The taxonomical position of the centric diatom genus Pelagodictyon CLARKE with remarks to the generic concept of the genus Cyclostephanos

2000 ◽  
Vol 100 ◽  
pp. 51-64 ◽  
Author(s):  
Sergei I. Genkal ◽  
Keve T. Kiss
Keyword(s):  
Centric Diatom ◽  
Generic Concept ◽  
Diatom Genus ◽  
Taxonomical Position

Taxonomy, phylogeny, and paleoecology of Eoseira wilsonii gen. et sp. nov., a Middle Eocene diatom (Bacillariophyceae: Aulacoseiraceae) from lake sediments at Horsefly, British Columbia, Canada

2005 ◽  
Vol 42 (2) ◽  
pp. 243-257 ◽  
Author(s):  
Alexander P Wolfe ◽  
Mark B Edlund
Keyword(s):  
British Columbia ◽  
Middle Eocene ◽  
Life Strategy ◽  
Centric Diatom ◽  
Evolutionary Trajectory ◽  
The Family ◽  
Freshwater Diatoms ◽  
Marine Realm ◽  
Diatom Genus ◽  
Early Cenozoic

A new centric diatom genus is described from laminated freshwater sediments of Middle Eocene age near Horsefly, British Columbia, Canada. This diatom, Eoseira wilsonii gen. et sp. nov., grew in filaments that constitute dense monospecific sub-horizons within the white couplets that represent summer deposition in the varved sequence. Although Eoseira clearly belongs within the Family Aulacoseiraceae, several features distinguish its valve structure from Aulacoseira. Gigantism of spines and the lack of geometric relationships between spine position and mantle areolae are the most conspicuous features of the genus. Eoseira is among the oldest freshwater diatoms known and one of relatively few extinct freshwater genera. In addition to serving as a potential biostratigraphic marker, Eoseira is a cornerstone to undertanding the evolutionary trajectory of the Aulacoseiraceae, likely the oldest family of freshwater diatoms. As such, it refines our understanding of early radiations from the marine realm in western North America. Furthermore, paleoecological inferences based on Eoseira life strategy pertain directly to limnological conditions during early Cenozoic hot-house conditions.

Ferocia gen. nov., a new centric diatom genus (Bacillariophyceae) from the sub-Antarctic region

Phytotaxa ◽  
2017 ◽  
Vol 332 (1) ◽  
pp. 22 ◽  
Author(s):  
BART VAN DE VIJVER ◽  
BARBORA CHATTOVÁ ◽  
MARC LEBOUVIER ◽  
VÁCLAV HOUK
Keyword(s):  
Indian Ocean ◽  
New Genus ◽  
Southern Indian Ocean ◽  
Centric Diatom ◽  
Volcanic Island ◽  
Antarctic Region ◽  
Diatom Flora ◽  
Large Complex ◽  
Mantle Edge ◽  
Diatom Genus

A new centric diatom genus, Ferocia Van de Vijver & Houk gen. nov. is described based on Melosira setosa Greville. Several samples collected in lava tunnels on Ile Amsterdam, a small isolated, volcanic island in the southern Indian Ocean where the latter taxon dominated the diatom flora, were investigated. The new genus is characterized by having heavily silicified, spherical frustules, connected into long chains by large, complex linking spines. Valves are dome-shaped with a high mantle with rounded to irregularly shaped areolae. Numerous small rimoportulae forming a marginal ring are present near the mantle edge. The cingulum is composed of a large number of narrow, open copulae. A second species, Ferocia ninae Van de Vijver & Houk sp. nov., is described from the nearby Crozet archipelago. Besides the typical features of the genus Ferocia, the rimoportulae in F. ninae are almost equidistant, the valves have a relatively low valve height and the spines are relatively small.         Both F. ninae and F. setosa were found in shaded lava tunnels with a sparse moss vegetation. The two species are illustrated and discussed based on detailed LM and SEM observations.

scholarly journals Validation of the centric diatom genus nameCyclostephanos

1987 ◽  
Vol 22 (4) ◽  
pp. 345-347 ◽  
Author(s):  
Edward Theriot ◽  
Hannelore Håkansson ◽  
J. Patrick Kociolek ◽  
Frank E. Round ◽  
Eugene F. Stoermer
Keyword(s):  
Centric Diatom ◽  
Diatom Genus

scholarly journals Pantocsekiella, a new centric diatom genus based on morphological and genetic studies

Fottea ◽  
2016 ◽  
Vol 16 (1) ◽  
pp. 56-78 ◽  
Author(s):  
Eva Acs ◽  
Eszter Ari ◽  
Monika Duleba ◽  
Mirko Dressler ◽  
Sergei I. Genkal ◽  
...  
Keyword(s):  
Centric Diatom ◽  
Genetic Studies ◽  
Diatom Genus

A Politics of Intensity: Some Aspects of Acceleration in Simondon and Deleuze

2017 ◽  
Vol 11 (4) ◽  
pp. 498-517
Author(s):  
Yuk Hui ◽  
Louis Morelle
Keyword(s):  
Conceptual Framework ◽  
The Other ◽  
Generic Concept ◽  
Philosophical Thought ◽  
Ontological Ground ◽  
Shed Light

This article aims to clarify the question of speed and intensity in the thoughts of Simondon and Deleuze, in order to shed light on the recent debates regarding accelerationism and its politics. Instead of starting with speed, we propose to look into the notion of intensity and how it serves as a new ontological ground in Simondon's and Deleuze's philosophy and politics. Simondon mobilises the concept of intensity to criticise hylomorphism and substantialism; Deleuze, taking up Simondon's conceptual framework, repurposes it for his ontology of difference, elevating intensity to the rank of generic concept of being, thus bypassing notions of negativity and individuals as base, in favour of the productive and universal character of difference. In Deleuze, the correlation between intensity and speed is fraught with ambiguities, with each term threatening to subsume the other; this rampant tension becomes explicitly antagonistic when taken up by the diverse strands of contemporary accelerationism, resulting in two extreme cases in the posthuman discourse: either a pure becoming, achieved through destruction, or through abstraction that does away with intensity altogether; or an intensity without movement or speed, that remains a pure jouissance. Both cases appear to stumble over the problem of individuation, if not disindividuation. Hence, we wish to raise the following question: in what way can one think of an accelerationist politics with intensity, or an intensive politics without the fetishisation of speed? We consider this question central to the interrogation of the limits of acceleration and posthuman discourse, thus requiring a new philosophical thought on intensity and speed.

Motility in the Diatom Genus Eunotia Ehrenb.

2021 ◽  
pp. 185-209
Author(s):  
Paula C. Furey
Keyword(s):  
Diatom Genus
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