Cyst‐motile stage relationship,morphology, ultrastructure,and molecular phylogeny of the gymnodinioid dinoflagellate Barrufeta resplendens comb. nov., formerly known as Gyrodinium resplendens,isolated from the Gulf of Mexico

In the present study, we redescribed Gyrodinium resplendens through incubation of process bearing cysts extracted from sediment collected in the northern Gulf of Mexico. The morphology and ultrastructure of the motile stage and cyst stage were examined using light microscopy, scanning electron microscopy, and transmission electron microscopy and this revealed that the species should be transferred to the genus Barrufeta. This genus differs from other gymnodinioid genera in possessing a Smurf‐cap apical structure complex (ASC) and currently encompasses only one species, Barrufeta bravensis. B. resplendens shows a Smurf‐cap ASC that consists of three rows of elongated vesicles with small knobs in the middle one. B. resplendens is very similar to B. bravensis in cell morphology, but can be separated using the ultrastructure such as the shape and location of nucleus and pyrenoids, which highlights the importance of ultrastructure at inter‐specific level in the genus Barrufeta. The unique cysts of B. resplendens are brown and process bearing, and have a tremic archeopyle with a zigzag margin on the dorsal side of the epicyst, and not polar as in cysts of Polykrikos. The cysts do not survive the palynological treatment used here and probably have a wide distribution. Maximum‐likelihood and Bayesian inference were carried out based on partial large subunit ribosomal DNA (LSU rDNA) sequences. Molecular phylogeny supports that the genus Barrufeta is monophyletic, and that the genus Gymnodinium is polyphyletic. Our results suggest that details of the ASC together with ultrastructure are potential features to subdivide the genus Gymnodinium.     

Description of the Halophile Euplotes qatarensis nov. spec. (Ciliophora,Spirotrichea, Euplotida) Isolated from the Hypersaline Khor Al‐Adaid Lagoon in Qatar

The morphology, ontogenesis, and phylogenetic relationships of a halophile euplotid ciliates, Euplotes qatarensis nov. spec., isolated from the Khor Al‐Adaid Lagoon in Qatar were investigated based on live observation as well as protargol‐ and silver nitrate‐impregnated methods. The new species is characterised by a combination of features: the halophile habitat, a cell size of 50–65 × 33–40 μm, seven dorsal ridges, 10 commonly sized frontoventral cirri, two widely spaced marginal cirri, 10 dorsolateral kineties, and a double silverline pattern. The morphogenesis is similar to that of its congeners: (i) the oral primordium develops hypoapokinetally and the parental oral apparatus is retained; (ii) the frontoventral‐transverse field of five streaks gives rise to the frontal, ventral, and transverse cirri, but not to the cirri I/1 and the marginal cirri; (iii) the dorsal somatic ciliature develops by intrakinetal proliferation of basal bodies in two anlagen per kinety that are just anterior and posterior to the future division furrow; (iv) the caudal cirri are formed by the two rightmost dorsolateral kineties. The SSU rDNA sequence of E. qatarensis branches with full support in the Euplotopsis elegans–Euplotes nobilii–Euplotopsis raikovi clade. The closest related publicly available SSU rDNA sequence is the one of E. nobilii, with which E. qatarensis has 93.4% sequence similarity. Euplotes parawoodruffi Song & Bradbury, 1997 is transferred to the genus Euplotoides based on the absence of frontoventral cirrus VI/3.     

Molecular phylogeny and taxonomic revision of the genus Wittrockiella (Pithophoraceae,Cladophorales), including the descriptions of W. australis sp. nov. and W. zosterae sp. nov.

Wittrockiella is a small genus of filamentous green algae that occurs in habitats with reduced or fluctuating salinities. Many aspects of the basic biology of these algae are still unknown and the phylogenetic relationships within the genus have not been fully explored. We provide a phylogeny based on three ribosomal markers (ITS, LSU, and SSU rDNA) of the genus, including broad intraspecific sampling for W. lyallii and W. salina, recommendations for the use of existing names are made, and highlight aspects of their physiology and life cycle. Molecular data indicate that there are five species of Wittrockiella. Two new species, W. australis and W. zosterae, are described, both are endophytes. Although W. lyallii and W. salina can be identified morphologically, there are no diagnostic morphological characters to distinguish between W. amphibia, W. australis, and W. zosterae. A range of low molecular weight carbohydrates were analyzed but proved to not be taxonomically informative. The distribution range of W. salina is extended to the Northern Hemisphere as this species has been found in brackish lakes in Japan. Furthermore, it is shown that there are no grounds to recognize W. salina var. kraftii, which was described as an endemic variety from a freshwater habitat on Lord Howe Island, Australia. Culture experiments indicate that W. australis has a preference for growth in lower salinities over full seawater. For W. amphibia and W. zosterae, sexual reproduction is documented, and the split of these species is possibly attributable to polyploidization.     

Euchlorocystis gen. nov. and Densicystis gen. nov., Two New Genera of Oocystaceae Algae from High‐altitude Semi‐saline Habitat (Trebouxiophyceae,Chlorophyta)

The Oocystaceae family is generally considered to contain common freshwater eukaryotic microalgae, and few are reported living in semi‐saline habitats. Our latest ecological survey in Qinghai Lake and Angzicuo Lake, both large, closed, high‐altitude, semi‐saline lakes located on the Qinghai‐Tibet plateau in China, revealed Oocystaceae species as a dominant group among plankton. Since limited knowledge exists about semi‐saline species in the Oocystaceae family, a taxonomical study was carried out using morphological and phylogenetic methods. Using this approach, four new strains of Oocystaceae were identified and successfully cultured in the lab. Molecular results correlated with morphological characters and resolved these species into at least three genera. A new genus, Euchlorocystis, with type species Euchlorocystis subsalina, is described here as having the distinctive morphology of multiple pyrenoids per chloroplast among Oocystaceae, and an independent phylogenetic position at the base of the Oocystaceae. Similarly, the genus Densicystis, with type species Densicystis glomerata, is newly proposed here as having a unique colony morphology of dozens or hundreds of little cells tightly embedded in ellipsoid to round mucilage masses. Oocystis marina, originally described from the Baltic Sea, was also identified in Qinghai Lake and Angzicuo Lake and phylogenetically positioned in the semi‐saline clade of the Oocystaceae. The result that a marine species was detected in the closed inland lakes implies a further need to reevaluate the origins of these species.     

Taxonomic revision of Chlamydomonas subg. Amphichloris (Volvocales,Chlorophyceae), with resurrection of the genus Dangeardinia and descriptions of Ixipapillifera gen. nov. and Rhysamphichloris gen. nov.

Chlamydomonas (Cd.) is one of the largest but most polyphyletic genera of freshwater unicellular green algae. It consists of 400–600 morphological species and requires taxonomic revision. Toward reclassification, each morphologically defined classical subgenus (or subgroup) should be examined using culture strains. Chlamydomonas subg. Amphichloris is characterized by a central nucleus between two axial pyrenoids, however, the phylogenetic structure of this subgenus has yet to be examined using molecular data. Here, we examined 12 strains including six newly isolated strains, morphologically identified as Chlamydomonas subg. Amphichloris, using 18S rRNA gene phylogeny, light microscopy, and mitochondria fluorescent microscopy. Molecular phylogenetic analyses revealed three independent lineages of the subgenus, separated from the type species of Chlamydomonas, Cd. reinhardtii. These three lineages were further distinguished from each other by light and fluorescent microscopy—in particular by the morphology of the papillae, chloroplast surface, stigmata, and mitochondria—and are here assigned to three genera: Dangeardinia emend., Ixipapillifera gen. nov., and Rhysamphichloris gen. nov. Based on the molecular and morphological data, two to three species were recognized in each genus, including one new species, I. pauromitos. In addition, Cd. deasonii, which was previously assigned to subgroup “Pleiochloris,” was included in the genus Ixipapillifera as I. deasonii comb. nov.     

New freshwater diatom genus,Edtheriotia gen. nov. of the Stephanodiscaceae (Bacillariophyta) from south‐central China

We describe a new genus and species of the diatom family Stephanodiscaceae with light and scanning electron microscopy from Libo Small Hole, Libo County, Guizhou Province, China. Edtheriotia guizhoiana gen. & sp. nov. has striae across the valve face of varying lengths, and are composed of fine striae towards the margin and onto the mantle. Many round to stellate siliceous nodules cover the exterior of the valve. External fultoportulae opening are short tubes; the opening of the rimportula lacks a tube. Internally a hyaline rim is positioned near the margin. Marginal fultoportulae possess two arcuate opercles. Areolae have domed cribra on the valve face. Those near the margin do not open to the interior. One to three sessile to slightly‐raised rimportulae are placed on the valve face towards the margin; they do not terminate shortened striae towards the center of the valve. This suite of features distinguishes this group from other known genera in the Stephanodicaeae. Cyclotella shanxiensis is transferred to Edtheriotia, making the new combination E. shanxiensis (Xie & Qi) Kociolek et al. comb. nov. It differs from E. guizhoiana by the presence of open pores near the margin of the valve. Features of the new genus are compared and contrasted with others in the Family Stephanodiscaceae. The two species of the genus, unlike most in the family, are known only from rivers and ponds from China and Japan.     

Pinjata ruminata gen. et sp. n.—A New Member of Centrohelid Family Yogsothothidae (Haptista: Centroplasthelida) from the Brackish River

A new genus and species of centrohelid heliozoan Pinjata ruminata from the Tuzlukkol’ River (Orenburg Region of Russia) and Gor?koe Lake (Chelyabinsk Region of Russia) is studied with light‐ and electron microscopy. Pinjata ruminata has two types of plate scales, partially running up the sides of the axopodia. Inner plate scales (3.2–4.9 × 1.5–2.6 μm) are flat, ovate‐oblong and have a broad axial thickening and a thin electron‐dense border. Outer plate scales (4.2–6.7 × 1.5–3.0 μm) are concave, elongated, of irregular shape, often curved, and broadened towards one end. Roundish depressions are forming two rows on both sides of the narrow axial thickening. The cells are attached to the substratum. Molecular phylogenetic analysis based on the SSU rDNA robustly placed P. ruminata in the family Yogsothothidae. This position is confirmed with the presence of five panacanthocystid increase regions. The morphology of the new genus is in a good accordance with diagnosis of the family. The status of a genus “Heteroraphidiophrys” is discussed. Other potential findings of Pinjata from literature are analyzed. Pinjata represents the third lineage of centrohelids, characterized with the presence of only tangentially oriented plate scales. The halophilic nature of Yogsothothidae is suggested.     

Wilsonosiphonia gen. nov. (Rhodomelaceae,Rhodophyta) based on molecular and morpho‐anatomical characters

Morphological, anatomical, and molecular sequence data were used to assess the establishment and phylogenetic position of the genus Wilsonosiphonia gen. nov. Phylogenies based on rbcL and concatenated rbcL and cox1 loci support recognition of Wilsonosiphonia gen. nov., sister to Herposiphonia. Diagnostic features for Wilsonosiphonia are rhizoids located at distal ends of pericentral cells and taproot‐shaped multicellular tips of rhizoids. Wilsonosiphonia includes three species with diagnostic rbcL and cox1 sequences, Wilsonosiphonia fujiae sp. nov. (the generitype), W. howei comb. nov., and W. indica sp. nov. These three species resemble each other in external morphology, but W. fujiae is distinguished by having two tetrasporangia per segment rather than one, W. indica by having abundant and persistent trichoblasts, and W. howei by having few and deciduous trichoblasts.     

Ultrastructure and Molecular Phylogeny of Mesodinium coatsi sp. nov., a Benthic Marine Ciliate

Mesodinium is a globally distributed ciliate genus forming frequent and recurrent blooms in diverse marine habitats. Here, we describe a new marine species, Mesodinium coatsi n. sp., originally isolated from interstitial water of surface sand samples collected at Mohang Beach, Korea. The species was maintained under a mixotrophic growth condition for longer than 1 yr by providing a cryptomonad, Chroomonas sp., as the sole prey. Cell morphology and subcellular structure were examined by light microscopy, scanning, and transmission electron microscopy, and molecular phylogeny was inferred from nuclear‐encoded 18S rDNA sequence data. Like other Mesodinium species, M. coatsi consisted of two hemispheres separated by two types of kinetids, and had tentacles located at the oral end of the cell. Several food vacuoles were observed in the cytoplasm, and partially digested prey cells sometimes existed in food vacuoles. Kinetids and the associated accessory structures were quite similar to those previously reported, but M. coatsi was differentiated from other marine Mesodinium species by ultrastructural characters of the dikinetids, polykinetids, and tentacles. We also provided a detailed illustration of infraciliature. Molecular phylogeny revealed that M. coatsi and Mesodinium chamaeleon were closely related to each other.     

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.     

Two new species in the Chaetoceros socialis complex (Bacillariophyta): C. sporotruncatus and C. dichatoensis,and characterization of its relatives,C. radicans and C. cinctus

The diatom genus Chaetoceros is one of the most abundant and diverse phytoplankton in marine and brackish waters worldwide. Within this genus, Chaetoceros socialis has been cited as one of the most common species. However, recent studies from different geographic areas have shown the presence of pseudo‐cryptic diversity within the C. socialis complex. Members of this complex are characterized by curved chains (primary colonies) aggregating into globular clusters, where one of the four setae of each cell curves toward the center of the cluster and the other three orient outwards. New light and electron microscopy observations as well as molecular data on marine planktonic diatoms from the coastal waters off Chile revealed the presence of two new species, Chaetoceros sporotruncatus sp. nov. and C. dichatoensis. sp. nov. belonging to the C. socialis complex. The two new species are similar to other members of the complex (i.e., C. socialis and C. gelidus) in the primary and secondary structure of the colony, the orientation pattern of the setae, and the valve ultrastructure. The only morphological characters that can be used to differentiate the species of this complex are aspects related to resting spore morphology. The two newly described species are closely related to each other and form a sister clade to C. gelidus in molecular phylogenies. We also provide a phylogenetic status along with the morphological characterization of C. radicans and C. cintus, which are genetically related to the C. socialis complex.     

First report of three benthic dinoflagellates,Gambierdiscus pacificus,G. australes and G. caribaeus (Dinophyceae), from Hainan Island,South China Sea

Species of the marine benthic dinoflagellate genus Gambierdiscus are the principal cause of Ciguatera fish poisoning. This genus has been recorded from tropical to temperate oceans, although Gambierdiscus species have rarely been found in Chinese waters. Our work revealed the morphological and genetic characteristics of three potentially toxic Gambierdiscus species observed in the temperate to subtropical waters of China. The fine thecal morphology was determined based on light microscopy and scanning electron microscopy analyses, and these species were also characterized by sequencing the D1–D3 and D8–D10 regions of the LSU rDNA. The morphological and genetic data indicated that these three Gambierdiscus species were G. pacificus, G. australes and G. caribaeus. This work provides the first report of these species in Chinese waters, which increases the known species distribution of this genus.     

Impact of pre‐ and post‐pollination barriers on pollen transfer and reproductive isolation among three sympatric Pedicularis (Orobanchaceae) species

• Pedicularis is the largest genus in the Orobanchaceae (>300) with many species co‐occurring and co‐blooming in subalpine to alpine meadows in the Himalayas. Although it is well known that different Pedicularis species place pollen on different parts of the same bumblebee's body, thus reducing interspecific pollen transfer, it is not known whether post‐pollination components also contribute to reproductive isolation (RI).
• In this study, we quantified the individual strengths and absolute contributions of six pre‐ and post‐pollination components of RI between three sympatric species in two pairs; Pedicularis gruina × Pedicularis tenuisecta (gru × ten) and Pedicularis comptoniifolia × Pedicularis tenuisecta (com × ten).
• All three Pedicularis species shared the same Bombus species. Individual foragers showed a high, but incomplete, floral constancy for each species. Therefore, pre‐pollination barriers were potentially ‘leaky’ as Bombus species showed a low but consistent frequency of interspecific visitation. The RI strength of pre‐pollination was lower in com × ten than in gru × ten. In contrast, post‐pollination barriers completely blocked gene flow between both sets of species pairs. Two post‐pollination recognition sites were identified. Late acting rejection of interspecific pollen tube growth occurred in com♀ × ten♂, while seeds produced in bi‐directional crosses of gru × ten failed to germinate.
• We propose that, although floral isolation based on pollen placement on pollinators in the genus Pedicularis is crucial to avoid interspecific pollen transfer, the importance of this mode of interspecific isolation may be exaggerated. Post‐pollination barriers may play even larger roles for currently established populations of co‐blooming and sympatric species in this huge genus in the Himalayas.

     

Phylogenetic analysis of Dunaliella (Chlorophyta) emphasizing new benthic and supralittoral isolates from Great Salt Lake

Dunaliella, a commercially important chlorophyte, is globally distributed in saline habitats. Morphological species have not been definitively reconciled with phylogenetic analyses. Considerable genetic diversity continues to be discovered in new isolates, especially from soil and benthic habitats. Twenty‐nine new isolates from Great Salt Lake, Utah, many from benthic or supralittoral habitats, were phylogenetically analyzed using ITS1+5.8S+ITS2 in comparison to a broad sampling of available sequences. A few new isolates align in one branch of a bifurcated monophyletic Dunaliella salina clade and several cluster within monophyletic D. viridis. Several others align with relatively few unnamed strains from other locations, comprising a diverse clade that may represent two or more new species. The overall Dunaliella clade is relatively robust, but the nearest outgroups are ambiguously placed with extremely long branches. About half of the isolates, all from benthic or supralittoral habitats, have been persistently sarcinoid in liquid media since isolation. This trait is spread across the Dunaliella phylogeny. The morphology of two sarcinoid strains was documented with light microscopy, revealing an extensive glycocalyx. Clumping behavior of unicellular and sarcinoid strains was unaffected by presence or absence of Mg²⁺ or Ca²⁺, addition of lectin‐inhibiting monosaccharides, or water‐soluble factors from morphologically opposite strains. Results from this investigation have significantly expanded our current understanding of Dunaliella diversity, but it seems likely that much remains to be discovered with additional sampling.     

Identification and Pathogenicity of Lasiodiplodia Species from Eucalyptus urophylla × grandis,Polyscias balfouriana and Bougainvillea spectabilis in Southern China

Species of Lasiodiplodia are important pathogens of a wide variety of plants covering a wide geographical distribution. These fungi can be associated with different symptoms such as stem cankers, shoot blights, fruit rots, dieback and gummosis. Diseases caused by Lasiodiplodia were surveyed on Eucalyptus urophylla × grandis, Polyscias balfouriana and Bougainvillea spectabilis in a nursery in southern China. Based on morphology characteristics and phylogenetic analyses of ITS rDNA sequences and translation elongation factor 1‐alpha (TEF‐1α) gene regions, four species of Lasiodiplodia were identified. Lasiodiplodia theobromae was identified from E. urophylla × grandis, P. balfouriana and B. spectabilis. L. hormozganensis, L. iraniensis and L. pseudotheobromae were identified from B. spectabilis. To our knowledge, with the exception of L. theobromae on E. urophylla × grandis, this study represents the first report of these fungi on the host plants. Pathogenicity tests showed that all Lasiodiplodia spp. obtained in this study are virulent to E. urophylla × grandis and B. spectabilis, and L. theobromae was virulent to P. balfouriana.     

Water velocity regulates macro‐consumer herbivory on the benthic macrophyte Podostemum ceratophyllum Michx.

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