PIGMENT SUITES AND TAXONOMIC GROUPS IN PRASINOPHYCEAE1

Pigment analysis performed on 30 Prasinophyceae strains revealed two main groups: the prasinoxanthin‐containing and prasinoxanthin‐less Prasinophyceae. Prasinoxanthin‐containing Prasinophyceae comprised the orders Mamiellales, Pseudoscourfieldiales (Pycnococcaceae), and Prasinococcales. For this group, classification with pigment composition showed a good agreement with molecular phylogeny. Mamiellales, except Crustomastix stigmatica, accumulated uriolide, micromonal, dihydrolutein, and the pigment Unidentified M1 as characteristic pigments. Prasinococcales and Pseudoscourfieldiales (Pycnococcaceae) lacked micromonal and Unidentified M1. In addition, Pseudoscourfieldiales (Pycnococcaceae) lacked uriolide. A chl c₃‐like pigment was present in prasinoxanthin‐containing strains isolated from the deep sea. Common green algae pigments, a loroxanthin derivative, and siphonaxanthin plus derivatives were found in the prasinoxanthin‐less Prasinophyceae, which included strains from Pyramimonadales, Pseudoscourfieldiales (Nephroselmidiaceae), Chlorodendrales, and a new order. Although some associations could be observed, the correspondence between pigments and molecular taxonomy was less clear for this group.     

Phylogeny and taxonomy of the Raphidophyceae (Heterokontophyta) and Chlorinimonas sublosa gen. et sp. nov., a new marine sand-dwelling raphidophyte

A new flagellate of the Raphidophyceae, Chlorinimonas sublosa gen. et sp. nov., collected from Wakayama Prefecture, Japan is described based on morphological observations, microspectrophotometry of chloroplasts, and phylogenetic analysis of SSU rDNA sequences. The cell was usually elliptical, sometimes spherical, oval or slender, and possessed two subequal heterodynamic flagella emerging from a subapical pit. Greenish yellow discoidal chloroplasts, 15–25 per cell, were situated at the periphery of the cell. The alga is very similar to the genus Heterosigma, but distinct in that there is no invagination of thylakoids into the pyrenoids and no typical girdle lamella in the chloroplast, and the chloroplasts are greenish yellow. Phylogenetic analysis of SSU rDNA revealed that this alga forms a sister clade with the clade of Chattonella and Heterosigma. Based on these results, we propose a new genus Chlorinimonas with Chlorinimonas sublosa as the type species. In addition, this paper is the first report of molecular data covering all genera of the Raphidophyceae. The phylogenetic analysis suggests that the intrusion to freshwater habitat has occurred only once in the Raphidophyceae.     

PHYLOGENY OF ZYGNEMOPHYCEAE BASED ON COXIII GENE SEQUENCE DATA

Molecular phylogenetic analysis of the conjugating green algae (Class Zygnemophyceae) using nuclear (SSU rDNA) and chloroplast (rbcL) gene sequences has resolved hypotheses of relationship at the class, order, and family levels, but several key questions will require data from additional genes. Based on SSU and rbcL sequences, the Zygnemophyceae and Desmidiales are monophyletic, and families of placoderm desmids are distinct clades (Desmidiaceae, Peniaceae, Closteriaceae, and Gonatozygaceae). In contrast, the Zygnemataceae and Mesotaeniaceae are paraphyletic, although whether these two traditional families constitute a clade is uncertain. In addition, relationships of genera within families have proven resistant to resolution with these two oft‐used genes. We have sequenced the coxIII gene from the mitochondrial genome to address some of these ambiguous portions of the phylogeny of conjugating green algae. The coxIII gene is more variable than rbcL or SSU rDNA and offers greater resolving power for relationships of genera. We present preliminary analyses of coxIII sequences from each of the traditional families of Zygnemophyceae and contrast the resulting topologies with those derived from nuclear and chloroplast genes.     

Cryptic Speciation in the Genus Cryptoglena (Euglenaceae) Revealed by Nuclear and Plastid SSU and LSU rRNA Gene

The photosynthetic euglenoid genus Cryptoglena is differentiated from other euglenoid genera by having a longitudinal sulcus, one chloroplast, two large trough‐shaped paramylon plates positioned between the chloroplast and pellicle, and lack of metaboly. The genus contains only two species. To understand genetic diversity and taxonomy of Cryptoglena species, we analyzed molecular and morphological data from 25 strains. A combined data set of nuclear SSU and LSU and plastid SSU and LSU rRNA genes was analyzed using Bayesian, maximum likelihood, maximum parsimony, and distance (neighbor joining) methods. Although morphological data of all strains showed no significant species‐specific pattern, molecular data segregated the taxa into five clades, two of which represented previously known species: C. skujae and C. pigra, and three of which were designated as the new species, C. soropigra, C. similis, and C. longisulca. Each species had unique molecular signatures that could be found in the plastid SSU rRNA Helix P23_1 and LSU rRNA H2 domain. The genetic similarity of intraspecies based on nr SSU rDNA ranged from 97.8% to 100% and interspecies ranged from 95.3% to 98.9%. Therefore, we propose three new species based on specific molecular signatures and gene divergence of the nr SSU rDNA sequences.     

GRACILARIOPSIS MCLACHLANII SP. NOV. AND GRACILARIOPSIS PERSICA SP. NOV. OF THE GRACILARIACEAE (GRACILARIALES,RHODOPHYCEAE) FROM THE INDIAN OCEAN1

Two new species of Gracilariopsis from the Indian Ocean are proposed—Gracilariopsis (Gp.) mclachlanii Buriyo, Bellorin et M. C. Oliveira sp. nov. from Tanzania and Gracilariopsis persica Bellorin, Sohrabipour et E. C. Oliveira sp. nov. from Iran—based on morphology and DNA sequence data (rbcL gene and SSU rDNA). Both species fit the typical features of Gracilariopsis: axes cylindrical throughout, freely and loosely ramified up to four orders, with an abrupt transition in cell size from medulla to cortex, cystocarps lacking tubular nutritive cells and superficial spermatangia. Nucleotide sequence comparisons of rbcL and SSU rDNA placed both species into the Gracilariopsis clade as distinct species from all the accepted species for this genus, forming a deeply divergent lineage together with some species from the Pacific. The new species are very difficult to distinguish on morphological grounds from other species of Gracilariopsis, stressing the importance of homologous molecular marker comparisons for the species recognition in this character‐poor genus.     

Morphology,ultrastructure, and molecular phylogeny of Wangodinium sinense gen. et sp. nov. (Gymnodiniales,Dinophyceae) and revisiting of Gymnodinium dorsalisulcum and Gymnodinium impudicum

The genus Gymnodinium includes many morphologically similar species, but molecular phylogenies show that it is polyphyletic. Eight strains of Gymnodinium impudicum, Gymnodinium dorsalisulcum and a novel Gymnodinium‐like species from Chinese and Malaysian waters and the Mediterranean Sea were established. All of these strains were examined with light microscopy, scanning electron microscopy and transmission electron microscopy. SSU, LSU and internal transcribed spacers rDNA sequences were obtained. A new genus, Wangodinium, was erected to incorporate strains with a loop‐shaped apical structure complex (ASC) comprising two rows of amphiesmal vesicles, here referred to as a new type of ASC. The chloroplasts of Wangodinium sinense are enveloped by two membranes. Pigment analysis shows that peridinin is the main accessory pigment in W. sinense. Wangodinium differs from other genera mainly in its unique ASC, and additionally differs from Gymnodinium in the absence of nuclear chambers, and from Lepidodinium in the absence of Chl b and nuclear chambers. New morphological information was provided for G. dorsalisulcum and G. impudicum, e.g., a short sulcal intrusion in G. dorsalisulcum; nuclear chambers in G. impudicum and G. dorsalisulcum; and a chloroplast enveloped by two membranes in G. impudicum. Molecular phylogeny was inferred using maximum likelihood and Bayesian inference with independent SSU and LSU rDNA sequences. Our results support the classification of Wangodinium within the Gymnodiniales sensu stricto clade and it is close to Lepidodinium. Our results also support the close relationship among G. dorsalisulcum, G. impudicum, and Barrufeta. Further research is needed to assign these Gymnodinium species to Barrufeta or to erect new genera.     

Serial replacement of a diatom endosymbiont in the marine dinoflagellate Peridinium quinquecorne (Peridiniales, Dinophyceae)

To infer the phylogeny of both the host and the endosymbiont of Peridinium quinquecorne Abé, the small subunit (SSU) ribosomal DNA (rDNA) from the host and two genes of endosymbiont origin (plastid‐encoded rbcL and nuclear‐encoded SSU rDNA) were determined. The phylogenetic analysis of the host revealed that the marine dinoflagellate P. quinquecorne formed a clade with other diatom‐harbouring dinoflagellates, including Kryptoperidinium foliaceum (Stein) Lindeman, Durinskia baltica (Levander) Carty et Cox and Galeidinium rugatum Tamura et Horiguchi, indicating a single endosymbiotic event for this lineage. Phylogenetic analyses of the endosymbiont in these organisms revealed that the endosymbiont of P. quinquecorne formed a clade with a centric diatom (SSU data indicated it to be closely related to Chaetoceros), whereas the endosymbionts of other three dinoflagellates formed a clade with a pennate diatom. The discrepancy between the host and the endosymbiont phylogenies suggests a secondary replacement of the endosymbiont from a pennate to a centric diatom in P. quinquecorne.     

TWO NEW AUSTRALIAN SPECIES OF PREDAEA (NEMASTOMATACEAE,RHODOPHYTA) WITH TAXONOMIC RECOMMENDATIONS FOR AN EMENDED NEMASTOMATALES AND EXPANDED HALYMENIALES1

Two new species of the red algal genus Predaea are described from Australia. The first, Predaea aurora Kraft et G.W. Saunders, sp. nov., is unusual in its cool‐temperate distribution and in a number of anatomical attributes, most notably the rhizoid‐like habit of the nutritive filaments associated with the auxiliary cells. The second species, Predaea tumescens Kraft et G.W. Saunders, sp. nov., inhabits a coral reef habitat more typical of the genus but nonetheless differs in a number of anatomical details from other reported species. Nuclear small subunit rDNA sequences have confirmed the affinity of P. aurora to other species currently included in this genus. Molecular analyses further indicate that Predaea belongs in the Nemastomataceae and that the Nemastomataceae and Schizymeniaceae are sister taxa in an independent clade of “lineage 4” florideophyte algae. As such, a proposal is made to resurrect the Nemastomatales Kylin emend. G.W. Saunders et Kraft to accommodate these two families. Within the Schizymeniaceae, the Australian‐endemic Platoma australicum and Platoma foliosum were only distantly related to the other included Platoma, Schizymenia, and Titanophora spp. We therefore propose Wetherbeella G.W. Saunders et Kraft, gen. nov., to accommodate these two species. An additional outcome of our molecular analyses is that the genus Tsengia is not a member of the Nemastomataceae (where it is currently placed) but rather forms an independent lineage in the Halymeniales that we now designate as the Tsengiaceae G.W. Saunders et Kraft, fam. nov. Finally, the South African Nemastoma lanceolatum J. Agardh is transferred to Tsengia.     

GENETIC VARIABILITY AND MOLECULAR PHYLOGENY OF DINOPHYSIS SPECIES (DINOPHYCEAE) FROM NORWEGIAN WATERS INFERRED FROM SINGLE CELL ANALYSES OF rDNA1

The objectives of this study were to determine rDNA sequences of the most common Dinophysis species in Scandinavian waters and to resolve their phylogenetic relationships within the genus and to other dinoflagellates. A third aim was to examine the intraspecific variation in D. acuminata and D. norvegica, because these two species are highly variable in both morphology and toxicity. We obtained nucleotide sequences of coding (small subunit [SSU], partial large subunit [LSU], 5.8S) and noncoding (internal transcribed spacer [ITS]1, ITS2) parts of the rRNA operon by PCR amplification of one or two Dinophysis cells isolated from natural water samples. The three photosynthetic species D. acuminata, D. acuta, and D. norvegica differed in only 5 to 8 of 1802 base pairs (bp) within the SSU rRNA gene. The nonphotosynthetic D. rotundata (synonym Phalacroma rotundatum[Claparède et Lachmann] Kofoid et Michener), however, differed in approximately 55 bp compared with the three photosynthetic species. In the D1 and D2 domains of LSU rDNA, the phototrophic species differed among themselves by 3 to 12 of 733 bp, whereas they differed from D. rotundata by more than 100 bp. This supports the distinction between Dinophysis and Phalacroma. In the phylogenetic analyses based on SSU rDNA, all Dinophysis species were grouped into a common clade in which D. rotundata diverged first. The results indicate an early divergence of Dinophysis within the Dinophyta. The LSU phylogenetic analyses, including 4 new and 11 Dinophysis sequences from EMBL, identified two major clades within the phototrophic species. Little or no intraspecific genetic variation was found in the ITS1–ITS2 region of single cells of D. norvegica and D. acuminata from Norway, but the delineation between these two species was not always clear.     

PHYLOGENETIC ANALYSIS OF THE GENUS EUGLENA (EUGLENOPHYCEAE) WITH PARTICULAR REFERENCE TO THE TYPE SPECIES EUGLENA VIRIDIS1

Euglena viridis (subgenus Euglena) serves as the type species for the genus Euglena. In this study, molecular phylogenetic analyses using a small subunit (SSU) and a combined SSU–partial large subunit rDNA data set for members of the genus Euglena showed that strains identified as E. viridis on the basis of morphology are distributed between two separate nonsister clades. Although all the E. viridis strains examined were morphologically indistinguishable and possessed spherical mucocysts and stellate chloroplasts with one paramylon center, there was a high degree of sequence divergence between the E. viridis strains in different clades, making this a cryptic species. Like E. viridis, all taxa from the subgenus Euglena are characterized by having one or more stellate chloroplasts with paramylon grains clustered around the center of the chloroplast. These additional taxa were divided into four clades in all the molecular analyses. Strains of Euglena stellata formed two nonsister clades whose members had a single aggregate chloroplast with paramylon center and spindle‐shaped mucocysts. A geniculata clade included species with one or two stellate chloroplasts with paramylon centers and spherical mucocysts, and the cantabrica clade had members with one stellate chloroplast with paramylon center and spherical mucocysts often arranged in spiral rows. Interspersed among these were three additional clades bearing taxa from the subgenus Calliglena that contains members with discoid plastids and pyrenoids that may or may not be capped with paramylon. These taxa formed a laciniata clade, mutabilis clade, and gracilis clade. This study demonstrates that E. viridis and E. stellata are cryptic species that can only be distinguished at the molecular level. Because E. viridis is the designated type species for the genus Euglena, we designated an epitype for E. viridis.     

PHYLOGENETIC AFFINITIES OF “CHANTRANSIA” STAGES IN MEMBERS OF THE BATRACHOSPERMALES AND THOREALES (RHODOPHYTA)1

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.     

MORPHOLOGICAL AND GENETIC CHARACTERIZATION OF PHAEOCYSTIS CORDATA AND P. JAHNII (PRYMNESIOPHYCEAE), TWO NEW SPECIES FROM THE MEDITERRANEAN SEA

Two new Phaeocystis species recently discovered in the Mediterranean Sea are described using light and electron microscopy, and their systematic position is discussed on the basis of an analysis of their nuclear-encoded small-subunit ribosomal RNA gene (SSU rRNA) sequences. Phaeocystis cordata Zingone et Chrétiennot-Dinet was observed only as flagellated unicells. Cells are heart shaped, with two flagella of slightly unequal length and a short haptonema. The cell body is covered with two layers of thin scales. The outermost layer scales are oval, with a faint radiating pattern, a raised rim, and a modest central knob. The inner-layer scales are smaller and have a faint radiate pattern and an inflexed rim. Cells swim with their flagella close together, obscuring the haptonema, pushing the cell, and causing it to rotate about its longitudinal axis while moving forward. Phaeocystis jahnii Zingone was isolated as a nonmotile colony. It forms loose aggregates of cells embedded in a mucilaginous, presumably polysaccharide matrix without a definite shape or visible external envelope. The flagellated stage has the features typical of other Phaeocystis species. Cells are rounded in shape and slightly larger than P. cordata. The cell body is covered with extremely thin scales of two different sizes with a very faint radiating pattern toward their margin. Swimming behavior is similar to that of P. cordata, with the flagella in a posterior position as the cells swim. The SSU rRNA sequence analysis indicated that both species are distinct from other cultivated Phaeocystis species sequenced to date. Regions previously identified as specific for the genus Phaeocystis are not found in P. jahnii, and new genus-specific regions have been identified. P. cordata is more closely related to the colonial species P. globosa, P. antarctica, and P. pouchetii and has branched prior to the divergence of the warm-water P. globosa species complex from the cold-water species P. antarctica and P. pouchetii. These results are discussed within a framework ofthe available data on the evolution of the world’s oceans.     

A COMBINED 18S rDNA AND rbcL PHYLOGENETIC ANALYSIS OF CHLOROMONAS AND CHLAMYDOMONAS (CHLOROPHYCEAE,VOLVOCALES) EMPHASIZING SNOW AND OTHER COLD‐TEMPERATURE HABITATS1

An extensive phylogenetic analysis of the biflagellate genera, Chlamydomonas Ehrenberg and Chloromonas Gobi emend. Wille, was undertaken using 18S rDNA and rbcL gene sequence analysis. Emphasis was placed on 21 cold‐tolerant taxa of which 10 are from snow. These taxa occurred in four distinct clades each in the 18S rDNA and rbcL phylogenies, and when taken together suggest at least five distinct origins in cold habitats. Most of these taxa occur in a single clade (A), and all snow species occurred in this clade. In the rbcL and combined rbcL–18S rDNA analyses, the snow taxa fell into three groups. Two groups occurred in subclade 1: Chlamydomonas augustae Skuja CU, Chlamydomonas augustae UTEX, and Chlamydomonas sp.‐A and Chloromonas clathrata Korshikov, Chloromonas rosae Ettl CU, and Chloromonas rosae v. psychrophila var. nov. The third snow group, subclade 2, included three species with unique cell divisions, Chloromonas brevispina (Fritsch) Hoham, Roemer et Mullet, Chloromonas pichinchae (Lagerheim) Wille, and Chloromonas sp.‐D, and the basal Chloromonas nivalis (Chodat) Hoham et Mullet with normal cell divisions. This suggests that the snow habitat has been colonized at least twice and possibly three times in the history of these biflagellates. In the 18S rDNA tree, one cold‐tolerant Chloromonas species fell outside clade A: Chloromonas subdivisa (Pascher et Jahoda) Gerloff et Ettl. In the rbcL tree, three cold‐tolerant Chloromonas species fell outside clade A: Chloromonas subdivisa, Chloromonas sp.‐ANT1, and Chloromonas sp.‐ANT3. These results support previous findings that pyrenoids have been gained and lost several times within this complex.     

ISOLATION AND CHARACTERIZATION OF PARMALES (HETEROKONTA/HETEROKONTOPHYTA/STRAMENOPILES) FROM THE OYASHIO REGION,WESTERN NORTH PACIFIC1

A small siliceous species of marine phytoplankton, order Parmales (Heterokonta), was isolated and characterized for the first time with the aid of a fluorescent silicon tracer 2‐(4‐pyridyl)‐5‐([4‐(2‐dimethylaminoethylaminocarbamoyl)‐methoxy]phenyl)oxazole (PDMPO). This dye was easily detected by clear fluorescence in newly produced silica cell plates. Our isolate was surrounded by eight smooth plates without any ornamentation, suggesting a similarity to Triparma laevis B. C. Booth. TEM observation showed the typical ultrastructure of photosynthetic heterokontophytes; with two chloroplast endoplasmic reticulate membranes, a girdle lamella, three thylakoid lamellae, and mitochondrion with tubular cristae. Molecular phylogenetic analyses of SSU rDNA and rbcL genes showed that the parmalean alga was within the bolidophycean clade of autotrophic naked flagellates and a sister group of diatoms. HPLC analysis detected chl a, c₁ + c₂, and c₃; fucoxanthin; and diadinoxanthin as major photosynthetic pigments, and a composition that is shared with Bolidophyceae and diatoms. Together, these data indicate a close evolutionary relationship between Parmales, Bolidophyceae, and diatoms. The PDMPO‐staining procedure should accelerate isolation of other Parmales species, helping to establish their diversity and aiding quantitative study of their role in oceanic processes.     

MOLECULAR PHYLOGENY AND REVISION OF THE GENUS NETRIUM (ZYGNEMATOPHYCEAE,STREPTOPHYTA): NUCLEOTAENIUM GEN. NOV.1

Nuclear‐encoded SSU rDNA, chloroplast LSU rDNA, and rbcL genes were sequenced from 53 strains of conjugating green algae (Zygnematophyceae, Streptophyta) and used to analyze phylogenetic relationships in the traditional order Zygnematales. Analyses of a concatenated data set (5,220 nt) established 12 well‐supported clades in the order; seven of these constituted a superclade, termed “Zygnemataceae.” Together with genera (Zygnema, Mougeotia) traditionally placed in the family Zygnemataceae, the “Zygnemataceae” also included representatives of the genera Cylindrocystis and Mesotaenium, traditionally placed in the family Mesotaeniaceae. A synapomorphic amino acid replacement (codon 192, cysteine replaced by valine) in the LSU of RUBISCO characterized this superclade. The traditional genera Netrium, Cylindrocystis, and Mesotaenium were shown to be para‐ or polyphyletic, highlighting the inadequacy of phenotypic traits used to define these genera. Species of the traditional genus Netrium were resolved as three well‐supported clades each distinct in the number of chloroplasts per cell, their surface morphology (structure and arrangement of lamellae) and the position of the nucleus or nuclear behavior during cell division. Based on molecular phylogenetic analyses and synapomorphic phenotypic traits, the genus Netrium has been revised, and a new genus, Nucleotaenium gen. nov., was established. The genus Planotaenium, also formerly a part of Netrium, was identified as the sister group of the derived Roya/Desmidiales clade and thus occupies a key position in the evolutionary radiation leading to the most species‐rich group of streptophyte green algae.     

Brandtia ciliaticola gen. et sp. nov. (Chlorellaceae,Trebouxiophyceae) a common symbiotic green coccoid of various ciliate species

Many freshwater protists harbor unicellular green algae within their cells and these host‐symbiont relationships slowly are becoming better understood. Recently, we reported that several ciliate species shared a single species of symbiotic algae. Nonetheless, the algae from different host ciliates were each distinguishable by their different genotypes, and these host‐algal genotype combinations remained unchanged throughout a 15‐month period of sampling from natural populations. The same algal species had been reported as the shared symbiont of several ciliates from a remote lake. Consequently, this alga appears to play a key role in ciliate‐algae symbioses. In the present study, we successfully isolated the algae from ciliate cells and established unialgal cultures. This species is herein named Brandtia ciliaticola gen. et sp. nov. and has typical ‘Chlorella‐like’ morphology, being a spherical autosporic coccoid with a single chloroplast containing a pyrenoid. The alga belongs to the Chlorella‐clade in Chlorellaceae (Trebouxiophyceae), but it is not strongly connected to any of the other genera in this group. In addition to this phylogenetic distinctiveness, a unique compensatory base change in the SSU rRNA gene is decisive in distinguishing this genus. Sequences of SSU‐ITS (internal transcribed spacer) rDNA for each isolate were compared to those obtained previously from the same host ciliate. Consistent algal genotypes were recovered from each host, which strongly suggests that B. ciliaticola has established a persistent symbiosis in each ciliate species.     

Lineage-specific variations of congruent evolution among DNA sequences from three genomes,and relaxed selective constraints on <Emphasis Type="Italic">rbc</Emphasis>L in <Emphasis Type="Italic">Cryptomonas</Emphasis> (Cryptophyceae)

Background  

Plastid-bearing cryptophytes like Cryptomonas contain four genomes in a cell, the nucleus, the nucleomorph, the plastid genome and the mitochondrial genome. Comparative phylogenetic analyses encompassing DNA sequences from three different genomes were performed on nineteen photosynthetic and four colorless Cryptomonas strains. Twenty-three rbc L genes and fourteen nuclear SSU rDNA sequences were newly sequenced to examine the impact of photosynthesis loss on codon usage in the rbc L genes, and to compare the rbc L gene phylogeny in terms of tree topology and evolutionary rates with phylogenies inferred from nuclear ribosomal DNA (concatenated SSU rDNA, ITS2 and partial LSU rDNA), and nucleomorph SSU rDNA.     

CERAMIUM INKYUII SP. NOV. (CERAMIACEAE,RHODOPHYTA) FROM KOREA: A NEW SPECIES BASED ON MORPHOLOGICAL AND MOLECULAR EVIDENCE1

Ceramium inkyuii sp. nov. is newly described based on samples collected from the east coast of Korea and compared with similar species such as C. paniculatum and C. tenerrimum. The new species is characterized by pseudo‐dichotomously branched thalli with a twist in the upper part, a single row of spines on the abaxial side, strongly inrolled apices, and the presence of gland cells. In contrast, C. paniculatum has alternate branches and lacks gland cells, and C. tenerrimum is spineless and also lacks gland cells. Ceramium inkyuii was observed to be an annual species producing tetrasporangia in the spring to summer and cystocarps in the fall. Plastid‐encoded rbcL and nuclear small subunit (SSU) rDNA sequences were determined in four samples of C. inkyuii from different locations and six samples of four putative relatives. All four C. inkyuii replicates from three different locations had identical sequences of each gene, and the interspecific sequence divergences were enough to warrant its natural entity. The phylogenies of the rbcL and SSU rDNA sequences also indicate the monophyly of C. inkyuii. The spinous C. inkyuii was more closely related to the spineless C. tenerrimum than to the spinous C. paniculatum.     

Investigation of a freshwater acrochaetioid alga (Rhodophyta) with molecular and morphological methods

An enigmatic acrochaetioid alga was collected from Niangziguan spring in Shanxi Province, northern China. Morphological data indicated that this alga reproduces exclusively asexually by monosporangia and its morphological characteristics suggested that it might be referred to Audouinella heterospora. To ascertain its phylogenetic position, phylogenetic trees were reconstructed using partial sequences of the plastid‐encoded gene (rbcL) and the nuclear‐encoded gene (SSU rDNA) applying Bayesian inference (BI), maximum parsimony (MP) and maximum likelihood (ML). However, phylogenetic reconstructions showed that this acrochaetioid alga does not belong in a clade with the genus Audouinella, but forms a clade with Thorea hispida (Thoreales). Based on this analysis it is concluded that A. heterospora represents the ‘chantransia’ stage of T. hispida.     

Verrucophora farcimen gen. et sp. nov. (Dictyochophyceae,Heterokonta)—a bloom‐forming ichthyotoxic flagellate from the Skagerrak,Norway1

Since 1998, a heterokont flagellate initially named Chattonella aff. verruculosa has formed recurrent extensive blooms in the North Sea and the Skagerrak, causing fish mortalities. Cells were isolated from the 2001 bloom off the south coast of Norway, and monoalgal cultures were established and compared with the Chattonella verruculosa Y. Hara et Chihara reference strain NIES 670 from Japan. The cells in Norwegian cultured isolates were very variable in size and form, being large oblong (up to 34 μm long) to small rounded (5–9 μm in diameter) with two unequal flagella, numerous chloroplasts, and mucocysts. The SSU and partial LSU rDNA sequences of strains from Norway and Japan were compared and differed by 0.4% (SSU) and 1.3% (LSU), respectively. Five strains from Norway were identical in the LSU rDNA region. Phylogenetic analyses based on heterokont SSU and concatenated SSU + LSU rDNA sequences placed C. aff. verruculosa and the Japanese C. verruculosa within the clade of Dictyochophyceae, with the picoflagellate Florenciella parvula Eikrem as the closest relative. Ultrastructure, morphology, and pigment composition supported this affinity. We propose the name Verrucophora farcimen sp. et gen. nov. for this flagellate and systematically place it within the class Dictyochophyceae. Our studies also show that C. verruculosa from Japan is genetically and morphologically different but closely related to V. farcimen. The species is transferred from the class Raphidophyceae to the class Dictyochophyceae and renamed Verrucophora verruculosa. We propose a new order, Florenciellales, to accommodate V. farcimen, V. verruculosa, and F. parvula.