Parietal Chloroplast Research Articles

Phylogeny and ultrastructure of a non-toxigenic dinoflagellate Amphidoma fulgens sp. nov. (Amphidomataceae, Dinophyceae), with a wide distribution across Asian Pacific

Amphidoma languida, a marine thecate dinoflagellate that produces the lipophilic toxin azaspiracids (AZAs), is primarily found in the Atlantic. Although this species has not been recorded in the Asian Pacific, environmental DNAs related to Am. languida have been widely detected in the region by metabarcoding analysis. Their morphology and AZA production remain unclear. In this study, the morphology, ultrastructure, phylogeny, and AZA production of nine Amphidoma strains isolated from Japan, Malaysia, and Philippines were investigated. Phylogenetic trees inferred from rDNAs (SSU, ITS, and LSU rDNA) showed monophyly of the nine Pacific strains and were sister to the Am. languida clade, including the toxigenic strains from the Atlantic. Cells were ellipsoid, 8.7–16.7 µm in length and 7.4–14.0 µm in width, with a conspicuous apical pore complex. A large nucleus in the hyposome, parietal chloroplast with a spherical pyrenoid in the episome, and refractile bodies were observed. Thecal tabulation was typical of Amphidoma, Po, cp, X, 6ʹ, 6ʹʹ, 6C, 5S, 6ʹʹʹ, 2ʹʹʹʹ. A ventral pore was located on the anterior of 1ʹ plate, beside the suture to 6ʹ plate. The presence of a ventral depression, on the anterior of anterior sulcal plate, was different from Am. languida. A large antapical pore, containing approximately 10 small pores, was observed. Cells were apparently smaller than Am. trioculata, a species possessing three pores (ventral pore, ventral depression, and antapical pore). TEM showed the presence of crystalline structures, resembling guanine crystals, and cytoplasmic invaginations into the pyrenoid matrix. Flagellar apparatus lacking the striated root connective is similar to peridinioids and related dinoflagellates. AZAs were not detected from the Pacific strains by LC-MS/MS. This non-toxigenic Amphidoma species, here we propose as Amphidoma fulgens sp. nov., is widely distributed in the Asian Pacific. Moreover, molecular comparison also suggested that most of the environmental DNA sequences previously reported as Am. languida or related sequences from the Asian Pacific were attributable to Am. fulgens.

Myrmecia, Not Asterochloris, Is the Main Photobiont of Cladonia subturgida (Cladoniaceae, Lecanoromycetes).

This study explores the diversity of photobionts associated with the Mediterranean lichen-forming fungus Cladonia subturgida. For this purpose, we sequenced the whole ITS rDNA region by Sanger using a metabarcoding method for ITS2. A total of 41 specimens from Greece, Italy, France, Portugal, and Spain were studied. Additionally, two specimens from Spain were used to generate four cultures. Our molecular studies showed that the genus Myrmecia is the main photobiont of C. subturgida throughout its geographic distribution. This result contrasts with previous studies, which indicated that the main photobiont for most Cladonia species is Asterochloris. The identity of Myrmecia was also confirmed by ultrastructural studies of photobionts within the lichen thalli and cultures. Photobiont cells showed a parietal chloroplast lacking a pyrenoid, which characterizes the species in this genus. Phylogenetic analyses indicate hidden diversity within this genus. The results of amplicon sequencing showed the presence of multiple ASVs in 58.3% of the specimens studied.

Taxonomic Delimitation of the Monostromatic Green Algal Genera Monostroma Thuret 1854 and Gayralia Vinogradova 1969 (Ulotrichales, Chlorophyta)

The genera Monostroma and Gayralia belong to the order of monostromatic green algae; however, their taxonomic delimitation remains controversial at the genus level. This study attempts to address this issue through the combined analysis of the morphology and nuclear-encoded Internal Transcribed Spacer region sequences of monostromatic green algal samples collected in the South China Sea. Our phylogenetic data revealed that the monostromatic specimens were separated into the M. nitidum clade, G. brasiliensis clade, and a single Monostroma sp. clade, and that the inter-genera genetic distance between the Monostroma and Gayralia genera was lower than that observed within the Monostroma genus. All the specimens presented similar morphology in their single cell-layered thallus, with irregularly arranged cells, rounded cell corners, a parietal chloroplast, and predominantly one (>90%) pyrenoid. Their most obvious morphological difference was in thallus thickness and size. Moreover, the monostromatic specimens of the M. nitidum clade corresponded to the morphological description of the M. nitidum-type specimens. The genus Monostroma was erected earlier than the genus Gayralia. Therefore, we propose to assign the genus Gayralia to Monostroma based on the morphological and phylogenetic analysis and genetic distance data presented here.

A phylogenomically informed five-order system for the closest relatives of land plants

The evolution of streptophytes had a profound impact on life on Earth. They brought forth those photosynthetic eukaryotes that today dominate the macroscopic flora: the land plants (Embryophyta).1 There is convincing evidence that the unicellular/filamentous Zygnematophyceae-and not the morphologically more elaborate Coleochaetophyceae or Charophyceae-are the closest algal relatives of land plants.2-6 Despite the species richness (>4,000), wide distribution, and key evolutionary position of the zygnematophytes, their internal phylogeny remains largely unresolved.7,8 There are also putative zygnematophytes with interesting body plan modifications (e.g., filamentous growth) whose phylogenetic affiliations remain unknown. Here, we studied a filamentous green alga (strain MZCH580) from an Austrian peat bog with central or parietal chloroplasts that lack discernible pyrenoids. It represents Mougeotiopsis calospora PALLA, an enigmatic alga that was described more than 120 years ago9 but never subjected to molecular analyses. We generated transcriptomic data of M.calospora strain MZCH580 and conducted comprehensive phylogenomic analyses (326 nuclear loci) for 46 taxonomically diverse zygnematophytes. Strain MZCH580 falls in a deep-branching zygnematophycean clade together with some unicellular species and thus represents a formerly unknown zygnematophycean lineage with filamentous growth. Our well-supported phylogenomic tree lets us propose a new five-order system for the Zygnematophyceae and provides evidence for at least five independent origins of true filamentous growth in the closest algal relatives of land plants. This phylogeny provides a robust and comprehensive framework for performing comparative analyses and inferring the evolution of cellular traits and body plans in the closest relatives of land plants.

Ultrastructure and phylogeny of Parietochloris toyamaensis sp. nov. and P. bilobata (Trebouxiophyceae)

We describe Parietochloris toyamaensis sp. nov. and verify the taxonomic status of P. bilobata (originally described as Neochloris and once combined with Ettlia), using ultrastructural and molecular analyses. P. toyamaensis was isolated from soil collected in Toyama, Japan. It had a parietal chloroplast with pyrenoids that were discontinuously covered with starch segments and penetrated more or less in parallel by thylakoid membranes, and reproduced by forming naked, somewhat dorsoventral, biflagellate zoospores. Two contractile vacuoles were in line lengthwise, located in the median ventral side of the zoospores, as in the type P. alveolaris. The basal apparatus components included a single microtubule in the dexter root. P. toyamaensis was separately resolved from other members of the genus in the 18S rDNA and ITS2 trees. Since the authentic strain ASIB V141 of P. bilobata (stored as Ettlia) has been lost, ASIB V143 was used as a reference in place of it. P. bilobata ASIB V143 was resolved in the ‘Parietochloris sensu stricto’ clade but not ‘Lobosphaera’ clade in the 18S rDNA tree, so taxonomically the combination of N. bilobata with Parietochloris as P. bilobata by Andreyeva was confirmed. In zoospores of the strains of P. bilobata, contractile vacuoles were located in the ventral side, as in P. alveolaris. The taxonomic relationship between P. bilobata and P. grandis, and evaluation of the unique position of contractile vacuoles in dorsoventral zoospores as one of the key characters of Parietochloris were discussed.

Emended description of the genus Eremochloris (Trebouxiophyceae, Chlorophyta), with Eremochloris kamchatica sp. nov. from Kamchatka, Russia

ABSTRACT Three strains of a coccoid green alga were isolated from soil samples collected at the Shiveluch Volcano on the Kamchatka Peninsula. SSU rRNA gene sequence comparisons resolved the strains as members of the genus Eremochloris in the class Trebouxiophyceae. Analyses based on the internal transcribed spacer (ITS) rRNA secondary structure revealed that our isolates were genetically distinct from the type species of this genus. These isolates were characterized by spherical, elliptical or pyriform cells that were solitary with a single excentric nucleus. The cells harboured a single-pyrenoid parietal chloroplast, which was either simple or dissected into clear, curved or undulated lobes. Studies on the life cycle of this alga revealed that asexual reproduction takes place via autospores or biflagellated zoospores. Sexual reproduction is very scarce and is isogamous. All these features suggest a new species, which we name Eremochloris kamchatica. The description of the genus Eremochloris is emended to accommodate the features of the new species.

Chloroidium saccharophilum (Chlorophyta) с побережья озера Байкал (Республика Бурятия, Россия)

The article provides information about green microalga Chloroidium saccharophilum (Trebouxiophyceae) whose history of study dates back to more than 100 years. The issues of its intraspecific variability are considered. We also studied the strain of C. saccharophilum IRK–A 230 isolated from a small puddle on the southeastern shore of Lake Baikal (Republic of Buryatia, Russia). Light and electron microscopy and molecular phylogeny methods establish the species identity of the strain. The alga has an ellipsoidal cell shape, parietal chloroplast and visible pyrenoid with starch sheath; reproduction by equal and unequal autospores in even and odd numbers; the ability to form spherical cells; and accumulated yellow pigments in old non-heterotrophic cultures. The data obtained by us complement the species characteristics, and its biology and geography. The amended description of C. saccharophilum is provided.

New species Micractinium kostikovii (Chlorellaceae, Trebouxiophyceae) from Russia

SUMMARYCorrectly identifying species of Chlorella‐like microalgae is difficult because of their morphological simplicity and high phenotypic plasticity. The use of molecular tools has revolutionized research on algal diversity, enabling such advances as the discovery of numerous new taxa. This article presents the results of a study of strains that are newly isolated from a freshwater Lake Prudovikov (Samara region, Russian Federation). These strains had the typical Chlorella morphology, exhibiting spherical cells and a cup‐shaped parietal chloroplast. The chloroplast contained a single pyrenoid enveloped by starch grains. However, 18S–ITS1–5.8S–ITS2 sequence analyses indicated that the studied strains are strongly allied with the well‐supported genus Micractinium. Based on the results of a comparative analysis of the morphological, molecular and environmental characteristics of the studied strains (employing a polyphasic approach), we propose that they are new species of Micractinium: Micractinium kostikovii sp. nov.

Thorsmoerkia curvula gen. et spec. nov. (Trebouxiophyceae, Chlorophyta), a semi-terrestrial microalga from Iceland exhibits high levels of unsaturated fatty acids

A terrestrial green alga was isolated at Iceland, and the strain (SAG 2627) was described for its morphology and phylogenetic position and tested for biotechnological capabilities. Cells had a distinctly curved, crescent shape with conical poles and a single parietal chloroplast. Phylogenetic analyses of 18S rDNA and rbcL markers placed the strain into the Trebouxiophyceae (Chlorophyta). The alga turned out to belong to an independent lineage without an obvious sister group within the Trebouxiophyceae. Based on morphological and phylogenetic data, the strain was described as a new genus and species, Thorsmoerkia curvula gen. et sp. nov. Biomass was generated in column reactors and subsequently screened for promising metabolites. Growth was optimized by pH-regulated, episodic CO2 supplement during the logarithmic growth-phase, and half of the biomass was thereafter exposed to nitrogen and phosphate depletion. The biomass yield reached up to 53.5 mg L−1 day−1. Fatty acid (FA) production peaked at 24 mg L−1 day−1 and up to 83% of all FAs were unsaturated. At the end of the log phase, approximately 45% of dry mass were lipids, including eicosapentaenoic acid. Carotenoid production reached up to 2.94 mg L−1 day−1 but it was halted during the stress phase. The N-linked glycans of glycoproteins were assessed to reveal chemotaxonomic patterns. The study demonstrated that new microalgae can be found at Iceland, potentially suitable for applied purposes. The advantage of T. curvula is its robustness and that significant amounts of lipids are already accumulated during log phase, making a subsequent stress exposure dispensable.

The red alga Tsunamia transpacifica (Stylonematophyceae) from plastic drift shows adaptation to its uncommon habitat in ultrastructure and soluble low molecular weight carbohydrate composition

The recently described red alga Tsunamia transpacifica (Stylonematophyceae) was previously isolated from plastic drift found at the pacific coast, but the natural habitat remains unknown. Here, we investigate ultrastructural details and the low molecular weight soluble carbohydrate composition to get further insight into the adaptation to this uncommon habitat. By means of high pressure freeze fixation, followed by freeze substitution, we could detect an up to 2-µm-thick cell wall surrounded by a distinct layer of extracellular polymeric substances (EPS), likely responsible for the adhering capacities of Tsunamia. The central position of the nucleus and multilobed parietal chloroplast, already observed by light microscopy, could be confirmed. The ultrastructure revealed large electron-dense bodies (EB) in the central cytoplasm, likely resembling degradation products of the chloroplast. Interestingly, these structures contained phosphorous and cobalt, and iron was found in smaller rounded electron-dense bodies by electron energy loss spectroscopy (EELS). Accumulation of these elements suggests a high biosorption activity of Tsunamia. Liquid chromatography-mass spectrometry (LC–MS) data showed the presence of two heterosides (floridoside and digeneaside) together with the polyol sorbitol, which are known as organic osmolytes and compatible solutes. Taken together, these are the first observations on ultrastructural details, element storage and accumulation of protective compounds are contributing to our understanding of the ultrastructural and osmotic solute basis for the ability of Tsunamia to thrive on plastic surfaces.

Revealing the Characteristics of the Antarctic Snow Alga Chlorominima collina gen. et sp. nov. Through Taxonomy, Physiology, and Transcriptomics.

Snow algae play crucial roles in cold ecosystems, however, many aspects related to their biology, adaptations and especially their diversity are not well known. To improve the identification of snow algae from colored snow, in the present study we used a polyphasic approach to describe a new Antarctic genus, Chlorominima with the species type Chlorominima collina. This new taxon was isolated of colored snow collected from the Collins Glacier (King George Island) in the Maritime Antarctic region. Microscopy revealed biflagellated ellipsoidal cells with a rounded posterior end, a C-shaped parietal chloroplast without a pyrenoid, eyespot, and discrete papillae. Several of these characteristics are typical of the genus Chloromonas, but the new isolate differs from the described species of this genus by the unusual small size of the cells, the presence of several vacuoles, the position of the nucleus and the shape of the chloroplast. Molecular analyzes confirm that the isolated alga does not belong to Chloromonas and therefore forms an independent lineage, which is closely related to other unidentified Antarctic and Arctic strains, forming a polar subclade in the Stephanosphaerinia phylogroup within the Chlamydomonadales. Secondary structure comparisons of the ITS2 rDNA marker support the idea that new strain is a distinct taxon within of Caudivolvoxa. Physiological experiments revealed psychrophilic characteristics, which are typical of true snow algae. This status was confirmed by the partial transcriptome obtained at 2°C, in which various cold-responsive and cryoprotective genes were identified. This study explores the systematics, cold acclimatization strategies and their implications for the Antarctic snow flora.

Taxonomic study of a new green alga, Annulotesta cochlephila gen. et sp. nov. (Kornmanniaceae, Ulvales, Ulvophyceae), growing on the shells of door snails

Some algae are known to grow on shellfish shells. Most of these have been reported in aquatic environments. The species specificity for substrate shells varies, and some algae grow only on the shells of a certain species of shellfish, such as Pseudocladophora conchopheria (Cladophorales, Ulvophyceae) on Lunella coreensis (Trochida, Gastropoda). There are very few reports of algae that grow on land snails. In this study, we discovered green algae growing on the shells of six species of door snails (Clausiliidae) from nine localities in Japan. These green algae formed a green mat composed of thalli embedded in the extracellular matrix. The thallus was composed of aggregated oval cells and peripheral branched filaments. The cells possessed a single parietal chloroplast with a pyrenoid surrounded by two starch sheaths and transversed by a thylakoid. Oil droplets in the cell and ring-like structures on the cell wall surface were frequently observed. The 18S rDNA sequences of all shell-attached algae on different clausiliid species from different localities were almost identical and formed a new clade in the family Kornmanniaceae (Ulvales, Ulvophyceae). No other algae forming visible colonies on the clausiliid shell were found. These findings indicate the presence of specificity between the alga and clausiliid shells. Based on the results of morphological observation and molecular phylogenetic analysis, we propose a new genus and new species of shell-attached green alga, Annulotesta cochlephila.

Photosynthetic fluctuation accompanied by translocation of chloroplasts in Ulva conglobata (Ulvophyceae) grown under a low irradiance regime

SUMMARYFluctuations in photosynthetic characteristics related to chloroplast translocation have been known in the foliose green algae Ulva lactuca var. latissima and var. rigida and U. mutabilis according to photoperiod. In Ulva, the single parietal chloroplast is found along the thallus surface wall and exhibits high photosynthetic activity during the light period; the chloroplast then moves towards the side walls and shows low photosynthetic activity during the dark period. In this study, we re‐investigated whether the photosynthetic ability is dependent on chloroplast location in a unialgal culture of U. conglobata grown and maintained under low irradiance regime by analyzing in vivo absorption spectra, oxygen evolution, and pulse amplitude modulation chlorophyll fluorescence. The light absorbance of the thallus was higher when chloroplast was along the thallus surface wall than when along the side walls and, therefore, the thallus absorbance at 680 nm was used as an index of chloroplast position. Some photosynthetic parameters such as maximum net photosynthetic rate per thallus area and effective quantum yield of photosystem II correlated with the thallus absorbance. The highest rate and absorption were reached 3 to 9 h after the beginning of light period (12 h), which gradually decreased at 10 to 15 h after the beginning of light or dark period. The lowest rate and absorption was observed after the beginning of the dark period. The chloroplast movement was inhibited for 12 h by colchicine, and photosynthetic parameters were found to be dependent on various chloroplast positions in the thallus. Interestingly, the chloroplast moved to the surface and the side walls of the cells under continuous dark and light conditions, respectively, at approximately 48 to 72 h. However, decreased maximum quantum yield was observed under both continuous dark and light conditions.

First Report of Endolithic Members of Rhodosorus marinus (Stylonematales, Rhodophyta) Growing Inside Rhodoliths Offshore Louisiana, Northwestern Gulf of Mexico

Endolithic, red unicells residing in the interior of Lithothamnion rhodoliths, collected offshore the NW Gulf of Mexico in mesophotic rhodolith beds at ~54-55 m depth and maintained in closed microcosms, were used to establish cultures following their isolation. These endolithic unicells subsequently developed into amorphous blobs of palmelloid cell colonies. Each cell contains unstacked, 2-5 lobed parietal chloroplasts, one prominent central pyrenoid, and have a thin or thick cell wall. Single cells, or cell clusters (in pairs, tetrads, or up to 12) are embedded inside an extracellular matrix whose boundaries remain closely appressed to neighboring cell clusters. Cell division by concavo-convex division resulted in hemispherical cells subsequently expanding in size. Plastid tufA, psbA and 16S rDNA sequence analyses confirmed that the colonies are Rhodosorus marinus Geitler. This is the first report of a red alga spending part of its life history endolithically inside biogenic rhodoliths.

First record of the rare freshwater alga Tetrasporopsis fuscescens (Chrysomerophyceae, Ochrophyta) in North America

This study presents the first record of the ochrophyte alga Tetrasporopsis fuscescens in North America, confirmed with light and transmission electron microscopic photomicrographs, cytochemical and molecular phylogenetic analyses. T. fuscescens was recorded rarely, being found in the benthos of only twelve stream sites: nine locations in Southern California and three in Northern California. More than half of the streams were non-perennial, characterized by long dry periods. Tetrasporopsis cells were gold-colored, spherical, with a distinct wall, assembled in the periphery of macroscopical gelatinous colonies, which start as tubular or sac-like structures, but later become membranous. The cells have 1-2 parietal chloroplasts, without a stigma or pyrenoid, and reproduction occurs by longitudinal cell division. Other features of the genus are as follows: cells in the colonies also divide by what appears to be smaller autospores with remnant cell walls remaining, the colonial mucilage consists of cylindrical dichotomously branched tubes radiating from the center of the colony to which attach the peripheral cells, and older cells become filled with large oil droplets. A combined gene tree of sequences from nuclear SSU rDNA, plastid rbcL, psaA, psbA and psbC showed that T. fuscescens specimens from Europe and U. S. A. formed a clade, which clustered with taxa classified in the class Chrysomerophyceae.

Obliquicauda gen. nov. (Trebouxiophyceae, Chlorophyta), including O. inflata sp. nov. and O. apiculata sp. nov.: foliicolous algae from Ficus leaves

ABSTRACTTwo unidentified foliicolous algal strains were isolated from living Ficus leaves in a tropical rainforest of China. Morphological, ultrastructural, and molecular phylogenetic investigations of these strains indicated that they differ from each other but cluster together and represent a new lineage of Trebouxiophyceae in the Choricystis/Botryococcus clade. These strains had similar morphologies with solitary, fusiform, and slightly asymmetrical vegetative cells, a basal stalk, and smooth cell walls. Cells contained a single parietal chloroplast with a pyrenoid surrounded by several starch sheaths and penetrating thylakoids. Asexual reproduction occurred in both strains through the splitting of the mother cell wall into two autospores. Phylogenetic analysis based on 18S, ITS and rbcL showed the two strains as a distinct branch in the Choricystis/Botryococcus clade of the Trebouxiophyceae. Here, we describe the two strains as the new genus, Obliquicauda gen. nov., and two new species, Obliquicauda inflata sp. nov. and Obliquicauda apiculata sp. nov.

Chrysochromulina andersonii sp. nov. (Prymnesiophyceae), a new flagellate haptophyte symbiotic with radiolarians

ABSTRACTThe haptophyte symbiont Chrysochromulina andersonii sp. nov. isolated from the polycystine radiolarian Dictyocoryne truncatum was examined using both natural and cultured materials by light, scanning and transmission electron microscopy as well as molecular phylogenetic analyses of the small subunit (SSU) and large subunit (LSU) rDNA sequences. In culture, the motile cells were saddle-shaped, 3–5 µm long and 3–4 µm wide. They possessed two equal to subequal flagella, a coiling haptonema, and two parietal golden-brown chloroplasts. The scales were arranged in two layers composed of two types: scales with flat rims, 0.19–0.26 µm in diameter, formed the inner layer; whereas, scales with upright rims, 0.25–0.45 µm in diameter, formed the outer layer. Both scales had a faint cross in the centre of the scale face, and the radiating ridges extended from the faint cross to the periphery. Molecular phylogenetic analysis indicated that the SSU and LSU rDNA sequences from our symbiont fell within the clade of Chrysochromulina. However, our symbiont differed in the details of the patterning on the scale face from the other species of Chrysochromulina. Thus, we propose C. andersonii sp. nov. for the symbiotic alga from the polycystine radiolarian D. truncatum.

Chloromonas svalbardensis n. sp. with Insights into the Phylogroup Chloromonadinia (Chlorophyceae).

The traditional green algal genus Chloromonas accommodates mesophilic, cold-tolerant and cold-adapted microorganisms. In this paper, we studied a new strain isolated from a wet hummock meadow in the High Arctic. We used morphological, ultrastructural and molecular data to assess the taxonomic position and phylogenetic relationships of the new isolate. The observed morphological features generally corresponded to the cold-tolerant Chloromonas characteristics. However, ellipsoidal or wide ellipsoidal vegetative cells, a massive parietal cup-shaped chloroplast with a number of continuously connected lobes, a thick cell wall, a prominent hemispherical papilla and the anterior position of an oblong or round eyespot distinguished the alga from all previously described Chloromonas species. Analyses of rbcL and 18S rRNA genes showed that the new strain formed an independent lineage within a clade containing mesophilic and psychrotolerant Chloromonas species. Comparisons of secondary structure models of a highly variable ITS2 rDNA marker supported a separate species identity of the new isolate. Considering the morphological and molecular differences from its relatives, a new psychrotolerant species, Chloromonas svalbardensis, is proposed. Further, our results demonstrated the paraphyletic origin of Chloromonas within Chloromonadinia with genetically, morphologically and ecologically well-defined clades. We discuss a scenario of a possible Chloromonas split and revision.

Coccomyxa antarctica sp. nov. from the Antarctic lichen Usnea aurantiacoatra.

The single celled green alga Coccomyxa antarctica Shunan Cao & Qiming Zhou, sp. nov. was isolated from the Antarctic torrential lichen Usnea aurantiacoatra (Jacq.) Bory. It is described and illustrated based on a comprehensive study of its morphology, ultrastructure, ecology and phylogeny. C. antarctica is a lichenicolous alga which has elongated cells and contains a parietal chloroplast as observed under the microscope. C. antarctica is clearly different from other species by phylogenetic analysis (ITS rDNA and SSU rDNA sequences), also it differs from its phylogenetic closely species C. viridis by its larger cell size.

Ecology, Reproduction, and Classification of the Haptophyte AlgaApistonemaFrom Kansas

Our study of Apistonema pyrenigerum Pascher, a member of the haptophyte algal order Prymnesiales, collected from the Quivira National Wildlife Refuge, Stafford County, Kansas, includes data on its ecology, reproduction, and updated classification. Its habitat was saline and in laboratory cultures its growth indicated its ability to grow in a wide range of salinities, 6–85%. Previous reports for the alga are from Europe: Austria, Britain, Czech Republic, France, and Italy. Each cell possesses two parietal chloroplasts, although sometimes a single one is present. Each chloroplast contains a pyrenoid. The remainder of the cell consists of a large chrysolaminarin (leucosin) droplet and numerous small droplets. Zoospores are triflagellate, suggesting taxonomic placement in the family Prymnesiaceae.