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Frithjof A S Sterrenburg - One of the best experts on this subject based on the ideXlab platform.

  • A comparative study of Pleurosigma subrectum and P. acus (Bacillariophyta)
    Phytotaxa, 2015
    Co-Authors: Frithjof A S Sterrenburg, Stuart R Stidolph, Eugenia A. Sar, Inés Sunesen
    Abstract:

    In continuation of an earlier paper on Pleurosigma species with an (almost) non-sigmoid valve and raphe sternum, a comparative study was made in LM and SEM of Pleurosigma subrectum and P. acus . For P. subrectum , slides and a subsample of the type material were examined. For P. acus no unmounted material permitting SEM investigation is extant; a sample containing specimens fully matching the type in LM was therefore used as epitype material for SEM. The original data on striation of P. acus are emended. No morphological differences indicating separate specific status of these two taxa were observed and P. acus is therefore here designated a heterotypic synonym of P. subrectum . From the data now available, this is a very widely distributed species. The study demonstrates the indispensable role of collections for investigations on the diversity and distribution of diatom species.

  • seven new species expand the morphological spectrum of haslea a comparison with gyrosigma and Pleurosigma bacillariophyta
    Phytotaxa, 2015
    Co-Authors: Frithjof A S Sterrenburg, Wulf E Herwig, Mary Ann Tiffany, Friedel Hinz, Paul E. Hargraves
    Abstract:

    Seven new Haslea species demonstrate that the genus has evolved a richer morphological repertoire than so far reported . H. feriarum sp. nov. has a valve contour suggesting an Amphora; H. staurosigmoidea sp. nov. has a sigmoid valve with a pseudostauros; H. tsukamotoi sp. nov. and the closely similar H. meteorou sp. nov. possess uniquely shaped external central raphe endings and a fully sideways-tilted internal raphe system; H. clevei sp. nov. and H. avium sp. nov. also have central raphe ending shapes not yet described in the genus; H. amicorum shows interrupted longitudinal fissures besides the continuous fissures characteristic of Haslea . A survey of the Haslea species described, for differentiation of our taxa, led to two conclusions: 1) the data in the protologue of H. indica Desikachary & Prema are spurious and 2) “Navicula” duerrenbergiana Hustedt is here transferred to the genus Haslea . The basic Haslea morphology is a sandwich-type valve, with a grate-like inner layer (here called basal layer ) and an outer layer (here called tegumental layer ) perforated by continuous longitudinal fissures. These two layers are shored by upright longitudinal “bulkheads”, here called saepes , seen to be perforated in the valves that permitted their observation. This morphology is closely similar to that of Gyrosigma (and Pleurosigma ). The great variety of central external raphe ending patterns in Haslea , Gyrosigma and Pleurosigma is shown and discussed.

  • analisis de los materiales tipo de Pleurosigma formosum y p decorum Pleurosigmataceae bacillariophyta
    Boletin de la Sociedad Argentina de Botanica, 2014
    Co-Authors: Frithjof A S Sterrenburg, Eugenia A. Sar, Inés Sunesen
    Abstract:

    The type materials of Pleurosigma formosum W. Smith and P. decorum W. Smith wereexamined. Both species were separated hitherto by size range, valve shape and stria density basedon light microscopy (LM) analysis. However, the type materials show some overlap in the size and striadensity ranges, with subtle differences in the oblique stria intersection angle, which is somewhat smallerfor P. decorum. Scanning electron microscopy (SEM) analysis shows that both species share severalultrastructural features such as a thick saddle-shaped central raphe nodule, very long overlapping centralraphe fissures, short hook-shaped terminal raphe fissures, general morphology of the internal hymenoccludedpores crossed by a recessed bar and presence of some scattered pairs of more deeply recessedpores lacking a bar. However, the type specimens differ in the internal morphology of the hymen-occludedareolar pores, circular, crossed by a recessed bar and rimmed in P. formosum and subcircular to elliptical,crossed by a less recessed bar, not rimmed in P. decorum. The SEM findings thus support Hendey’s viewthat P. decorum and P. formosum are separate but closely allied species.

  • Pleurosigma hinzianum sp. nov. and P. frenguellianum sp. nov. (Pleurosigmataceae, Bacillariophyta) from Argentinean coastal waters, in comparison with P. amara Stidolph and P. elongatum W. Smith
    European Journal of Phycology, 2014
    Co-Authors: Eugenia A. Sar, Frithjof A S Sterrenburg, Inés Sunesen
    Abstract:

    Two new marine diatom species from Argentinean coastal waters, Pleurosigma hinzianum Sterrenburg, Sunesen & Sar, sp. nov. and P. frenguellianum Sunesen, Sterrenburg & Sar, sp. nov., are described. The characters permitting their identification are specified, based on comparison with type material of the morphologically similar species P. amara Stidolph and P. elongatum W. Smith in the light (LM) and scanning electron microscope (SEM). New information on the type material of P. elongatum is presented and its taxonomic concept is emended. The main criteria for separation of the species discussed here are: valve outline, path of the raphe-sternum, raphe angle and angle of intersection of the oblique striae in LM; and external central and terminal raphe fissures, internal details of the central area, external and internal apical structure, and morphology of the hymen-occluded internal pores in SEM. The occurrence of these (and probably other) species in the genus Pleurosigma in net samples is adventitious and...

  • Pleurosigma guarreranum, sp. nov. (Pleurosigmataceae, Bacillariophyta), from the Gulf of San Matías, Argentina, and comparison with the allied species Pleurosigma exemptum and P. obesum
    European Journal of Phycology, 2013
    Co-Authors: Inés Sunesen, Frithjof A S Sterrenburg, Eugenia A. Sar
    Abstract:

    A new marine diatom, Pleurosigma guarreranum Sar, Sterrenburg & Sunesen, sp. nov., is described with light and electron microscopy from material collected in coastal waters of the Gulf of San Matias, Rio Negro Province, Argentina. Pleurosigma guarreranum resembles P. exemptum and P. obesum from the Philippines. Isotypes of P. exemptum and P. obesum deposited in the Albert Mann Collection, National Museum of Natural History, Smithsonian Institution (US), were examined with light microscopy. The observations supported a previous suggestion to include P. obesum as a heterotypic synonym of P. exemptum, which has priority. Since there is no available unmounted original material of P. exemptum, a comparative light microscopical analysis of P. guarreranum and the type material of P. exemptum was made. Despite some similarities, there are subtle differences in morphometric data, valve outline, raphe sternum pattern, and morphology of the central area. But especially, the two species consistently differ in the ang...

Inés Sunesen - One of the best experts on this subject based on the ideXlab platform.

  • A comparative study of Pleurosigma subrectum and P. acus (Bacillariophyta)
    Phytotaxa, 2015
    Co-Authors: Frithjof A S Sterrenburg, Stuart R Stidolph, Eugenia A. Sar, Inés Sunesen
    Abstract:

    In continuation of an earlier paper on Pleurosigma species with an (almost) non-sigmoid valve and raphe sternum, a comparative study was made in LM and SEM of Pleurosigma subrectum and P. acus . For P. subrectum , slides and a subsample of the type material were examined. For P. acus no unmounted material permitting SEM investigation is extant; a sample containing specimens fully matching the type in LM was therefore used as epitype material for SEM. The original data on striation of P. acus are emended. No morphological differences indicating separate specific status of these two taxa were observed and P. acus is therefore here designated a heterotypic synonym of P. subrectum . From the data now available, this is a very widely distributed species. The study demonstrates the indispensable role of collections for investigations on the diversity and distribution of diatom species.

  • analisis de los materiales tipo de Pleurosigma formosum y p decorum Pleurosigmataceae bacillariophyta
    Boletin de la Sociedad Argentina de Botanica, 2014
    Co-Authors: Frithjof A S Sterrenburg, Eugenia A. Sar, Inés Sunesen
    Abstract:

    The type materials of Pleurosigma formosum W. Smith and P. decorum W. Smith wereexamined. Both species were separated hitherto by size range, valve shape and stria density basedon light microscopy (LM) analysis. However, the type materials show some overlap in the size and striadensity ranges, with subtle differences in the oblique stria intersection angle, which is somewhat smallerfor P. decorum. Scanning electron microscopy (SEM) analysis shows that both species share severalultrastructural features such as a thick saddle-shaped central raphe nodule, very long overlapping centralraphe fissures, short hook-shaped terminal raphe fissures, general morphology of the internal hymenoccludedpores crossed by a recessed bar and presence of some scattered pairs of more deeply recessedpores lacking a bar. However, the type specimens differ in the internal morphology of the hymen-occludedareolar pores, circular, crossed by a recessed bar and rimmed in P. formosum and subcircular to elliptical,crossed by a less recessed bar, not rimmed in P. decorum. The SEM findings thus support Hendey’s viewthat P. decorum and P. formosum are separate but closely allied species.

  • Pleurosigma hinzianum sp. nov. and P. frenguellianum sp. nov. (Pleurosigmataceae, Bacillariophyta) from Argentinean coastal waters, in comparison with P. amara Stidolph and P. elongatum W. Smith
    European Journal of Phycology, 2014
    Co-Authors: Eugenia A. Sar, Frithjof A S Sterrenburg, Inés Sunesen
    Abstract:

    Two new marine diatom species from Argentinean coastal waters, Pleurosigma hinzianum Sterrenburg, Sunesen & Sar, sp. nov. and P. frenguellianum Sunesen, Sterrenburg & Sar, sp. nov., are described. The characters permitting their identification are specified, based on comparison with type material of the morphologically similar species P. amara Stidolph and P. elongatum W. Smith in the light (LM) and scanning electron microscope (SEM). New information on the type material of P. elongatum is presented and its taxonomic concept is emended. The main criteria for separation of the species discussed here are: valve outline, path of the raphe-sternum, raphe angle and angle of intersection of the oblique striae in LM; and external central and terminal raphe fissures, internal details of the central area, external and internal apical structure, and morphology of the hymen-occluded internal pores in SEM. The occurrence of these (and probably other) species in the genus Pleurosigma in net samples is adventitious and...

  • Pleurosigma guarreranum, sp. nov. (Pleurosigmataceae, Bacillariophyta), from the Gulf of San Matías, Argentina, and comparison with the allied species Pleurosigma exemptum and P. obesum
    European Journal of Phycology, 2013
    Co-Authors: Inés Sunesen, Frithjof A S Sterrenburg, Eugenia A. Sar
    Abstract:

    A new marine diatom, Pleurosigma guarreranum Sar, Sterrenburg & Sunesen, sp. nov., is described with light and electron microscopy from material collected in coastal waters of the Gulf of San Matias, Rio Negro Province, Argentina. Pleurosigma guarreranum resembles P. exemptum and P. obesum from the Philippines. Isotypes of P. exemptum and P. obesum deposited in the Albert Mann Collection, National Museum of Natural History, Smithsonian Institution (US), were examined with light microscopy. The observations supported a previous suggestion to include P. obesum as a heterotypic synonym of P. exemptum, which has priority. Since there is no available unmounted original material of P. exemptum, a comparative light microscopical analysis of P. guarreranum and the type material of P. exemptum was made. Despite some similarities, there are subtle differences in morphometric data, valve outline, raphe sternum pattern, and morphology of the central area. But especially, the two species consistently differ in the ang...

  • diatomeas de ambientes marinos costeros de argentina especies del genero Pleurosigma Pleurosigmataceae
    Boletin de la Sociedad Argentina de Botanica, 2013
    Co-Authors: Eugenia A. Sar, Frithjof A S Sterrenburg, Andrea S Lavigne, Inés Sunesen
    Abstract:

    Fil: Sar, Eugenia Alicia. Universidad Nacional de la Plata. Facultad de Ciencias Naturales y Museo. Division Ficologia; Argentina. Consejo Nacional de Investigaciones Cientificas y Tecnicas; Argentina

Eugenia A. Sar - One of the best experts on this subject based on the ideXlab platform.

  • A comparative study of Pleurosigma subrectum and P. acus (Bacillariophyta)
    Phytotaxa, 2015
    Co-Authors: Frithjof A S Sterrenburg, Stuart R Stidolph, Eugenia A. Sar, Inés Sunesen
    Abstract:

    In continuation of an earlier paper on Pleurosigma species with an (almost) non-sigmoid valve and raphe sternum, a comparative study was made in LM and SEM of Pleurosigma subrectum and P. acus . For P. subrectum , slides and a subsample of the type material were examined. For P. acus no unmounted material permitting SEM investigation is extant; a sample containing specimens fully matching the type in LM was therefore used as epitype material for SEM. The original data on striation of P. acus are emended. No morphological differences indicating separate specific status of these two taxa were observed and P. acus is therefore here designated a heterotypic synonym of P. subrectum . From the data now available, this is a very widely distributed species. The study demonstrates the indispensable role of collections for investigations on the diversity and distribution of diatom species.

  • analisis de los materiales tipo de Pleurosigma formosum y p decorum Pleurosigmataceae bacillariophyta
    Boletin de la Sociedad Argentina de Botanica, 2014
    Co-Authors: Frithjof A S Sterrenburg, Eugenia A. Sar, Inés Sunesen
    Abstract:

    The type materials of Pleurosigma formosum W. Smith and P. decorum W. Smith wereexamined. Both species were separated hitherto by size range, valve shape and stria density basedon light microscopy (LM) analysis. However, the type materials show some overlap in the size and striadensity ranges, with subtle differences in the oblique stria intersection angle, which is somewhat smallerfor P. decorum. Scanning electron microscopy (SEM) analysis shows that both species share severalultrastructural features such as a thick saddle-shaped central raphe nodule, very long overlapping centralraphe fissures, short hook-shaped terminal raphe fissures, general morphology of the internal hymenoccludedpores crossed by a recessed bar and presence of some scattered pairs of more deeply recessedpores lacking a bar. However, the type specimens differ in the internal morphology of the hymen-occludedareolar pores, circular, crossed by a recessed bar and rimmed in P. formosum and subcircular to elliptical,crossed by a less recessed bar, not rimmed in P. decorum. The SEM findings thus support Hendey’s viewthat P. decorum and P. formosum are separate but closely allied species.

  • Pleurosigma hinzianum sp. nov. and P. frenguellianum sp. nov. (Pleurosigmataceae, Bacillariophyta) from Argentinean coastal waters, in comparison with P. amara Stidolph and P. elongatum W. Smith
    European Journal of Phycology, 2014
    Co-Authors: Eugenia A. Sar, Frithjof A S Sterrenburg, Inés Sunesen
    Abstract:

    Two new marine diatom species from Argentinean coastal waters, Pleurosigma hinzianum Sterrenburg, Sunesen & Sar, sp. nov. and P. frenguellianum Sunesen, Sterrenburg & Sar, sp. nov., are described. The characters permitting their identification are specified, based on comparison with type material of the morphologically similar species P. amara Stidolph and P. elongatum W. Smith in the light (LM) and scanning electron microscope (SEM). New information on the type material of P. elongatum is presented and its taxonomic concept is emended. The main criteria for separation of the species discussed here are: valve outline, path of the raphe-sternum, raphe angle and angle of intersection of the oblique striae in LM; and external central and terminal raphe fissures, internal details of the central area, external and internal apical structure, and morphology of the hymen-occluded internal pores in SEM. The occurrence of these (and probably other) species in the genus Pleurosigma in net samples is adventitious and...

  • Pleurosigma guarreranum, sp. nov. (Pleurosigmataceae, Bacillariophyta), from the Gulf of San Matías, Argentina, and comparison with the allied species Pleurosigma exemptum and P. obesum
    European Journal of Phycology, 2013
    Co-Authors: Inés Sunesen, Frithjof A S Sterrenburg, Eugenia A. Sar
    Abstract:

    A new marine diatom, Pleurosigma guarreranum Sar, Sterrenburg & Sunesen, sp. nov., is described with light and electron microscopy from material collected in coastal waters of the Gulf of San Matias, Rio Negro Province, Argentina. Pleurosigma guarreranum resembles P. exemptum and P. obesum from the Philippines. Isotypes of P. exemptum and P. obesum deposited in the Albert Mann Collection, National Museum of Natural History, Smithsonian Institution (US), were examined with light microscopy. The observations supported a previous suggestion to include P. obesum as a heterotypic synonym of P. exemptum, which has priority. Since there is no available unmounted original material of P. exemptum, a comparative light microscopical analysis of P. guarreranum and the type material of P. exemptum was made. Despite some similarities, there are subtle differences in morphometric data, valve outline, raphe sternum pattern, and morphology of the central area. But especially, the two species consistently differ in the ang...

  • diatomeas de ambientes marinos costeros de argentina especies del genero Pleurosigma Pleurosigmataceae
    Boletin de la Sociedad Argentina de Botanica, 2013
    Co-Authors: Eugenia A. Sar, Frithjof A S Sterrenburg, Andrea S Lavigne, Inés Sunesen
    Abstract:

    Fil: Sar, Eugenia Alicia. Universidad Nacional de la Plata. Facultad de Ciencias Naturales y Museo. Division Ficologia; Argentina. Consejo Nacional de Investigaciones Cientificas y Tecnicas; Argentina

Sunesen Inés - One of the best experts on this subject based on the ideXlab platform.

  • Diatoms from marine coastal environments of Argentina: Species of the genus Pleurosigma (Pleurosigmataceae)
    2020
    Co-Authors: Sar, Eugenia Alicia, Sterrenburg, Frithjof A. S., Lavigne, Andrea Susana, Sunesen Inés
    Abstract:

    Este estudio está enfocado en el análisis de la morfología, taxonomía y distribución de las especies pertenecientes al género de diatomeas Pleurosigma W. Smith presentes en aguas marinas costeras de la Argentina. Las muestras de red fueron obtenidas en la capa superficial de la columna de agua en varias estaciones costeras de las provincias de Buenos Aires y Río Negro. Materiales procesados y no procesados fueron examinados con microscopía óptica y electrónica de barrido. Las especies determinadas fueron Pleurosigma decorum W. Smith, P. distinguendum Hustedt, P. inflatum Shadbolt, P. inscriptura M. A. Harper, P. normanii Ralfs y P. simonsenii Hasle. Dos nuevos taxa son erigidos. Pleurosigma patagonicum var. paucistriatum nov. var. es comparada con el material tipo de Pleurosigma patagonicum (Ferrario & Sar) Sterrenburg & Sar var. patagonicum y P. perlucidum nov. spec. es comparada con P. elongatum W. Smith, P. delicatulum W. Smith, P. amara Stidolph y P. brunii H. Peragallo sobre la base del análisis de materiales tipo y/o protologos. Nuevas observaciones sobre Pleurosigma decorum, P. distinguendum, P. inflatum, P. inscriptura y P. normanii son incluidas y las diferencias con especies relacionadas son discutidas. Pleurosigma inflatum es citada por primera vez para Argentina y P. distinguendum y P. inscriptura son citadas por primera vez para el Océano Atlántico Sur.Diatoms from marine coastal environments of Argentina. Species of the genus Pleurosigma (Pleurosigmataceae). This study focuses on the analysis of the morphology, taxonomy and distribution of species belonging to the diatom genus Pleurosigma W. Smith found in marine coastal waters of Argentina. Net samples were collected from the surface layer of the water column at several coastal stations in Buenos Aires and Río Negro Provinces. Unprocessed and cleaned materials were examined by light and scanning electron microscopy. Species identified were Pleurosigma decorum W. Smith, P. distinguendum Hustedt, P. inflatum Shadbolt, P. inscriptura M. A. Harper, P. normanii Ralfs and P. simonsenii Hasle. Two new taxa are described. Pleurosigma patagonicum var. paucistriatum nov. var. is compared with type material of Pleurosigma patagonicum (Ferrario & Sar) Sterrenburg & Sar var. patagonicum and P. perlucidum nov. spec. is compared with P. elongatum W. Smith, P. delicatulum W. Smith, P. amara Stidolph and P. brunii H. Peragallo based on type materials and/or protologues. New observations on Pleurosigma decorum, P. distinguendum, P. inflatum, P. inscriptura and P. normanii are included and differences from related species are discussed. P. inflatum is recorded for the first time from Argentina and Pleurosigma distinguendum and P. inscriptura are recorded for first time from the South Atlantic Ocean.Facultad de Ciencias Naturales y Muse

  • Analysis of type material of Pleurosigma formosum and P. decorum (Pleurosigmataceae, Bacillariophyta)
    2020
    Co-Authors: Sterrenburg, Frithjof A. S., Sar, Eugenia Alicia, Sunesen Inés
    Abstract:

    Los materiales tipo de Pleurosigma formosum W. Smith y P. decorum W. Smith fueron examinados. Ambas especies fueron separadas hasta ahora por el rango de tamaño, la forma de la valva y la densidad de las estrías sobre la base de su análisis con microscopio óptico (MO). Sin embargo, los materiales tipo muestran alguna superposición en los rangos de tamaño y densidad de estrías, con sutiles diferencias en el ángulo de intersección de las estrías oblicuas, el cual es algo más pequeño en P. decorum. El análisis con microscopio electrónico de barrido (MEB) muestra que ambas especies comparten algunos caracteres ultraestructurales tales como el engrosamiento en forma de silla de montar del nódulo central del rafe, la amplia superposición de las fisuras centrales del rafe, la forma de las fisuras terminales del rafe, en gancho corto, la morfología general de los poros internos ocluidos por un himen cruzado por una barra hundida y la presencia de algunos pares esparcidos de poros más profundamente excavados, carentes de barra. Sin embargo, los especímenes tipo difieren en la morfología interna de los poros areolares ocluidos por un himen. Estos son circulares, cruzados por una barra hundida y con bordes engrosados en P. formosum y sub-circulares a elípticos, cruzados por una barra menos hundida y sin bordes engrosados en P. decorum. Los resultados del análisis con MEB apoyan el punto de vista de Hendey acerca de que P. decorum y P. formosum son especies separadas pero cercanamente relacionadas.The type materials of Pleurosigma formosum W. Smith and P. decorum W. Smith were examined. Both species were separated hitherto by size range, valve shape and stria density based on light microscopy (LM) analysis. However, the type materials show some overlap in the size and stria density ranges, with subtle differences in the oblique stria intersection angle, which is somewhat smaller for P. decorum. Scanning electron microscopy (SEM) analysis shows that both species share several ultrastructural features such as a thick saddle-shaped central raphe nodule, very long overlapping central raphe fissures, short hook-shaped terminal raphe fissures, general morphology of the internal hymenoccluded pores crossed by a recessed bar and presence of some scattered pairs of more deeply recessed pores lacking a bar. However, the type specimens differ in the internal morphology of the hymen-occluded areolar pores, circular, crossed by a recessed bar and rimmed in P. formosum and subcircular to elliptical, crossed by a less recessed bar, not rimmed in P. decorum. The SEM findings thus support Hendey’s view that P. decorum and P. formosum are separate but closely allied species.Facultad de Ciencias Naturales y Muse

  • Pleurosigma guarreranum, sp. nov. (Pleurosigmataceae, Bacillariophyta), from the Gulf of San Matías, Argentina, and comparison with the allied species Pleurosigma exemptum and P. obesum
    2019
    Co-Authors: Sunesen Inés, Sterrenburg, Frithjof A. S., Sar, Eugenia A.
    Abstract:

    A new marine diatom, Pleurosigma guarreranum Sar, Sterrenburg & Sunesen, sp. nov., is described with light and electron microscopy from material collected in coastal waters of the Gulf of San Matías, Río Negro Province, Argentina. Pleurosigma guarreranum resembles P. exemptum and P. obesum from the Philippines. Isotypes of P. exemptum and P. obesum deposited in the Albert Mann Collection, National Museum of Natural History, Smithsonian Institution (US), were examined with light microscopy. The observations supported a previous suggestion to include P. obesum as a heterotypic synonym of P. exemptum, which has priority. Since there is no available unmounted original material of P. exemptum, a comparative light microscopical analysis of P. guarreranum and the type material of P. exemptum was made. Despite some similarities, there are subtle differences in morphometric data, valve outline, raphe sternum pattern, and morphology of the central area. But especially, the two species consistently differ in the angle of intersection of the oblique striae, justifying a separate taxonomic position. Pleurosigma guarreranum was also compared with another species belonging to the section Formosi, P. decorum, similar in valve outline, raphe sternum pattern and angle of intersection of the oblique striae.Facultad de Ciencias Naturales y Muse

  • A comparative study of Pleurosigma subrectum and P. acus (Bacillariophyta)
    'Magnolia Press', 2015
    Co-Authors: Sterrenburg, Frithjof A. S., Sar, Eugenia Alicia, Stidolph, Stuart R., Sunesen Inés
    Abstract:

    In continuation of an earlier paper on Pleurosigma species with an (almost) non-sigmoid valve and raphe sternum, a comparative study was made in LM and SEM of Pleurosigma subrectum and P. acus. For P. subrectum, slides and a subsample of the type material were examined. For P. acus no unmounted material permitting SEM investigation is extant; a sample containing specimens fully matching the type in LM was therefore used as epitype material for SEM. The original data on striation of P. acus are emended. No morphological differences indicating separate specific status of these two taxa were observed and P. acus is therefore here designated a heterotypic synonym of P. subrectum. From the data now available, this is a very widely distributed species. The study demonstrates the indispensable role of collections for investigations on the diversity and distribution of diatom species.Fil: Sterrenburg, Frithjof A. S.. No especifica;Fil: Stidolph, Stuart R.. No especifica;Fil: Sar, Eugenia Alicia. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División Ficología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Sunesen, Inés. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División Ficología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

  • Pleurosigma hinzianum sp. nov. and P. frenguellianum sp. nov. (Pleurosigmataceae, Bacillariophyta) from Argentinean coastal waters, in comparison with P. amara Stidolph and P. elongatum W. Smith
    'Informa UK Limited', 2014
    Co-Authors: Sar, Eugenia Alicia, Sterrenburg, Frithjof A. S., Sunesen Inés
    Abstract:

    Two new marine diatom species from Argentinean coastal waters, Pleurosigma hinzianum Sterrenburg, Sunesen & Sar sp. nov. and P. frenguellianum Sunesen, Sterrenburg & Sar sp.nov., are described. The characters permitting their identification are specified, based on comparison with the type material of the two morphologically similar species P. amara Stidolph and P. elongatum W. Smith in the light- (LM) and scanning electron microscope (SEM). New information on the type material of P. elongatum is presented and its taxonomic concept is emended. The main criteria for separation of the species discussed here are: valve outline, path of the raphe-sternum, raphe angle and angle of intersection of the oblique striae in LM; and external central and terminal raphe fissures, internal details of the central area, external and internal apical structure, and morphology of the hymen-occluded internal pores in SEM. The occurrence of these ?and probably other? species in the genus Pleurosigma in net samples is adventitious and not indicative of a true planktonic mode of life.Fil: Sar, Eugenia Alicia. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División Ficología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; ArgentinaFil: Sterrenburg, Frithjof A. S.. No especifíca;Fil: Sunesen, Inés. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División Ficología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; Argentin

Geraldine Reid - One of the best experts on this subject based on the ideXlab platform.

  • Pleurosigma obscurum w smith or gyrosigma obscurum w smith griffith et henfrey the tale of two genera
    Diatom Research, 2004
    Co-Authors: Geraldine Reid
    Abstract:

    The generic placement of Gyrosigma obscurum (W. Smith) Griffith & Henfrey has been questioned in recent years, its position moving between Gyrosigma and Pleurosigma. The recent paper of Reid (2002a) caused some concern and Sterrenburg proposed that obscurum should be placed in Pleurosigma. This paper reinvestigates the claims of both Reid and Sterrenburg to conclude that the generic placement of obscurum is clearly more closely related to species of Gyrosigma than to species of Pleurosigma. Reanalyses of Reid's data set substituting the character coding advocated by Sterrenburg for striae arrangement and using the concepts of Sterrenburg in the cladistic analysis still shows that obscurum is more closely related to species of Gyrosigma than to species of Pleurosigma.

  • systematics of the gyrosigma balticum complex bacillariophyta including three new species
    Phycological Research, 2003
    Co-Authors: Geraldine Reid, David M. Williams
    Abstract:

    SUMMARY Three new species in the genus Gyrosigma Hassall (G. caliG. Reid sp. nov., G. gibbyiG. Reid sp. nov. and G. murphyi G. Reid sp. nov) are described. A cladistic analysis on the basis of 10 morphological characters, was undertaken to investigate the interrelationships of these new species within Gyrosigma. As well as ‘standard’ cladistic analysis, which apportions equal weight to all characters, a posteriori differential weighting was also investigated. Pleurosigma subtilis Brebisson is transferred to Gyrosigma, as G. subtile (Brebisson) G. Reid comb. nov., because it is more closely related to other species of Gyrosigma than to Pleurosigma Smith. G. balticum var. californicum Grunow in Cleve and Moller is elevated to specific status [as G. californicum (Grunow in Cleve and Moller) G. Reid stat. nov.], because it does not form a monophyletic group with G. balticum (Ehrenberg) Rabenhorst.

  • Four new species of Pleurosigma (Bacillariophyta) from Alexandria, Egypt
    Botanical Journal of the Linnean Society, 2002
    Co-Authors: Geraldine Reid
    Abstract:

    Four new species of Pleurosigma are described from the region of Alexandria in Egypt: P. williamsiisp. nov., P. mariutensissp. nov., P. ramlehensissp. nov. and P. rushdyensissp. nov. The taxa had been previously misidentified as P. rigidum W. Sm., P. elongatum W. Sm., P. speciosum var. sumatricum H. Perag. and P. formosum W. Sm., respectively. Due to the close resemblance of P. williamsii, P. mariutensis, P. ramlehensis and P. rushdyensis to P. rigidum, P. elongatum, P. speciosum var. sumatricum and P. formosum and the lack of good illustrations of these previously described species, their valvar features are shown and discussed in relation to the new taxa. © 2002 The Linnean Society of London, Botanical Journal of the Linnean Society, 2002, 140, 77–92.