Diatomella colonialis, a new diatom species (Bacillariophyta) from the sub-Antarctic Region

Phytotaxa ◽  
2017 ◽  
Vol 306 (4) ◽  
pp. 281 ◽  
Author(s):  
BART VAN DE VIJVER ◽  
RENÉ LE COHU

During a survey of the freshwater diatom flora of the sub-Antarctic Kerguelen archipelago in the southern Indian Ocean, an unknown Diatomella taxon was observed forming long colonies using linking spines. Detailed morphological analysis based on light and scanning electron microscopical observations and comparison with all known Diatomella taxa worldwide justified the description of this unknown taxon as a new species: Diatomella colonialis sp. nov. The new taxon is characterized by the presence of marginal linking spines, the reduction of its raphe structure leaving only two short raphe slits near the apices, a very large axial area occupying almost the entire valve face and very short alveolate striae composed of paired areolae. The presence of these alveolate striae and the girdle structure with its typical scalariform valvocopula place this taxon in the genus Diatomella.         The new species is described and compared with other Diatomella taxa. Notes on its distribution and ecology are added. 

Phytotaxa ◽  
2018 ◽  
Vol 333 (1) ◽  
pp. 108 ◽  
Author(s):  
BART VAN DE VIJVER ◽  
STEVEN DESSEIN

During a survey of the freshwater diatom flora of the sub-Antarctic region (Iles Kerguelen and Iles Crozet) in the southern Indian Ocean, an unknown Cyclotella taxon was observed that was formerly identified as the presumed cosmopolitan C. meneghinana. Detailed morphological analysis based on light and scanning electron microscopical observations and comparison with several similar Cyclotella taxa worldwide justified the description of this unknown taxon as a new species: Cyclotella deceusteriana sp. nov. The new taxon is characterized by the presence of marginal fultoportulae on every costa, hyaline furrows between the raised marginal parts on which the striae are located, 2, occasionally 1, 3 or 4 central fultoportulae and an entirely flat, smooth, relatively small central area. The new species is described and compared with other Cyclotella taxa. Notes on its distribution and ecology are added.


Phytotaxa ◽  
2020 ◽  
Vol 429 (1) ◽  
pp. 57-64
Author(s):  
BART VAN DE VIJVER ◽  
PETRA BALLINGS ◽  
CHARLOTTE GOEYERS

During a survey of the freshwater diatom flora of the sub-Antarctic Campbell Island, located in the southern Pacific Ocean, an unknown freshwater diatom was observed forming long colonies using linking spines. Detailed morphological analysis based on light and scanning electron microscopical observations and comparison with all known Frankophila taxa worldwide justified the description of this unknown taxon as a new species within the genus Frankophila: Frankophila dalevittii Van de Vijver & Goeyers sp. nov. The new taxon is characterized by the presence of well-developed linking spines, the absence of external raphe slits and the presence of internal raphe slits, biseriate striae composed of relatively large areolae and a large axial area. Despite the absence of the external raphe slits, the species is best placed within the genus Frankophila. The new species is described and illustrated and compared with all other Frankophila taxa.


2019 ◽  
Vol 152 (2) ◽  
pp. 385-391
Author(s):  
Valeria Casa ◽  
Gabriela Mataloni ◽  
Bart Van de Vijver

Background and aims – A few years ago, a new survey started of the freshwater diatom flora from peatbogs of Tierra del Fuego (southern Argentina). During this survey, an unknown fragilarioid diatom belonging to the genus Distrionella that could not be identified using the currently available literature was discovered. Methods – Using both Light Microscopical and Scanning Electron Microscopical techniques, the morphology of the unknown Distrionella species has been analysed. The new taxon is properly described, illustrated and compared with all other possible similar Distrionella taxa, known worldwide. Key results – Distrionella coxiana possesses a unique combination of morphological features that excludes conspecificity with all other members of the genus; it is characterized in having narrow, linear valves with small, capitate apices. Transapical ribs, a typical feature of the genus Distrionella, are only weakly developed. One rimoportula is observed close to the apices. Both apices have well-developed apical porefields. The girdle bands bear one complete row of poroids often accompanied by a second, incomplete row of small poroids. Notes on the occurrence and ecology of the new taxon are added.


Phytotaxa ◽  
2015 ◽  
Vol 205 (3) ◽  
pp. 197
Author(s):  
Ian Bishop ◽  
Sarah Spaulding

Here we describe a new freshwater diatom species from the Cascade Mountain Range in Washington State, including observations of living cells and chloroplast structure. The species represents the fourth known extant species within the genus, as most species of Tetracyclus Ralfs are extinct. The new species can be distinguished from other Tetracyclus species and Diatoma mesodon Kützing by its lanceolate-elliptical shape, apiculate ends, small size, rimoportula placement, and distinct septa pattern. The distribution of the new taxon is currently catchments within the Mt. Baker-Snoqualmie National Forest and Mount Rainier National Park, and is found in greatest abundance in aerophilous, moss and liverwort habitats in first- and second-order streams.


Zootaxa ◽  
2013 ◽  
Vol 3626 (3) ◽  
pp. 345-355 ◽  
Author(s):  
ADRIAN KIN ◽  
BŁAŻEJ BŁAŻEJOWSKI

This study presents a detailed morphological analysis of a new species belonging to the blind trilobite Trimerocephalus McCoy, 1849, T. chopini n. sp., based on exceptionally well preserved articulated specimens from the Late Devonian (Early Famennian) of the Holy Cross Mountains in central Poland. The occurrence of this taxon in Kowala Quarry near Kielce has been reported previously, with specimens often found in single-file queues representing migratory behaviour that was followed by a mass mortality event that preserved these assemblages. The new taxon is compared with other species of Trimerocephalus and is interpreted as being most closely related to a clade consisting of T. caecus, T. lelievrei, T. mimbi, T. shotoriensis and T. tardispinosus.


2019 ◽  
Vol 152 (3) ◽  
pp. 539-545
Author(s):  
Bart Van de Vijver ◽  
Luc Ector

Background and aims – During a survey of the soil diatom flora of the sub-Antarctic islands in the southern Indian Ocean, an unknown small-celled naviculoid taxon was discovered living in small cracks in cliffs bordering the ocean. The taxon showed a set of morphological features only found in the genus Microcostatus. However, the unknown taxon could not be identified using the currently available literature. Methods – Using both light microscopical and scanning electron microscopical techniques, the morphology of the unknown Microcostatus taxon was documented. The new taxon is described, illustrated and compared with all other similar Microcostatus taxa worldwide. Key results – Microcostatus elisabethianus possesses a unique combination of morphological features that excludes conspecificity with all other members of the genus. It is characterized by a lanceolate valve outline with protracted, elongate apices, a very large, porous conopeum reaching the valve margins and uniseriate striae composed of only one macroareola and mantle areolae restricted to the valve apices. The morphological features of the genus Microcostatus are evaluated and discussed. Notes on the occurrence and ecology of the new taxon are added.


Author(s):  
Marie L Verheye ◽  
Cédric D’Udekem D’Acoz

Abstract Among Antarctic amphipods of the genus Eusirus, a highly distinctive clade of giant species is characterized by a dorsal, blade-shaped tooth on pereionites 5–7 and pleonites 1–3. This lineage, herein named ‘crested Eusirus’, includes two potential species complexes, the Eusirus perdentatus and Eusirus giganteus complexes, in addition to the more distinctive Eusirus propeperdentatus. Molecular phylogenies and statistical parsimony networks (COI, CytB and ITS2) of crested Eusirus are herein reconstructed. This study aims to formally revise species diversity within crested Eusirus by applying several species delimitation methods (Bayesian implementation of the Poisson tree processes model, general mixed Yule coalescent, multi-rate Poisson tree processes and automatic barcode gap discovery) on the resulting phylogenies. In addition, results from the DNA-based methods are benchmarked against a detailed morphological analysis of all available specimens of the E. perdentatus complex. Our results indicate that species diversity of crested Eusirus is underestimated. Overall, DNA-based methods suggest that the E. perdentatus complex is composed of three putative species and that the E. giganteus complex includes four or five putative species. The morphological analysis of available specimens from the E. perdentatus complex corroborates molecular results by identifying two differentiable species, the genuine E. perdentatus and a new species, herein described as Eusirus pontomedon sp. nov.


2021 ◽  
pp. 1-13
Author(s):  
Rainer R. Schoch ◽  
Gabriela Sobral

Abstract The late Paleozoic temnospondyl Sclerocephalus formed an aquatic top predator in various central European lakes of the late Carboniferous and early Permian. Despite hundreds of specimens spanning a wide range of sizes, knowledge of the endocranium (braincase and palatoquadrate) remained very insufficient in Sclerocephalus and other stereospondylomorphs because even large skulls had unossified endocrania. A new specimen from a stratigraphically ancient deposit at St. Wendel in southwestern Germany is recognized as representing a new taxon, S. concordiae new species, and reveals a completely ossified endocranium. The sphenethmoid was completely ossified from the basisphenoid to the anterior ethmoid region, co-ossified with the parasphenoid, and the basipterygoid joint was fully established. The pterygoid bears a slender, S-shaped epipterygoid, which formed a robust pillar lateral to the braincase. The massive stapes was firmly sutured to the parasphenoid. In the temnospondyl endocranium, character evolution involved various changes in the epipterygoid region, which evolved distinct morphologies in each of the major clades. UUID: http://zoobank.org/5e6d2078-eacf-4467-84cf-a12efcae7c0b


PLoS ONE ◽  
2016 ◽  
Vol 11 (3) ◽  
pp. e0149726 ◽  
Author(s):  
Ali Bagheri ◽  
Ali Asghar Maassoumi ◽  
Mohammad Reza Rahiminejad ◽  
Frank R. Blattner

2006 ◽  
Vol 25 (2) ◽  
pp. 141-151 ◽  
Author(s):  
Jeremy R. Young ◽  
Harald Andruleit

Abstract. A very distinctive new deep-photic coccolithophore is described from the NE Indian Ocean. The new species is trimorphic with: 200–300 body coccoliths bearing low spines attached by narrow stems to a basal narrow-rimmed placolith structure; up to 18 circum-flagellar coccoliths with tall sail-like spines; and up to 22 coccoliths with moderately elevated spines occurring both around the circum-flagellar coccoliths and antapically. These features make the coccolithophore unique and require placement in a new species and genus. The basal structure, however, shows similarities to a recently recognized group of narrow-rimmed placoliths. Hence, the new coccolithophore provides some support for this grouping as a significant addition to our understanding of coccolithophore biodiversity, and potentially an explanation for a set of anomalous molecular genetic results. In addition the new taxon provides further evidence that the deep-photic coccolithophore community is more diverse than has been assumed.


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