The Extremophile Endolithella mcmurdoensis gen. et sp. nov. (Trebouxiophyceae,Chlorellaceae), A New Chlorella-like Endolithic Alga From Antarctica

The McMurdo Dry Valleys constitute the largest ice-free region of Antarctica and one of the most extreme deserts on Earth. Despite the low temperatures, dry and poor soils and katabatic winds, some microbes are able to take advantage of endolithic microenvironments, inhabiting the pore spaces of soil and constituting photosynthesis-based communities. We isolated a green microalga, Endolithella mcmurdoensis gen. et sp. nov, from an endolithic sandstone sample collected in the McMurdo Dry Valleys (Victoria Land, East Antarctica) during the K020 expedition, in January 2013. The single non-axenic isolate (E. mcmurdoensis LEGE Z-009) exhibits cup-shaped chloroplasts, electron-dense bodies, and polyphosphate granules but our analysis did not reveal any diagnostic morphological characters. On the basis of phylogenetic analysis of the 18S rRNA (SSU) gene, the isolate was found to represent a new genus within the family Chlorellaceae.     

Halocafeteria seosinensis gen. et sp. nov. (Bicosoecida), a halophilic bacterivorous nanoflagellate isolated from a solar saltern

Recently, heterotrophic nanoflagellates (HNF) have been reported to actively ingest prokaryotes in high salinity waters. We report the isolation and culture of an HNF from a Korean saltern pond of 300‰ salinity. The organism is biflagellated with an acronematic anterior flagellum and never glides on surfaces. The mitochondria have tubular cristae. Neither transitional helix nor spiral fiber were observed in the transition zones of the flagella. The cell has a cytostome supported by an arc of eight microtubules, suggesting that our isolate is a bicosoecid. Our isolate had neither mastigonemes, lorica, body scales, nor cytopharynx and thus could not be placed in any of the presently described bicosoecid genera. Phylogenetic analysis of 18S rRNA gene sequences from stramenopiles confirmed the bicosoecid affinities of our isolate, but did not place it within any established genus or family. Its closest relatives include Caecitellus and Cafeteria. The optimal range of growth temperature was 30–35°C. The isolated HNF grew optimally at 150‰ salinity and tolerated up to 363‰ salinity, but it failed to grow below 75‰ salinity, indicating that it could be a borderline extreme halophile. On the basis of its morphological features and position in 18S rRNA trees we propose a novel genus for our isolate; Halocafeteria, n. gen. The species name Halocafeteria seosinensis sp. nov. is proposed.     

Euduboscquella costata n. sp. (Dinoflagellata,Syndinea), an Intracellular Parasite of the Ciliate Schmidingerella arcuata: Morphology,Molecular Phylogeny,Life Cycle,Prevalence, and Infection Intensity

The syndinean dinoflagellate Euduboscquella costata n. sp., an intracellular parasite of the tintinnid ciliate Schmidingerella arcuata, was discovered from Korean coastal water in November of 2013. Euduboscquella costata parasitized in about 62% of the host population, with infection intensity (= number of trophonts in a single host cell) ranging from 1 to 8. Based on morphology and nuclear 18S ribosomal RNA gene sequences, the parasite is new to science. Euduboscquella costata n. sp. had an infection cycle typical of the genus, but had morphological and developmental features that distinguished it from congeneric species. These features include: (1) episome of the trophont with 25–40 grooves converging toward the center of the shield; (2) a narrow, funnel‐shaped lamina pharyngea extending from the margin of the episomal shield to the nucleus; (3) persistence of grooves during extracellular development (sporogenesis); (4) a single food vacuole during sporogenesis; (5) separation of sporocytes early in sporogenesis, regardless of type of spore formed; and (6) dinospore size (ca. 14 μm in length) and shape (bulbous episome with narrower, tapering hyposome). After sporogenesis, E. costata produced four different types of spore that showed completely identical 18S rRNA gene sequences. The gene sequence was completely identical with a previously reported population, Euduboscquella sp. ex S. arcuata, from Assawoman Bay, USA, indicating that the two populations are likely conspecific. Favella ehrenbergii, a widely recorded tintinnid known to host Euduboscquella spp., co‐occurred with S. arcuata, but was not infected by E. costata in field samples or during short‐term, cross‐infection experiments.     

Ultrastructure and taxonomy ofJomonlithus littoralis gen. et sp. nov. (Class prymnesiophyceae), a coccolithophorid from the Northwest Pacific

A new coccolithophorid genusJomonlithus withJ. littoralis as the type species, is described based on specimens isolated from a sand sample collected at the mouth of Nakagawa river, Ibaraki, Japan. This genus is characterized by the coccolith which is composed of an organic base-plate scale and calcified rim elements made up of two different subelements.J. littoralis has been found in several localities along the coast of Japan. Culture and ultrastructure studies gave special attention to the cell cycle, coccolith and scale morphology and the ultrastructure of the cellular organelles. It was confirmed thatJomonlithus is similar toWigwamma Mantonet al., Papposphaera Tangen andPappomonas Manton et Oates on the basis of coccolith morphology and toCricosphaera Braarud andHymenomonas Stein in cellular structure.     

Why one species in New Zealand,Pugetia delicatissima (Kallymeniaceae,Rhodophyta), should become two new genera,Judithia gen. nov. and Wendya gen. nov.

Blade-forming red algae occur worldwide and, prior to DNA sequencing, had been notoriously difficult to identify and classify, especially when lacking critical reproductive features. This, coupled in New Zealand with many longstanding assumptions that taxa were identical to non-New Zealand species or genera, resulted in many misapplied names. Pugetia delicatissima R.E. Norris, an endemic New Zealand blade-forming species of the family Kallymeniaceae, is actually comprised of one existing and one new species belonging to two distinct genera, as established by our phylogenetic analyses of DNA sequences from the rbcL gene. Analyses of combined rbcL and LSU genes showed that neither is closely related to the generitype of Pugetia, the northern-eastern Pacific, P. fragilissima Kylin. We propose the names Judithia and Wendya for these two newly revealed genera. In addition to diagnostic rbcL and LSU sequences, Judithia is morphologically and anatomically characterized by rounded to oblong blades that do not taper basally at the stipe, loosely aggregated surface cortical cells and cystocarps lacking both a pericarp and an ostiole, all features observed in the holotype of P. delicatissima. Wendya, in contrast, is characterized by blades that taper both apically and basally, compactly arranged surface cortical cells and cystocarps that have both a pericarp and a distinct ostiole. The two genera also are distinguished from one other, as well as from Pugetia by features of pre- and post-fertilization development, including the number of subsidiary cells produced on carpogonial and auxiliary branch systems, whether subsidiary cells in the carpogonial branch system fuse with the supporting cell or not, and the site of origin of gonimoblast cells. Although small in area, New Zealand hosts ten of the 27 currently recognized genera in the Kallymeniaceae and is the southern-hemisphere region of greatest generic diversification in this family.     

Lundiella indica gen. et sp. nov., a new member of colonial Volvocales (Chlorophyceae) from India

A new alga designated as Lundiella indica gen. et sp. nov. is described from India. It is at present known only in vegetative condition. It clearly belongs in the colonial Volvocales but its features of vegetative morphology do not agree with those of any known genus of this order.     

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.     

Avrainvillea rotumensis sp. nov. (Bryopsidales, Chlorophyta), a peltate species from the South Pacific

A new species of Avrainvillea was found on the South Pacific island of Rotuma, Fiji. Avrainvillea rotumensis sp. nov. occurs 1.5-3.0 m deep in a high energy current area of the Hoféa Passage, one of the few openings in the fringing reef that surrounds the island. The distinctive peltate growth habit of A. rotumensis is unique for the genus and facilitates quick and accurate field identification. The peltate blade (7–9 cm in diameter at maturity) is unusually thick (34 mm) tapering toward a short (up to 6 cm in length), thick (1.5-2.0 cm in diameter) stipe.     

Molecular phylogeny and taxonomy of the genus Chaetophora (Chlorophyceae,Chlorophyta), including descriptions of Chaetophoropsis aershanensis gen. et sp. nov.

The broadly defined genus Chaetophora consisted of species with minute, uniseriate branching filaments enveloped in soft or firm mucilage forming macroscopic growths that are spherical, hemispherical, and tubercular or arbuscular, growing epiphytically on freshwater aquatic plants and other submerged surfaces in standing or fast‐flowing water. Recent molecular analyses clearly showed that this genus was polyphyletic. In this study, eight strains of Chaetophora and three strains of Stigeoclonium were identified and successfully cultured. In combination with the morphological data, a concatenated data set of four markers (18S + 5.8S + ITS2+ partial 28S rDNA) was also used to determine their taxonomic relationships and phylogenetic positions. The molecular analysis resolved the broadly defined Chaetophora to at least two genera. Species with a globose thallus of genus Chaetophora formed a separate monophyletic clade, which clearly separated from, a type of lobe‐form Chaetophora species. Therefore, we propose to erect a new genus, Chaetophoropsis, which includes all globose species of the Chaetophora. Chaetophoropsis aershanensis was determined to be a new species, based on its special characteristic of profuse long rhizoids. Stigeoclonium polyrhizum, as the closest relative to Chaetophoropsis, revealed its distant relationships to other species of Stigeoclonium. A globose thallus with a thick, soft mucilage matrix, and special rhizoidal branches lent further support to the placement of S. polyrhizum in the genus Chaetophoropsis and had the closest relationship to C. aershanensis. Taxonomic diversity was proven by distinctive morphological differences and by phylogenetic divergence in the broadly defined Chaetophora identified herein.     

New taxa in the Tremellales: Bulleribasidium oberjochense gen. et sp. nov., Papiliotrema bandonii gen. et sp. nov. and Fibulobasidium murrhardtense sp. nov

Two new genera, Bulleribasidium and Papiliotrema, and three new species, B. oberjochense, P. bandonii and Fibulobasidium murrhardtense are described. An integrated analysis of morphological, ultrastructural, physiological, and molecular data indicates that the new taxa belong to the Tremellales (Basidiomycota). Relevant characteristics of the new genera and species are discussed and compared with those of closely related taxa.     

The Morphology,Ultrastructure and SSU rRNA Gene Sequence of a New Freshwater Flagellate,Neobodo borokensis n. sp. (Kinetoplastea,Excavata)

A small free‐living freshwater bacteriotrophic flagellate Neobodo borokensis n. sp. was investigated by electron microscopy and analysis of its SSU ribosomal RNA gene. This protist has paraxonemal rods of typical bodonid structure in the flagella, mastigonemes on the proximal part of the posterior flagellum, two nearly parallel basal bodies, a compact kinetoplast, and discoid mitochondrial cristae. The flagellar pocket is supported by three microtubular roots (R1, R2 and R3) originating from the kinetosome. The cytopharynx is supported by the root R2, a microtubular prism, cytopharynx associated additional microtubules (CMT) and cytostome associated microtubules (FAS) bands. Symbiotic bacteria and small glycosomes were found in the cytoplasm. Cysts have not been found. The flagellate prefers freshwater habitats, but tolerates salinity up to 3–4‰. The overall morphological and ultrastructural features confirm that N. borokensis represents a new species of the genus Neobodo. Phylogenetic analysis of SSU rRNA genes is congruent with the ultrastructure and strongly supports the close relationship of N. borokensis to Neobodo saliens, N. designis, Actuariola, and a misidentified sequence of “Bodo curvifilus” within the class Kinetoplastea.