Staurosirella andino-patagonica sp. nov. (Bacillariophyta) from lake sediments in Patagonia, Argentina

Phytotaxa ◽  
2019 ◽  
Vol 402 (3) ◽  
pp. 131 ◽  
Author(s):  
JOSÉ MARÍA GUERRERO ◽  
MARÍA LUJÁN GARCÍA ◽  
EDUARDO A. MORALES
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Lake Sediments ◽  
Surface Sediments ◽  
Geographic Area ◽  
New Taxon ◽  
Diatom Flora ◽  
The Andes ◽  
Distinct Morphology ◽  
Scanning Electron

Staurosirella andino-patagonica, a new araphid diatom found in Holocene and recent surface sediments from lakes located in the Andes and adjacent steppe of Patagonia (Argentina), is described on the basis of light and scanning electron microscopy observations and comparison with related taxa. Although the elliptic valve outline of the new taxon resembles the smaller specimens of several Staurosirella species, ultrastructural features such as the presence of two spines on each virga and their distinct morphology -serrated with thickenings at the base- make Staurosirella andino-patagonica unique within the genus. Our study contributes to the knowledge of the Patagonian araphid diatom flora, a rather unexplored geographic area, and so we assume that, as additional areas are studied in detail, they will likely continue to yield new taxa.

Fragilaria irregularis sp. nov. a new araphid species (Fragilariaceae, Bacillariophyta) from the River Adegoy, Krasnodar Territory, Russia

Phytotaxa ◽  
2021 ◽  
Vol 508 (2) ◽  
Author(s):  
DMITRY CHUDAEV ◽  
INGRID JÜTTNER ◽  
BART VAN DE VIJVER
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
New Species ◽  
Similar Species ◽  
New Taxon ◽  
Weakly Convex ◽  
Diatom Flora ◽  
A New Species ◽  
Scanning Electron

During a survey of the diatom flora of the Adegoy River (Krasnodar Territory, Russia), an unknown Fragilaria species (Bacillariophyta) was found that could not be identified using the currently available literature and here we describe it as a new species. The morphology of Fragilaria irregularis sp. nov. was studied using light and scanning electron microscopy and compared to similar species including Fragilaria deformis, F. rinoi, F. septentrionalis and Fragilariforma bicapitata. It differed from these taxa in several characters. Most observed valves showed an irregular striation pattern, a feature not observed in other species. Other important differences include valve outline (linear with parallel margins) and stria density (7–14 in 10 µm, lower compared to all other species). The new taxon has a linear valve outline with parallel to weakly convex margins, subcapitate apices and a very irregular, coarse striation pattern.

Luticola puchalskiana, a new small terrestrial Luticola species (Bacillariophyceae) from the Maritime Antarctic Region

Phytotaxa ◽  
2020 ◽  
Vol 450 (1) ◽  
pp. 85-94
Author(s):  
NATALIA KOCHMAN-KĘDZIORA ◽  
RALITSA ZIDAROVA ◽  
TERESA NOGA ◽  
MARIA OLECH ◽  
BART VAN DE VIJVER
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Morphological Analysis ◽  
New Taxon ◽  
Maritime Antarctic ◽  
Antarctic Region ◽  
Diatom Flora ◽  
Terrestrial Habitats ◽  
Two Populations ◽  
Scanning Electron

During a survey of the terrestrial diatom flora of the Maritime Antarctic Region, an unknown Luticola taxon that could not be identified using the currently available literature was observed on two islands of the South Shetland Archipelago. After a detailed morphological analysis and comparison, the unknown taxon is described as Luticola puchalskiana sp. nov. The new species can be separated from other Luticola species based on its valve dimensions, stria density and the shape of both central and terminal raphe endings. Two populations of the new taxon were observed in samples collected from terrestrial habitats. The morphology of Luticola puchalskiana is elaborately described and illustrated using both light and scanning electron microscopy observations. A comparison is made with a large number of other morphologically similar Luticola species from the entire (sub)Antarctic Region.

Achnanthidium petuniabuktianum sp. nov. (Achnanthidiaceae, Bacillariophyta), a new representative of the A. pyrenaicum group from Spitsbergen (Svalbard Archipelago, High Arctic)

Phytotaxa ◽  
2015 ◽  
Vol 226 (1) ◽  
pp. 63 ◽  
Author(s):  
Eveline Pinseel ◽  
Bart Van de Vijver ◽  
Katerina Kopalova
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Arctic Region ◽  
High Arctic ◽  
New Taxon ◽  
Freshwater Lakes ◽  
Svalbard Archipelago ◽  
Diatom Flora ◽  
Littoral Zones ◽  
Scanning Electron

During a survey of the freshwater littoral diatom flora from lakes and ponds in the region of Petuniabukta on Spitsbergen (Svalbard Archipelago, High Arctic region), a new Achnanthidium species, A. petuniabuktianum sp. nov., has been recorded. Achnanthidium petuniabuktianum is a new representative of the A. pyrenaicum group as evidenced by its curved distal raphe fissures. The present paper describes in detail the morphology of A. petuniabuktianum based on light and scanning electron microscopy. The new taxon is characterized in having linear valves with parallel margins and broadly rounded, never protracted apices and a characteristic—in light microscopy hardly discernible—striation pattern consisting of very short striae composed of one or two small, always slit-like areolae. Based on current results, Achnanthidium petuniabuktianum is a benthic taxon occurring in epilithic and epiphytic habitats in the littoral zones of freshwater lakes and ponds.

Stauroneis fuegiana, a new Stauroneis species (Bacillariophyta) from Tierra del Fuego, southern Argentina

Phytotaxa ◽  
2017 ◽  
Vol 311 (1) ◽  
pp. 85
Author(s):  
VALERIA CASA ◽  
GABRIELA MATALONI ◽  
BART VAN DE VIJVER
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Central Area ◽  
Taxonomic Position ◽  
Tierra Del Fuego ◽  
Peat Bog ◽  
New Taxon ◽  
Diatom Flora ◽  
Scanning Electron

During a survey of the freshwater aquatic diatom flora of two peat bog areas in Tierra del Fuego, southern Argentina, a new taxon belonging to the genus Stauroneis that could not be identified was observed. Based on detailed light and scanning electron microscopy observations and comparison with similar larger-celled Stauroneis species worldwide, the taxon is described as new: Stauroneis fuegiana Casa & Van de Vijver sp. nov. Stauroneis fuegiana can be distinguished based on the slightly raised marginal crest, the typical broadly lanceolate valve outline with subrostrate apices, the almost rectangular central area and its valve dimensions.Comments are made on its taxonomic position and how the new taxon can be distinguished from other larger-celled Stauroneis species. Brief notes on the ecology and distribution are added.

Encyonema oblonga (Bacillariophyta, Cymbellaceae), a new species from Shanxi Province, China

Phytotaxa ◽  
2021 ◽  
Vol 480 (3) ◽  
pp. 284-290
Author(s):  
QI LIU ◽  
JIAJIA LI ◽  
QUANXI WANG ◽  
JOHN PATRICK KOCIOLEK Patrick Kociolek ◽  
Shulian Xie
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
New Species ◽  
Shanxi Province ◽  
Diatom Flora ◽  
A New Species ◽  
Scanning Electron ◽  
Freshwater Diatom

A new species, Encyonema oblonga Liu & Xie, is collected during a survey of the freshwater diatom flora of Manghe River, Shanxi, China. The valves of this new species are oblong with rounded apices and have the features typical of Encyonema, including complex areolae. We compare the new species with the most similar taxa, E. leei, E. leei var. sinensis and E. appalachianum and consider that  E. leei var. sinensis is the valid name.  The morphology of E. oblonga is documented with light and scanning electron microscopy.

Direct Determination of Apatite in Lake Sediments

1980 ◽  
Vol 37 (4) ◽  
pp. 640-646 ◽  
Author(s):  
R. P. Reid ◽  
C. H. Pharo ◽  
W. C. Barnes
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Lake Sediments ◽  
Trophic State ◽  
Inorganic Phosphorus ◽  
Source Rocks ◽  
Emission Spectrometry ◽  
Phosphorus Load ◽  
Lake Trophic State ◽  
Scanning Electron

Apatite is a common accessory mineral in the source rocks for the glacial debris supplying sediments to many Canadian lakes. A method has been developed which uses scanning electron microscopy and energy dispersive X-ray emission spectrometry for direct identification of apatite. This method has been used to examine the apatite content of various size fractions in Kamloops Lake sediments. Apatite concentrations obtained by this direct examination correlate well (r > 0.999) with apatite concentrations determined by chemical analyses and indicate that, in addition to comprising as much as 70% of the total phosphorus load, apatite may comprise as much as one-third of the "dissolved" (< 0.45 μm) inorganic phosphorus load. Consequently the use of classical (e.g. Vollenweider 1968; Vollenweider and Dillon 1974) methods of estimating lake trophic state from inorganic phosphorus concentrations in lake water must be done with care, recognizing that the bulk of inorganic phosphorus in lakes deriving sediment from glaciated igneous or metamorphic terrains may be in the form of apatite.Key words: apatite, lake, trophic state, phosphorus load, scanning electron microscopy

Cocconeis kurakakea, a new diatom species from Nukutavake (Tuamotu Archipelago, South Pacific): description and comparison with C. diruptoides and C. pseudodiruptoides

Phytotaxa ◽  
2018 ◽  
Vol 349 (2) ◽  
pp. 115 ◽  
Author(s):  
CATHERINE RIAUX-GOBIN ◽  
ANDRZEJ WITKOWSKI ◽  
RICHARD W. JORDAN ◽  
VALERIANO PARRAVICINI ◽  
SERGE PLANES
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
South Pacific ◽  
Benthic Diatom ◽  
New Taxon ◽  
Diatom Species ◽  
The South ◽  
Standard Methods ◽  
Tuamotu Archipelago ◽  
Scanning Electron

During the ‘Tara Pacific 2016–2018 Expedition’, marine benthic diatom samples were collected from several Tuamotu atolls in the South Pacific. Preparation and examination of these samples were conducted following standard methods including light and scanning electron microscopy. A small-celled taxon from the genus Cocconeis Ehrenb. (Bacillariophyceae) is described from the Nukutavake reef, and compared to several other taxa for which the definition is not always clear (e.g., Cocconeis diruptoides Hust. and Cocconeis pseudodiruptoides Foged). The new taxon is present only on one of the investigated Tuamotu atolls, possibly indicating local endemism.

Two new centric diatoms (Bacillariophyta) from the sub-Antarctic region

Phytotaxa ◽  
2019 ◽  
Vol 394 (1) ◽  
pp. 50 ◽  
Author(s):  
BART VAN DE VIJVER ◽  
VÁCLAV HOUK
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Central Area ◽  
Soil Samples ◽  
Antarctic Region ◽  
Diatom Flora ◽  
Main Island ◽  
Centric Diatoms ◽  
Heard Island ◽  
Scanning Electron

During a survey of the limno-terrestrial diatom flora of the sub-Antarctic region, two unknown melosiroid diatom taxa were observed in several shaded, damp cave (moss and soil) samples from Heard Island and Ile de la Possession, the main island of the Crozet Archipelago. Comparison with already known species from the genus Melosira and the recently described genera Arcanodiscus, Angusticopula and Ferocia, resulted in the description of both new taxa based on detailed light and scanning electron microscopy. A first species was described as Ferocia subantarctica sp. nov. and can be distinguished based on its numerous, narrow girdle bands, relatively weakly domed valves, a limited number of well-developed spines and a rather large, hyaline central area. The second species, Arcanodiscus desmetianus Van de Vijver sp. nov., can be recognized based on its solitary frustules, a series of parallel ridges surrounding the mantle and a hyaline central area that is only less than 50% of the total valve diameter. Both taxa are morphologically and ecologically characterized and compared with all known melosiroid taxa worldwide.

scholarly journals Joermungandr bolti , an exceptionally preserved ‘microsaur’ from the Mazon Creek Lagerstätte reveals patterns of integumentary evolution in Recumbirostra

2021 ◽  
Vol 8 (7) ◽  
pp. 210319
Author(s):  
Arjan Mann ◽  
Ami S. Calthorpe ◽  
Hillary C. Maddin
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Phylogenetic Analysis ◽  
New Taxon ◽  
Phylogenetic Methods ◽  
Mazon Creek ◽  
Single Part ◽  
Scanning Electron

The Carboniferous Pennsylvanian-aged (309–307 Ma) Mazon Creek Lagerstätte produces some of the earliest fossils of major Palaeozoic tetrapod lineages. Recently, several new tetrapod specimens collected from Mazon Creek have come to light, including the earliest fossorially adapted recumbirostrans. Here, we describe a new long-bodied recumbirostran, Joermungandr bolti gen. et sp. nov., known from a single part and counterpart concretion bearing a virtually complete skeleton. Uniquely, Joermungandr preserves a full suite of dorsal, flank and ventral dermal scales, together with a series of thinned and reduced gastralia. Investigation of these scales using scanning electron microscopy reveals ultrastructural ridge and pit morphologies, revealing complexities comparable to the scale ultrastructure of extant snakes and fossorial reptiles, which have scales modified for body-based propulsion and shedding substrate. Our new taxon also represents an important early record of an elongate recumbirostran bauplan, wherein several features linked to fossoriality, including a characteristic recumbent snout, are present. We used parsimony phylogenetic methods to conduct phylogenetic analysis using the most recent recumbirostran-focused matrix. The analysis recovers Joermungandr within Recumbirostra with likely affinities to the sister clades Molgophidae and Brachystelechidae. Finally, we review integumentary patterns in Recumbirostra, noting reductions and losses of gastralia and osteoderms associated with body elongation and, thus, probably also associated with increased fossoriality.

scholarly journals An updated list of Serbian diatom flora: New recorded taxa

2018 ◽  
Vol 70 (2) ◽  
pp. 259-275 ◽  
Author(s):  
Danijela Vidakovic ◽  
Olga Jakovljevic ◽  
Dragana Predojevic ◽  
Sanja Radovanovic ◽  
Gordana Subakov-Simic ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Light Microscopy ◽  
Salt Marshes ◽  
Aquatic Ecosystems ◽  
Diatom Flora ◽  
Reliable Identification ◽  
Environmental Status ◽  
Diversity Studies ◽  
Scanning Electron

Diatoms are a widespread group of organisms with well-known ecological preferences. Knowledge of their diversity is of great importance for assessing the environmental status of different aquatic ecosystems. The present study was based on 55 different localities that included rivers, streams, channels, accumulations and salt marshes throughout Serbia. The results of this study expanded the diatom checklist by 80 taxa, including two new recorded genera (Fistulifera and Microfissurata) for Serbia. The data were obtained by combining light microscopy (LM) and scanning electron microscopy (SEM) that provided reliable identification, which is very important in diatom diversity studies.

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