to both species). The five microsatellite loci that cross-amplified in both species showed species-specific differences in allele size. Polymorphic microsatellite loci were used to assess the genetic diversity of both species in their main harvest and cultivation areas on the Brazilian coast. Gene diversity was similar in G. birdiae and G. caudata. However, significant heterozygote deficiency was observed in G. birdiae, whereas heterozygote excess occurred in G. caudata, suggesting that these two related species differ in their mating system. These results also raised new questions on their biology in the field and on their patterns of genetic structure across their geographical ranges. In addition, the 20 loci developed in this study proved successful in identifying each individual in the field as a unique multilocus genotype, and will be useful for studying lineage sorting, breeding programs, or conservation issues.

Morphological identification of species in the order Gelidiales can be difficult and controversial because of phenotypic plasticity, the low numbers of reproductive specimens and poorly defined taxonomic boundaries. A DNA barcoding survey of Brazilian specimens of Gelidiales, employing neighbor-joining and Automatic Barcode Gap Discovery analyses, indicated the presence of 23 statistically robust primary species hypotheses (PSH). In addition to the cytochrome oxidase I gene (COI-5P), the chloroplast universal plastid amplicon (UPA) marker was also sequenced and submitted to the same analyses. Representatives of each COI-5P/UPA PSH were selected for rbcL sequence analysis to further corroborate the occurrence of 23 species and to infer their phylogenetic relationships. These analyses confirmed the identity of six species previously cited for Brazil: Gelidiella acerosa, G. ligulata, Gelidium crinale, G. floridanum, Pterocladiella bartlettii and P. capillacea. Three new reports for Brazil were also detected: Gelidium microdonticum, Pterocladiella beachiae and P. australafricanensis. Fourteen species remain unidentified and require detailed morphological evaluation.