Pinguiococcus pyrenoidosus gen. et sp. nov. (Pinguiophyceae), a new marine coccoid alga

A coccoid marine alga, collected from an aquaculture tank and maintained in culture as CCMP1144, was examined using light and electron microscopy. Young, rapidly growing cells were mostly spherical in shape, approximately 4–6 μm in diameter. Older cells often produced protrusions and pseudopodia‐like extensions, giving cells an amoeboid‐like appearance, but no amoeboid movement was observed and the pseudopodia‐like extensions exhibited no active movement. The single chloroplast had a typical photosynthetic stramenopile ultrastructure. A large stalked pyrenoid was easily observed by light microscopy. Ultrastructurally, the granular portion of the pyrenoid was divided into sections by a penetrating chloroplast envelope. A mitochondrion was often, but not always, adjacent to the pyrenoid, and in some cases the mitochondrion formed a ‘cap’ over the protruding pyrenoid. The Golgi cisternae were (when viewed in cross‐section) curved toward the nucleus. A peripheral network of anastomosing tube‐like membranes was located immediately beneath the plasmalemma. Two centrioles were located adjacent to the nuclear envelope. Lipid‐like and electron transparent vacuoles were present. Based on this investigation and data published elsewhere (large percentage of eicosapentaenoic acid, 18S rRNA and rbcL genes), this alga was described as Pinguiococcus pyrenoidosus gen. et sp. nov.     

Pinguiochrysis pyriformis gen. et sp. nov. (Pinguiophyceae), a new picoplanktonic alga isolated from the Pacific Ocean

Pinguiochrysis pyriformis gen. et sp. nov. is a brown, naked, non‐motile, marine picoplankton. A culture was established from a surface sample collected in 1991 from the tropical Western Pacific Ocean. Typical cells of P. pyriformis are distinctively pear‐shaped and have one ovoid chloroplast; these two features distinguish this species from the other picophytoplankton species. However, the pyriform morphology is not consistent and cells frequently change to a subspherical shape. The chloroplast and mitochondrion ultrastructure confirm that this species belongs to the photosynthetic stramenopiles (chromophytes). Additional distinctive ultrastructural characteristics of P. pyriformis include (i) a chloroplast envelope forming a tubular invagination that penetrates into the pyrenoid; (ii) thylakoid lamellae consisting of more than three layers in some cells; (iii) the lack of basal bodies and centrioles; and (iv) the lack of scales or other extracellular structures. Based on the morphological features, this picoplanktonic species was described as a new species and placed in the Pinguiophyceae on the basis of the molecular phylogenetic analysis and biochemical data published elsewhere.     

Ultrastructure and taxonomy of a marine photosynthetic stramenopile Phaeomonas parva gen. et sp. nov. (Pinguiophyceae) with emphasis on the flagellar apparatus architecture

Phaeomonas parva gen. et sp. nov., a marine photosynthetic stramenopile from oceanic water near the Caroline Islands, is described. Cells are naked and spherical to ovoid. The alga is motile with two laterally inserted flagella during the light period, whereas during the dark period, it absorbs the flagella and rounds up. The anterior (immature, No. 2) long flagellum possesses tubular tripartite mastigonemes. The posterior (mature, No. 1) short flagellum is smooth and has autofluorescence at the base. The cupshaped, yellowish‐brown chloroplast occupies the posterior half of the cell, and a pyrenoid occurs in the inner cavity of the cup‐shaped chloroplast. The flagellar apparatus has several unusual features. Two basal plates and a two‐gyred proximal helix in the flagellar transitional region may suggest that P. parva is related to the Pelagophyceae, Dictyochophyceae and Sulcochrysis biplastida, a photosynthetic stramenopile of uncertain taxonomic position. The R3 and R4 roots form a loop that resembles phagotrophic chrysophytes. However, this resemblance is superficial because Phaeomonas is not phagotrophic, its R3 root has a different number of microtubules and its R3 root does not split to form a food‐uptake mouth. Phaeomonas has a ‘bypassing root’, which is found only with the Phaeophyceae, Giraudyopsis stellifera (Chrysomerophyceae), and Ankylochrysis lutea (probably a member of the Pelagophyceae). The taxonomic position of P. parva could not be determined solely from ultrastructural features. However, molecular phylogeny and biochemical analyses (published separately) strongly supported a relationship between P. parva and four other monotypic strameno‐piles, Glossomastix, Pinguiochrysis, Pinguiococcus and Polypodochrysis. Although these algae are morphologically distinct, they have unusually high percentages of polyunsaturated fatty acids, especially eicosapentoic acid. This unusual assemblage of stramenopiles is classified in a new class, the Pinguiophyceae (published separately), and P. parva is its only biflagellate member.     

Sauertylenchus labiodiscus n. gen., n. sp., from Australia (Nematoda:Tylenchorhynchinae)

Sauertylenchus labiodiscus n. gem, n. sp. is described and illustrated from soil around Rhagodia sp. in Australia. It can be distinguished from the most closely related genus Tylenchorhynchus Cobb, 1913 by the distinctly set-off, rounded, lip region with a conspicuous labial disc, and long thin stylet. The face view and spicules of Sauertylenchus labiodiscus are illustrated with scanning electron micrographs. The subfamilies Tylenchorhynchinae and Merlininae ale discussed.     

Aurearenophyceae classis nova, a new class of Heterokontophyta based on a new marine unicellular alga Aurearena cruciata gen. et sp. nov. inhabiting sandy beaches

A new heterokontophyte alga, Aurearena cruciata gen. et sp. nov., was isolated from sandy beaches in Japan. Isolates were characterized by light and electron microscopy, spectroscopy of pigment composition, and molecular phylogenetic analyses using 18S rDNA and rbcL. The alga usually possessed a cell wall but also retained two heterokont flagella beneath the cell wall. Each walled cell first produced only a single flagellate cell that subsequently divided into two flagellate cells. Electron-opaque vesicles, possibly associated with cell wall formation, were observed beneath the cell membrane. The chloroplast consisted of two compartments, each enclosed by a chloroplast envelope and the inner membrane of the chloroplast endoplasmic reticulum; these two compartments were surrounded by a common outer membrane of chloroplast endoplasmic reticulum. Molecular phylogenetic trees suggested that this alga was a new and independent member of the clade that included the Phaeophyceae and Xanthophyceae (PX clade). A new class, Aurearenophyceae classis nova was proposed for A. cruciata.     

Shimiella gen. nov. and Shimiella gracilenta sp. nov. (Dinophyceae,Kareniaceae), a Kleptoplastidic Dinoflagellate from Korean Waters and its Survival under Starvation

A small dinoflagellate, ~13 μm in cell length, was isolated from Jinhae Bay, Korea. Light microscopy showed that it was similar to the kleptoplastidic dinoflagellate Gymnodinium gracilentum nom. inval. rDNA sequences were obtained and its anatomy and morphology described using light and scanning and transmission electron microscopy. Phylogenetic analyses indicated that it belonged to the family Kareniaceae. However, its large subunit (LSU) rDNA sequences were 5.2–9.5% different from those of the other five genera in the family, and its clade was clearly divergent from that of each genus. Its overall morphology was different from those of the other five genera in the family and from Gymnodinium. Unlike Gymnodinium, this dinoflagellate did not have a horseshoe‐shaped apical groove, nuclear envelope chambers, or a nuclear fibrous connective (NFC). It had an apical line of narrow amphiesmal vesicles and an elongated apical furrow crossing the apex. Cells were covered with polygonal amphiesmal vesicles arranged in 16 rows. Starved cells did not contain their own plastids, eyespots, pyrenoids, peridinin, or fucoxanthin. However, they could survive without added prey for approximately one month using chloroplasts from the cryptophyte prey Teleaulax amphioxeia, indicating kleptoplastidy. Because this taxon is genetically distinct at the generic rank from the other genera in Kareniaceae, it is placed in Shimiella gen. nov., and because G. gracilentum was invalid, the new bionomial S. gracilenta sp. nov. is proposed.     

Chromonema heliothidis n. gen., n. sp. (Steinernematidae,Nematoda), a Parasite of Heliothis zea (Noctuidae,Lepidoptera), and Other Insects

Chromonema heliothidis n. gen., n. sp. is described as an entomophilic nematode of Heliothis zea and other lepidopterous larvae; the diagnosis of the family Steinernermatidae is emended. In most morphological and host-parasite features, this nematode is similar to neoaplectanid nematodes; however, males are different in having a peloderan bursa and straight to slightly curved spicules. Although the infective-stage juveniles only give rise to hermaphrodites, the nematode is heterogonic, with both males and females being produced in the second generation. Parasitized hosts are brick-red in color and luminescent in the dark because of the association of a chromogenic, bioluminescent bacterium with the nematode. The nematode is capable of parasitizing a wide range of insects with lepidopterous larvae being most susceptible.     

Malawimonas jakobiformis n. gen., n. sp. (Malawimonadidae n. fam.): A Jakoba-like Heterotrophic Nanoflagellate with Discoidal Mitochondrial Cristae

Malawimonas jakobiformis n. gen., n. sp., is established for a bacterivorous heterotrophic nanoflagellate isolated from the Malawi shore of Lake Nyasa (eastern Africa). Trophic stages observed were anteriorly biflagellate and naked. The posterior flagellum of a trophic cell resided in a conspicuous groove on the ventral surface, and bore a prominent vane. A Golgi stack and a mitochondrion with discoidal cristae were present anterior to the nucleus. The kinetid consisted of two short, slightly separated basal bodies, four microtubular roots, and associated fibers and bands. The three microtubular roots associated with the posterior basal body were associated with the ventral groove, while the single root associated with the anterior basal body gave rise to secondary cytoskeletal microtubules. Dividing cells became rounded, with persistent flagella. Cysts were uninucleate, and had thin organic walls without clearly differentiated apertures or ornamentation but with conspicuous attachment pads. Kinetid elements were present within cysts. On the basis of microscopical features, especially those of the kinetid, the nearest relatives of M. jakobiformis are the mitochondriate “jakobid” protists (families Histionidae and Jakobidae) and the amitochondriate retortamonads. Malawimonadidae n. fam. is established to accommodate this species.     

Saetheriella amplicristata gen. n., sp. n., a new Orthocladiinae (Diptera: Chironomidae) from Tennessee

The generic diagnosis of the male imago of a new genus of the subfamily Orthocladiinae (Chironomidae), Saetheriella is given. The genus is characterized by protruding, hairy eyes; antenna with straight, apical seta; antepronotum reduced; squama without setae; Cu₁ distinctly downcurved; and anal point short, triangular, covered with microtrichia and with two strong, lateral setae. The genus is close to Gynnidocladius Sublette & Wirth, Unniella Sæther and Parakiefferiella Thienemann. The distribution of the genera shows evidence of a Gondwanian connection. The male imago of the only included species S. amplicristata sp. n. is described.     

Ultrastructure and 18S rDNA sequence analysis of Wobblia lunata gen. et sp. nov., a new heterotrophic flagellate (Stramenopiles, Incertae sedis)

A new heterotrophic flagellate Wobblia lunata gen. et sp. nov. is described. This organism usually attaches to the substratum showing a wobbling motion, and sometimes glides on the substratum or swims freely in the medium. W. lunata has various features characteristic of the stramenopiles. These include a hairy flagellum with tripartite tubular hairs, a mitochondrion with tubular cristae, arrangement of flagellar apparatus components and a double helix in the flagellar transition zone. W. lunata shares a double helix with heterotrophic stramenopiles, including Developayella elegans, oomycetes, hyphochytrids, opalinids and proteromonads, and could be placed in the phylum Bigyra Cavalier-Smith. However, from 18S rDNA tree analysis, these organisms form two distantly-related clades in the stramenopiles, and Wobblia appears at the base of the stramenopiles. Evaluation of morphological features and comparison of 18S rDNA sequences indicate that W. lunata is a member of the stramenopiles, but it is distinct from any other stramenopiles so far described. Its phylogenetic position within the stramenopiles is uncertain and therefore W. lunata is described as a stramenopile incertae sedis.     

Pseudonotohymena antarctica n. g., n. sp. (Ciliophora,Hypotricha), a New Species from Antarctic Soil

A new soil ciliate, Pseudonotohymena antarctica n. g., n. sp., from King George Island, Antarctica, is described based on live observation, protargol impregnation, and its 18S rRNA gene. The new genus Pseudonotohymena is morphologically similar to the genus Notohymena Blatterer and Foissner 1988 in the following characteristics: 18 fronto‐ventral‐transverse cirri, a flexible body, undulating membranes, dorsomarginal kineties, and the number of cirri in the marginal rows. However, Pseudonotohymena differs from Notohymena particularly in the dorsal ciliature, that is, in possessing a nonfragmented dorsal kinety (vs. fragmented). In addition, the molecular phylogenetic relationship of the new species differs from that of Notohymena species. On the basis of the morphological features, the genetic data, and morphogenesis, we establish P. antarctica n. g., n. sp. In addition, the cyst morphology of this species is described.     

Thiomicrospira pelophila,gen. n., sp. n., a new obligately chemolithotrophic colourless sulfur bacterium

From marine mud flats a very thin, comma- or spiral-shaped bacterium was isolated. The new organism was an obligately chemolithotrophic sulfur bacterium. Its physiology was found to be essentially similar to that ofThiobacillus thioparus. Because of the spirillum-like appearance it was proposed to classify this bacterium into a new genusThiomicrospira, with the species nameTms. pelophila. Tms. pelophila and a marineT. thioparus, which was isolated from the same mud, occupy different niches in this habitat.Tms. pelophila has a remarkable sulfide-tolerance as compared withT. thioparus. This property could be used for the specific enrichment ofTms. pelophila. The organism was also readily isolated in pure culture by filtering mud suspensions through a 0.22 Μm membrane filter.     

Praealbonemertes whangateaunienses n. gen. and n. sp., a new heteronemertean from New Zealand

Abstract

A new genus and species of heteronemertean, Praealbonemertes whangateaunienses n. gen. and n. sp., is described and illustrated. The species is characterised by inter alia a cephalic lacuna with strands of longitudinal muscle fibres, a proboscis with three muscle layers, and a well-developed muscle plate dorsal to the foregut and anterior intestine. The material was collected in New Zealand.     

Monopylocystis visvesvarai n. gen., n. sp. and Sawyeria marylandensis n. gen., n. sp.: two new amitochondrial heterolobosean amoebae from anoxic environments

Two new species of heterolobosean amoebae from anoxic environments, Monopylocystis visvesvarai and Sawyeria marylandensis, are described on the basis of light microscopy, electron microscopy, and their phylogenetic affiliation based on analyses of nuclear small-subunit ribosomal RNA gene sequences. Both species lack mitochondria but have organelles provisionally interpreted as hydrogenosomes, and neither can tolerate aerobic conditions. As their conditions of culture do not exclude all oxygen, they may be microaerophiles rather than strict anaerobes. Both species have unusual nucleolar morphologies. Monopylocystis visvesvarai, from a marine sediment, has nucleolar material distributed around the nuclear periphery. It is the first non-aerobic heterolobosean protist for which a cyst is known; the cyst is unmineralized and unornamented except for a single, raised, plugged pore. Sawyeria marylandensis, from an iron-rich freshwater stream, has nucleolar material distributed in one or two parietal masses, which persist during mitosis. In phylogenetic analyses of small-subunit rRNA gene sequences, Monopylocystis visvesvarai, Sawyeria marylandensis and Psalteriomonas lanterna converge to form a single clade of non-aerobic (anaerobic/microaerophilic) heteroloboseans.     

A new class of the stramenopiles,Placididea Classis nova: description of Placidia cafeteriopsis gen. et sp. nov

A marine flagellate resembling Cafeteria roenbergensis (bicosoecids, stramenopiles) in cell shape and behavior of the cell while attached to substratum was collected from the coast of Japan. The flagellate was examined by light and electron microscopy, and the 18S rDNA was sequenced to elucidate its taxonomic and phylogenetic position. Ultrastructural features suggested that the flagellate is not a bicosoecid, but a relative of the recently described stramenopile, Wobblia lunata. 18S rDNA phylogenetic trees also revealed that the flagellate forms a monophyletic clade with W. lunata and that it is distantly related to Cafeteria and other bicosoecids. The flagellate differs from W. lunata due to its lack of wobbling motion as well as intracellular features such as the number of mitochondria, flagellar apparatus architecture, the presence of a paranuclear body and cytoplasmic microtubules. The similarity of 18S rDNA sequences was 81% between the flagellate and W. lunata. This new flagellate was described as Placidia cafeteriopsis gen. et sp. nov. Because the phylogenetic lineage comprised of W. lunata and P. cafeteriopsis was one of the major, deep-branching clades of the stramenopiles, the class Placididea (= Placidiophyceae) classis nova was proposed.     

Neosychnocotyle maggiae, n. gen., n. sp. (Platyhelminthes: Aspidogastrea) from freshwater turtles in northern Australia

Neosychnocotyle maggiae, n. gen., n. sp., (Aspidogastrea) is described from the pig-nosed turtle, Carettochelys insculpta, and reported from the Victoria River red-faced turtle, Emydura victoriae, all from the Daly River, Northern Territory, Australia. Neosychnocotyle n. gen. is differentiated from all aspidogastrean genera but one by the absence of a cirrus sac. The similar Sychnocotyle also lacks a cirrus sac, but Neosychnocotyle n. gen. differs from the former genus by possessing a narrow, tapered anterior end, a ventral disk that covers the posterior end of the body, a genital pore that is displaced anteriorly, and a vas deferens that is less convoluted and less robust. Analysis of ribosomal DNA sequences demonstrates substantial sequence variability between representatives of Sychnocotyle and Neosychnocotyle maggiae, n. gen., n. sp. It is possible that this new parasite may reach sexual maturity only in C. insculpta. This is only the second aspidogastrean species reported from Australian freshwater turtles.