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Frithjof A S Sterrenburg - One of the best experts on this subject based on the ideXlab platform.
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Gyrosigma peisonis var major var nov a new variety of Gyrosigma peisonis bacillariophyta from lake qinghai china
Phytotaxa, 2016Co-Authors: Yumei Peng, Patrick Rioual, Frithjof A S SterrenburgAbstract:The morphology and ultrastructure of Gyrosigma peisonis var. major var . nov ., a new variety of Gyrosigma peisonis found in Lake Qinghai (China), are described here on the basis of light and scanning electron microscopy. Most of the morphological features of this new variety are identical to those of the nominal variety Gyrosigma peisonis var. peisonis , but the variety major differs in its distinctly larger cell size and its higher value for the longitudinal/transverse stria density ratio, however. The seasonal variation of this taxon, which was investigated by a sediment-trap study is also discussed.
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seven new species expand the morphological spectrum of haslea a comparison with Gyrosigma and pleurosigma bacillariophyta
Phytotaxa, 2015Co-Authors: Frithjof A S Sterrenburg, Wulf E Herwig, Mary Ann Tiffany, Friedel Hinz, Paul E HargravesAbstract: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.
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typification and taxonomy of Gyrosigma tenuissimum w sm j w griffith henfr comparison with Gyrosigma coelophilum n okamoto nagumo and description of two new taxa Gyrosigma tenuissimum var gundulae var nov and Gyrosigma baculum sp nov pleurosigmatacea
Phytotaxa, 2014Co-Authors: Frithjof A S Sterrenburg, Myriam De Haan, Wulf E Herwig, Paul E HargravesAbstract:Gyrosigma tenuissimum (W.Sm.) J.W.Griffith & Henfr. was examined in the original material and an emended description is presented. Its protologue contains an error of taxonomic significance: in the type material, the valve and raphe sternum do not show the considerable flexure described and illustrated in Smith (1853). A comparison with Gyrosigma coelophilum N. Okamoto & Nagumo revealed that the latter, although similar in several characters, differs sufficiently in others to warrant separate specific status. Descriptions of two new taxa are given: Gyrosigma tenuissimum var. gundulae var. nov. and Gyrosigma baculum sp. nov . Both show very fine longitudinal striae at or beyond the limit of ordinary light microscopy and are practically non-sigmoid
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Typification and taxonomy of Gyrosigma tenuissimum (W. Sm.) J.W. Griffith & Henfr., comparison with Gyrosigma coelophilum N. Okamoto & Nagumo and description of two new taxa: Gyrosigma tenuissimum var. gundulae var. nov. and Gyrosigma baculum sp. nov
Phytotaxa, 2014Co-Authors: Frithjof A S Sterrenburg, Myriam De Haan, Wulf E Herwig, Paul E HargravesAbstract:Gyrosigma tenuissimum (W.Sm.) J.W.Griffith & Henfr. was examined in the original material and an emended description is presented. Its protologue contains an error of taxonomic significance: in the type material, the valve and raphe sternum do not show the considerable flexure described and illustrated in Smith (1853). A comparison with Gyrosigma coelophilum N. Okamoto & Nagumo revealed that the latter, although similar in several characters, differs sufficiently in others to warrant separate specific status. Descriptions of two new taxa are given: Gyrosigma tenuissimum var. gundulae var. nov. and Gyrosigma baculum sp. nov . Both show very fine longitudinal striae at or beyond the limit of ordinary light microscopy and are practically non-sigmoid
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typification and taxonomy of Gyrosigma fasciola ehrenberg j w griffith et henfrey
Diatom Research, 2005Co-Authors: Regine Jahn, Frithjof A S Sterrenburg, Wolfhenning KusberAbstract:Based on typification in Ehrenberg's original material, the nomenclature and taxonomy of Gyrosigma fasciola (Ehrenberg) J.W. Griffith et Henfrey are discussed. This diatom is compared to two morphologically similar taxa, Gyrosigma sulcatum (Grunow in Cleve & Grunow) Frenguelli and Gyrosigma arcuatum (Donkin) Sterrenburg, which is here recombined on the basis of a type study. It showed that taxonomic continuity has been ensured for Ehrenberg's species for more than 150 years.
Paul E Hargraves - One of the best experts on this subject based on the ideXlab platform.
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seven new species expand the morphological spectrum of haslea a comparison with Gyrosigma and pleurosigma bacillariophyta
Phytotaxa, 2015Co-Authors: Frithjof A S Sterrenburg, Wulf E Herwig, Mary Ann Tiffany, Friedel Hinz, Paul E HargravesAbstract: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.
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typification and taxonomy of Gyrosigma tenuissimum w sm j w griffith henfr comparison with Gyrosigma coelophilum n okamoto nagumo and description of two new taxa Gyrosigma tenuissimum var gundulae var nov and Gyrosigma baculum sp nov pleurosigmatacea
Phytotaxa, 2014Co-Authors: Frithjof A S Sterrenburg, Myriam De Haan, Wulf E Herwig, Paul E HargravesAbstract:Gyrosigma tenuissimum (W.Sm.) J.W.Griffith & Henfr. was examined in the original material and an emended description is presented. Its protologue contains an error of taxonomic significance: in the type material, the valve and raphe sternum do not show the considerable flexure described and illustrated in Smith (1853). A comparison with Gyrosigma coelophilum N. Okamoto & Nagumo revealed that the latter, although similar in several characters, differs sufficiently in others to warrant separate specific status. Descriptions of two new taxa are given: Gyrosigma tenuissimum var. gundulae var. nov. and Gyrosigma baculum sp. nov . Both show very fine longitudinal striae at or beyond the limit of ordinary light microscopy and are practically non-sigmoid
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Typification and taxonomy of Gyrosigma tenuissimum (W. Sm.) J.W. Griffith & Henfr., comparison with Gyrosigma coelophilum N. Okamoto & Nagumo and description of two new taxa: Gyrosigma tenuissimum var. gundulae var. nov. and Gyrosigma baculum sp. nov
Phytotaxa, 2014Co-Authors: Frithjof A S Sterrenburg, Myriam De Haan, Wulf E Herwig, Paul E HargravesAbstract:Gyrosigma tenuissimum (W.Sm.) J.W.Griffith & Henfr. was examined in the original material and an emended description is presented. Its protologue contains an error of taxonomic significance: in the type material, the valve and raphe sternum do not show the considerable flexure described and illustrated in Smith (1853). A comparison with Gyrosigma coelophilum N. Okamoto & Nagumo revealed that the latter, although similar in several characters, differs sufficiently in others to warrant separate specific status. Descriptions of two new taxa are given: Gyrosigma tenuissimum var. gundulae var. nov. and Gyrosigma baculum sp. nov . Both show very fine longitudinal striae at or beyond the limit of ordinary light microscopy and are practically non-sigmoid
F A S Sterrenburg - One of the best experts on this subject based on the ideXlab platform.
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Gyrosigma xiamenense sp nov bacillariophyta from the middle intertidal zone xiamen bay southern china
Phytotaxa, 2015Co-Authors: F A S Sterrenburg, Bangqin HuangAbstract:Gyrosigma xiamenense sp . nov ., a new diatom species from the middle intertidal zone, Xiamen Bay, southern China, was studied by light and scanning electron microscopy. The valves are large and sigmoid, with parallel sides. The raphe sternum has single curvature. Externally, a row of round pores is present on the mantle; isomorphic proximal raphe fissures turn first in opposite directions, then both final parts of the fissures run nearly parallel to the longitudinal striae. Internally, a row of areolae closest to the raphe sternum is capped by small projections on the primary side whilst these are absent on the secondary side; proximal raphe endings are first club-shaped, then the final parts of the two raphe endings form two T-shaped slits being separated from the club-shaped part by a tiny bridge; there is a vermiform bar in the middle of the raphe nodule. G . xiamenense is epipelic and lives in marine habitats.
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studies on the diatom genera Gyrosigma and pleurosigma bacillariophyceae pleurosigma strigosum w smith and some presumptive relatives
Micropaleontology, 2003Co-Authors: F A S SterrenburgAbstract:Abstract Pleurosigma strigosum W. Smith is not a variety of P. angulatum (Quekett) W. Smith but a different species, as confirmed in SEM. This conclusion agrees with that of Hendey (1964), who typified the species. P. finmarchicum Cleve in Cleve and Moller 1882 does not show specific differences from P. strigosum. This paper gives descriptions and criteria for differentiation for P. strigosum, P. acutum Norman ex Ralfs in Pritchard, P. latum Cleve in Cleve et Grunow and P. sabangi Meister, a species that is not restricted to tropical seas - hitherto its only record. The second record of P. sterrenburgii Stidolph, from a truly antipodal locality, also raises questions regarding its distribution.
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studies on the genera pleurosigma and Gyrosigma the types of shadbolt and related taxa
Proceedings of the Academy of Natural Sciences of Philadelphia, 2001Co-Authors: F A S SterrenburgAbstract:Abstract The two species of Pleurosigma described by G. Shadbolt have been critically examined in the type material with LM and with SEM for specimens conforming to the types in LM. A comparison of P. inflatum Shadbolt and P. naviculaceum Brebisson did not reveal any specific difference; the former taxon has priority while the latter is designated a synonym. The protologue of P. diverse-striatum Meister matches that of P. inflatum, but new findings validate its separate status. Pleurosigma diverse-striatum differs from other members of the genus by its areolar morphology. Its status as a synonym of P. aequatoriale Cleve will be clarified in a future paper. Pleurosigma validum Shadbolt is shown to be a synonym of P. rigidum W. Smith. Lectotypes are designated for Pleurosigma inflatum Shadbolt, 1853, Pleurosigma naviculaceum Brebisson, 1854, and Pleurosigma validum Shadbolt, 1853; and Pleurosigma diverse-striatum Meister, 1934, is typified.
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studies on the genera Gyrosigma and pleurosigma bacillariophyceae rules controlling raphe fissure morphogenesis in Gyrosigma
Diatom Research, 1993Co-Authors: F A S SterrenburgAbstract:The type of central raphe fissure deflection distinguishes two major sections of the genus Gyrosigma: one containing dimorphic, the other isomorphic species. Both dimorphism and isomorphism are governed by strict rules. Isomorphic species exclusively show deflection to the convexity of the raphe sternum, dimorphic Gyrosigmas exhibit a “handedness”, i.e. the central raphe fissures exclusively deflect to the left in all species examined.
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studies on the genera Gyrosigma and pleurosigma bacillariophyceae the identity of pleurosigma obscurum w smith
Diatom Research, 1993Co-Authors: F A S SterrenburgAbstract:The typification of Pleurosigma obscurum W. Smith is discussed with reference to material collected by W. Smith. The placing of the species in the genus Gyrosigma in recent publications is incorrect. All intact cells of this organism were collected in non-marine samples. Claims in the literature for a marine-brackish ecology of this organism may be due to the fact that marine-brackish environments harbour several species that cannot be separated from P. obscurum using traditional species criteria.
Bangqin Huang - One of the best experts on this subject based on the ideXlab platform.
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Gyrosigma xiamenense sp nov bacillariophyta from the middle intertidal zone xiamen bay southern china
Phytotaxa, 2015Co-Authors: F A S Sterrenburg, Bangqin HuangAbstract:Gyrosigma xiamenense sp . nov ., a new diatom species from the middle intertidal zone, Xiamen Bay, southern China, was studied by light and scanning electron microscopy. The valves are large and sigmoid, with parallel sides. The raphe sternum has single curvature. Externally, a row of round pores is present on the mantle; isomorphic proximal raphe fissures turn first in opposite directions, then both final parts of the fissures run nearly parallel to the longitudinal striae. Internally, a row of areolae closest to the raphe sternum is capped by small projections on the primary side whilst these are absent on the secondary side; proximal raphe endings are first club-shaped, then the final parts of the two raphe endings form two T-shaped slits being separated from the club-shaped part by a tiny bridge; there is a vermiform bar in the middle of the raphe nodule. G . xiamenense is epipelic and lives in marine habitats.
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Gyrosigma rostratum sp nov bacillariophyta from the low intertidal zone xiamen bay southern china
Phytotaxa, 2015Co-Authors: David M Williams, Bangqin HuangAbstract:Gyrosigma rostratum , sp. nov. , a new diatom species from the low intertidal zone, Xiamen Bay, southern China, was studied with light and scanning electron microscopy. The valves are lanceolate with protracted rostrate apices, symmetrical to both apical and transapical axis, not sigmoid. The raphe is straight, with a raphe angle of approximately two degrees. The external central raphe endings turn in the same direction and are isomorphic. The unique characteristic of the valve is that a conopeum (a lunate flap of silica, approximately 0.8–1.1 µm wide by 4.4–4.8 µm long) covers the terminal axial area and two rows of areolae near each apex. Gyrosigma rostratum is epipsammic and lives in marine habitats.
Gerd Liebezeit - One of the best experts on this subject based on the ideXlab platform.
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Biochemical characterisation and fatty acid profiles of 25 benthic marine diatoms isolated from the Solthörn tidal flat (southern North Sea)
Journal of Applied Phycology, 2012Co-Authors: Bettina Scholz, Gerd LiebezeitAbstract:Twenty-five intertidal diatom species were isolated from the Solthorn tidal flat (Lower Saxony, southern North Sea) and grown in semi-continuous cultures under standardised conditions, in order to observe differences in their biochemical gross compositions (e.g. protein, lipid, carbohydrate and ash contents). Composition, expressed as % dry weight, indicated that the majority of species (52 %) contained only 30 %) were found for Amphora exigua, Gyrosigma spenceri, Pleurosigma angulatum and Gyrosigma littorale. Glucose, galactose, mannose and ribose constituted the majority of the sugars detected, although the levels of these varied between species. Lipid class composition showed high concentrations of phospholipids and galactolipids as major constituents (19–22 % and 40–43 % of total lipids). The major fatty acids in most species were 14:0, 16:0, 16:1(n-7) and 20:5(n-3). Significant differences in biochemical gross compositions were found in the temperature (10, 30 °C) and salinity tests (20, 35 PSU), suggesting special intracellular acclimatisation processes that provide possible explanations for the adaptability of the species to environmental variations and the distinct differences in the diatom assemblages.
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Microphytobenthic dynamics in a Wadden Sea intertidal flat – Part I: Seasonal and spatial variation of diatom communities in relation to macronutrient supply
European Journal of Phycology, 2012Co-Authors: Bettina Scholz, Gerd LiebezeitAbstract:The benthic diatoms composition of the surface sediments were sampled at two-weekly intervals from May 2008 to May 2009 at ten stations along a transect across the intertidal zone of the Solthorn tidal flat (southern North Sea, Germany). Inorganic macronutrients (nitrate, nitrite, silicic acid and reactive dissolved phosphate) in the overlying water showed a distinct seasonal cycle, with high winter and low summer values. The benthic diatom assemblages exhibited both seasonal and spatial distribution patterns, showing distinctive differences in species composition among summer, autumn, winter and spring communities. Independent of season, all structures were characterized by the dominance of small epipelic species such as Navicula phyllepta, N. digitoradiata, N. gregaria and N. salinicola, with seasonal successions of secondary species, including several larger benthic (e.g. Pleurosigma angulatum, Gyrosigma peisonis) and pelagic species (Plagiogramma and Thalassionema). In addition, the communities contai...
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Growth responses of 25 benthic marine Wadden Sea diatoms isolated from the Solthörn tidal flat (southern North Sea) in relation to varying culture conditions
Diatom Research, 2012Co-Authors: Bettina Scholz, Gerd LiebezeitAbstract:The unconsolidated sediment of intertidal mudflats constitutes a highly unstable environment, due to continuously changing water levels and currents, as well as temporary exposure to the air. As a consequence, diatoms inhabiting marine intertidal areas are subjected to wide variations in temperature, surface light intensity and salinity due to exposure at low tide. In order to determine the adaptive potential of these organisms, cultures of 25 benthic marine diatom species present in the Solthorn tidal flat in the years 2008/2009 were chosen to study the effect of different abiotic conditions. As expected, the interspecific growth rates between individual species varied considerably, from 0.181 d−1 [Gyrosigma peisonis (Grunow) Hustedt] to 0.861 d−1 [Navicula phyllepta (Kutzing)], while the intraspecific growth rates were only slightly influenced by most of the tested variables. In detail, individual effects were found for different substrates (mixed glass beads, mixed sands, none), nitrogen sources (nitra...