Similar Genera Research Articles

Microbiological processes of the carbon and sulfur cycle in cold methane seeps in the North Atlantic

Functioning of microbial communities in surface sediments of the Haakon Mosby underwater mud volcano (lat. 72 degrees N) and in gas seepage fields of the Vestnesa Ridge was investigated using Mir-1 and Mir-2 deep-sea submersibles during the 40th expedition of the research vessel Academician Mstislav Keldysh. Large areas of sedimentary deposits of the Haakon Mosby mud volcano (HMMV) and pockmarks of the Vestnesa Ridge (VR) are covered with bacterial mats 0.1 to 0.5 cm thick. The microbial community making up bacterial mats of the HMMV was predominated by large filamentous bacteria with filaments measuring up to 100 microns in length and 2 to 8 microns in width. The occurrence of rosettes allowed the observed filamentous bacteria to be referred to the morphologically similar genera Leucothrix or Thiothrix. Three morphological types of filamentous bacteria were identified in bacterial mats covering VR pockmarks. Filaments of type one are morphologically similar with representatives of the genera Thioploca or Desmanthos. Type two filaments had numerous inclusions of sulfur and resembled representatives of the genus Thiothrix. The third morphological type was constituted by single filaments made up of tightly connected disk-like cells and can, apparently, be assigned to the genus Beggiatoa. The rates of methane oxidation (up to 1570 microliters C/(dm3 day)) and sulfate reduction (up to 17 mg S/(dm3 day)) measured in surface sediments of HMMV and VR were close to the maximum rates of these processes observed in badly polluted regions of the northwestern shelf of the Black Sea. High rates of microbiological processes correlated with the high number of bacteria. The rate of methane production in sediments studied was notably lower and ranged from 0.1 to 3.5 microliters CH4/(dm3 day). Large areas of the HMMV caldera were populated by pogonophoras, represented by the two species, Sclerolinum sp. and Oligobrachia sp. The mass development of Sclerolinum sp. in the HMMV caldera was by the activity of aerobic methane-oxidizing bacteria localized inside the cells of these animals. Bacterial cells were also found in the trophosome tissue of Oligobrachia sp., but in cells of these bacteria, we did not observe the membrane structures typical of methanotrophs. The localization pattern of pogonophoras on the surface of reduced sediments suggests that the predominant bacteria in Oligobrachia tissues are sulfur-oxidizing endosymbionts.

Phylogenetic Relationships of Chaetomium and Similar Genera Based on Ribosomal DNA Sequences

Phylogenetic Relationships of Chaetomium and Similar Genera Based on Ribosomal DNA Sequences

Phylogenetic relationships of Chaetomium and similar genera based on ribosomal DNA sequences

The 30 taxa sampled for this study were chosen based on their taxonomic position or particular morphological characters, which are related to those of Chaetomium. The 15 fungal isolates sequenced herein were obtained during a fungal biodiversity survey of tropical soils or from the collections of R.T. Hanlin. Fifteen species were selected from the published data. The aligned sequences of the 5’ portion of the 18S ribosomal DNA were analyzed to infer the phylogenetic relationships among Chaetomium and related genera. The sequence data confirmed the generic entity of Achaetomium and placed Ascotricha within the Xylariaceae. The analyses also defined the monophyletic lineage of the Microascaceae and the evolutionary linkages between the families Sordariaceae and Chaetomiaceae. The placement of Coniochaeta in the Coniochaetaceae and Chaetomium and Achaetomium in the Chaetomiaceae, under the order Sordariales, is supported by this study.

Generic Placement of Species Excluded from Arabidopsis (Brassicaceae)

Generic Placement of Species Excluded from Arabidopsis (Brassicaceae)

Review of Raxa (Hemiptera: Pyrrhocoridae)

The genus and the type species Raxa collaris Distant are redescribed. A new species R. nishidai and its 2nd and 4th instars are described. Raxa is compared with 4 similar genera, Melamphaus Stal , Probergrothius Kirkaldy , Roscius Stal, and Antilochus Stal; Raxa appears to be most closely related to the last. R. collaris occurs in Vietnam and Laos, and R. nishidai has been collected only from Indonesia. R. nishidai is predacious, particularly upon the pyrrhocorid Melamphaus faber (F.); it is not known if R. collaris is also predacious. Predation in the Pyrrhocoridae is discussed briefly.

RUDOLOCULINA HOOPERI, A NEW MILIOLID WITH AN AGGLUTINATED OUTER SURFACE FROM THE NORTHEASTERN PACIFIC OCEAN

Rudoloculina hooperi , a new miliolid from Holocene and modern shelf sediments of the northeastern Pacific Ocean, is characterized by chambers that are quadrate in cross-section and by a test wall with embedded agglutinated grains, some of which consist of miliolid-type shell material (subparallel calcite laths). The agglutinated grains are either calcareous and low in magnesium (Mg/Ca ≤ 0.01) or silicic. Rudoloculina hooperi has previously been mistakenly reported from the same region as Quinqueloculina agglutinata Cushman. The morphologically similar genus Cycloforina has been reported mostly from warmer waters, suggesting that R . hooperi is near the northern limit of its range in the Gulf of Alaska.

Genus statistics of the Virgo N-body simulations and the 1.2-Jy redshift survey

We study the topology of the Virgo N-body simulations and compare it with the 1.2-Jy redshift survey of IRAS galaxies by means of the genus statistic. Four high-resolution simulations of variants of the CDM cosmology are considered: a flat standard model (SCDM), a variant of it with higher large-scale power (τCDM), and two low-density universes, one open (OCDM, Ω0 = 0.3) and one flat (ΛCDM, Ω0 = 0.3, Λ 0.7). In all cases, the initial fluctuation amplitudes are chosen so that the simulations approximately reproduce the observed abundance of rich clusters of galaxies at the present day. The fully sampled N-body simulations are examined down to strongly non-linear scales, both with spatially fixed smoothing and with an adaptive smoothing technique. While the τCDM, ΛCDM and OCDM simulations have very similar genus statistics in the regime accessible to fixed smoothing, they can be separated with adaptive smoothing at small mass scales. In order to compare the N-body models with the 1.2-Jy survey, we extract large ensembles of mock catalogues from the simulations. These mock surveys are used to test for various systematic effects in the genus analysis and to establish the distribution of errors of the genus curve. We find that a simple multivariate analysis of the genus measurements is compromised both by non-Gaussian distributed errors and by noise that dominates the covariance matrix. We therefore introduce a principal components analysis of the genus curve. With a likelihood ratio test we find that the 1.2-Jy data favour the ΛCDM, τCDM and OCDM models compared with SCDM. When genus measurements for different smoothing scales are combined, the SCDM model can be excluded at a 99 per cent confidence level, while the other three models fit the 1.2-Jy data well. These results are unlikely to be significantly modified if galaxies are biased tracers of the mass, provided that biasing preserves a monotonic relation between galaxy density and mass density.

Some Chemotaxonomic and Physiological Properties of the Genus Sphaerotilus

Ten reference strains of the genus Sphaerotilus and five isolates of filamentous bacteria obtained from activated sludge and morphologically assigned to the genus Sphaerotilus were studied for cellular fatty acid composition, quinone type, physiological characteristics and protein profiles. All strains had the Q-8 ubiquinone as the major quinone. The main components of cellular fatty acids in all strains were the straight chain unsaturated acid 16:1 and saturated acid 16:0. All strains contained the hydroxylated fatty acid 3-OH 10:0, sometimes only in minor amounts or traces. Analysis of physiological properties showed phenotypic homogeneity among the tested organisms. From 240 tested organic compounds, several sugars, organic acids and aromatic compounds could be utilized as sole carbon source. A clear differentiation from strains belonging to the morphological similar genus Leptothrix was possible with several carbon source utilization tests. Standardized protein profiles of the isolates were also very similar indicating a high degree of homogeneity. The results of the chemotaxonomic characterization are in line with the phylogenetic allocation of the genus Sphaerotilus within the Rubrivivax subdivison of the β subclass of the Proteobacteria .

Aquaphila albicans gen. et sp. nov., a hyphomycete from submerged wood in the tropics

Aquaphila albicans gen. and sp. nov. from submerged wood in the tropics is described and illustrated. It produces hyaline, multiseptate, fusoid or falcate conidia resembling the macroconidia of Fusarium species, but differs by its conidiogenesis and the aquatic habitat. The conidiophores of A. albicans are septate, hyaline, sympodially proliferating with conidiogenous denticles. Conidial development in A. albicans has been studied in culture and results are presented. The genus is compared with similar genera.

Enridescalsia, a new genus of conidial fungi from submerged leaves in Cuba

Enridescalsia gen. nov., characterized by synchronous, polytretic conidiogenous cells and brown euseptate conidia, is described and illustrated from submerged, decaying leaves of Terminalia cattapa from Cuba. Notes on similar genera are given.

Arthrowallemia, a new genus of hyphomycetes from tropical litter

Arthrowallemia anam. gen. nov., characterized by holothallic conidiogenesis, secession randomly schizolytic, and cylindrical, septate, brown conidia emerging from conspicuous unbranched conidiophores, is described and illustrated. The type species, A. formosa sp. nov., was collected on unidentified decaying leaves in Cuba. Notes on similar genera are given.

Sirelina orduensis (Foraminifera) a New Genus and Species from the Maastrichtian of Northeast Anatolia (Gölköy-Ordu)

Sirelina orduensis (Foraminifera) a New Genus and Species from the Maastrichtian of Northeast Anatolia (Gölköy-Ordu)

Aleurodicus pulvinatus (Maskell) (Homoptera: Aleyrodidae), and its emergence as a pest of coconut in the Caribbean

Aleurodicus pulvinatus (Maskell) has recently emerged as a serious pest of coconut in St. Kitts and Nevis, Leeward Islands. Its recognition, synonymy with A. iridescens Cockerell and relationship to another pest species, A. cocois (Curtis), are discussed. An identification key is provided for Caribbean species of Aleurodicus (including the important pest, A. dispersus Russell) and the morphologically similar genus, Lecanoideus.

Pseudoclathrosphaerina evamariae gen. et sp. nov. and Sympodioclathra globosa gen. et sp. nov., two aeroaquatic fungi similar to Clathrosphaerina

Pseudoclathrosphaerina evamariae and Sympodioclathra globosa are described and illustrated as new genera and species, respectively. Their features are outlined and compared to similar genera, especially to Clathrosphaerina. The ecological niche as members of the aeroaquatic fungi is discussed and their distribution recorded.

Genus statistics of the Virgo N-body simulations and the 1.2-Jy redshift survey

We study the topology of the Virgo N-body simulations and compare it with the 1.2-Jy redshift survey of IRAS galaxies by means of the genus statistic. Four high-resolution simulations of variants of the CDM cosmology are considered: a flat standard model (SCDM), a variant of it with higher large-scale power (τCDM), and two low-density universes, one open (OCDM, Ω0 = 0.3) and one flat (ΛCDM, Ω0 = 0.3, Λ 0.7). In all cases, the initial fluctuation amplitudes are chosen so that the simulations approximately reproduce the observed abundance of rich clusters of galaxies at the present day. The fully sampled N-body simulations are examined down to strongly non-linear scales, both with spatially fixed smoothing and with an adaptive smoothing technique. While the τCDM, ΛCDM and OCDM simulations have very similar genus statistics in the regime accessible to fixed smoothing, they can be separated with adaptive smoothing at small mass scales. In order to compare the N-body models with the 1.2-Jy survey, we extract large ensembles of mock catalogues from the simulations. These mock surveys are used to test for various systematic effects in the genus analysis and to establish the distribution of errors of the genus curve. We find that a simple multivariate analysis of the genus measurements is compromised both by non-Gaussian distributed errors and by noise that dominates the covariance matrix. We therefore introduce a principal components analysis of the genus curve. With a likelihood ratio test we find that the 1.2-Jy data favour the ΛCDM, τCDM and OCDM models compared with SCDM. When genus measurements for different smoothing scales are combined, the SCDM model can be excluded at a 99 per cent confidence level, while the other three models fit the 1.2-Jy data well. These results are unlikely to be significantly modified if galaxies are biased tracers of the mass, provided that biasing preserves a monotonic relation between galaxy density and mass density.

Lecanostictopsis gen. nov., and related leaf-spotting fungi on Syzygium species

The new generic name Lecanostictopsis is introduced with three species, L. kamatii (type species), L. syzygii and L. noumeaensis sp. nov., all of which are associated with leaf lesions on species of Syzygium. The genus is compared and contrasted with Lecanosticta, Stigmina and similar genera. The position of Cercostigmina is discussed in relation to Pseudocercospora and Cercoseptoria. Cercostigmina syzygii sp. nov. associated with leaf lesions on S. cordatum is described, and compared and contrasted with Stenella marasasii on the same host substratum. Pseudocercospora syzygiicola sp. nov. is described from leaf lesions on S. cordatum fom South Africa, while Pseudocercospora syzygiorum sp. nov. from S. cumini and Passalora syzygii from S. cumini and S. jambos are described from India.

Molecular phylogeny and biogeography of the Tasmanian and New Zealand mudfishes (Salmoniformes : Galaxiidae)

The phylogenetic affinities of the diadromous Tasmanian mudfish, Galaxias cleaveri, have long been problematic. Some systematists have suggested that this species is closely related to the morphologically similar but non-diadromous New Zealand mudfish genus, Neochanna, while others argued that the similarities represent convergent evolution. Most recently, the Tasmanian mudfish was allocated to Neochanna on morphological grounds. The current paper presents sequence data from two mitochondrial genes that support this decision, revealing a close phylogenetic relationship between Tasmanian and New Zealand mudfish. Molecular clock calibrations are used to examine hypotheses of mudfish evolution and biogeography. Estimated divergence times are consistent with the suggestion that Neochanna burrowsius and N. apoda were separated by the uplift of New Zealand’s southern Alps about five million years ago. In addition, the divergence of the Tasmanian and New Zealand mudfish appears to postdate the rifting of Gondwana and is best explained by marine dispersal during the Pliocene.

Molecular Phylogeny and Biogeography of the Tasmanian and New Zealand Mudfishes (Salmoniformes : Galaxiidae)

The phylogenetic affinities of the diadromous Tasmanian mudfish, Galaxias cleaveri, have long been problematic. Some systematists have suggested that this species is closely related to the morphologically similar but non-diadromous New Zealand mudfish genus, Neochanna, while others argued that the similarities represent convergent evolution. Most recently, the Tasmanian mudfish was allocated to Neochanna on morphological grounds. The current paper presents sequence data from two mitochondrial genes that support this decision, revealing a close phylogenetic relationship between Tasmanian and New Zealand mudfish. Molecular clock calibrations are used to examine hypotheses of mudfish evolution and biogeography. Estimated divergence times are consistent with the suggestion that Neochanna burrowsius and N. apoda were separated by the uplift of New Zealand’s southern Alps about five million years ago. In addition, the divergence of the Tasmanian and New Zealand mudfish appears to postdate the rifting of Gondwana and is best explained by marine dispersal during the Pliocene.

Two leaf pathogens of Ribes spp. in North America, Quasiphloeospora saximontanensis and Phloeosporella ribis

The generic name Quasiphloeospora, type species Q. saximontanensis comb. nov., is introduced for a species associated with foliar lesions on the forest weed Ribes viscosissimum and other species of Ribes. It is compared with similar genera and species of hyphomycetes and coelomycetes, especially Phloeosporella ribis comb. nov. with which it has been confused.

Elymus calderi: A New Species in the Triticeae (Poaceae)

Herbarium specimens identified as Agropyron yukonense or one of its synonyms consistently differ from the holotype and protologue of that name and resemble each other in their stiff, involute leaves, narrow, dark cauline nodal bands, and pilose paleas. This suggests that the non-holotype plants represent a new species. Cytogenetic analysis of root tip chromosomes from non-holotype plants revealed that they were tetraploids with 2n = 28. Analysis of genome-specific DNA suggested that it contained the St and H genomes, resembling Elymus s. str. in this regard, rather than the morphologically similar genus Roegneria which contains the St and Y genomes. Presence of the H genome and absence of the Y genome were supported by analysis of 70 low copy DNA sequences detected using sequence-tagged-site PCR analysis. Thus, morphologi- cal, cytogenetic, and molecular results support inclusion of the new species in Elymus. The name Elymus calderi is proposed, in honor of J.A. Calder, a taxonomist who worked extensively in western Canada. A description, illustration, and distribution map are presented. Annual and perennial grasses of the Triticeae are found in most temperate and subarctic regions of the world. The tribe is notorious for its widespread polyploidy and the tendency of its members to form hybrids of varying fertility. Our study was prompted by the discovery that all specimens identified as Agropyron yukonense Scribn. & Merr. (or one of its synonyms) in ALA, CAN, DAO, UTC, and V (herbarium codes from Holmgren et al. 1990) differed from the holotype of that taxon in characteristics described in the protologue of the species. This observation, combined with the morphological similarity of the non-holotype speci- mens to each other, suggested that the non- holotype specimens represent a different taxon from the holotype, one that had not yet been recognized. Our goal was to determine whether this was the case and, if so, to determine the genomic constitution of the new taxon and provide it with an appropriate name.