Four new Luticola taxa (Bacillariophyta) from Maritime Antarctica 

Phytotaxa ◽  
2014 ◽  
Vol 170 (3) ◽  
pp. 155 ◽  
Author(s):  
RALITSA ZIDAROVA ◽  
ZLATKO LEVKOV ◽  
BART VAN DE VIJVER

The paper describes four new Luticola taxa from the South Shetland Archipelago, Antarctica:  Luticola neglecta sp. nov., L. bogaertsiana sp. nov., L. contii sp. nov. and L. olegsakharovii sp. nov. All new taxa are studied using both light and scanning electron microscopy and compared to other morphologically similar species from (sub-)Antarctica and elsewhere in the world. Data on their ecology and biogeography are added. 

Phytotaxa ◽  
2013 ◽  
Vol 126 (1) ◽  
pp. 1 ◽  
Author(s):  
CHIARA PENNESI ◽  
MICHEL POULIN ◽  
FRIEDEL HINZ ◽  
TIZIANA ROMAGNOLI ◽  
MARIO DE STEFANO ◽  
...  

In this study, seven Mastogloia species belonging of the section Ellipticae are morphologically described through scanning electron microscopy, including two new taxa M. matthaei and M. stellae. They were collected as epiphytes on seagrasses from several tropical (Indonesia), subtropical (Egypt, Greece, Republic of Malta, Turkey) and temperate (Slovenia, Italy) regions of the world. All these species show typical characters of the Hustedt’s section Ellipticae: elliptical valve outline, a flat valve surface and rounded apices. Moreover, this study provides novel information on the frustule ultrastructure and gives update of their current geographical distribution. Some nomenclatural inconsistencies have been resolved with the typification of M. ovulum and the related species, M. emarginata, from the original Miang Besar material in the Hustedt collection.


Phytotaxa ◽  
2018 ◽  
Vol 358 (3) ◽  
pp. 265 ◽  
Author(s):  
EDUARDO A. TUSSET ◽  
PRISCILA I. TREMARIN ◽  
THELMA A.V. LUDWIG

The morphology of three Stauroneis species from midwestern karstic Brazilian formations was illustrated under light and electron microscopy. Two new Stauroneis are described and compared with similar species in the genus. Stauroneis cavalcantei Tremarin, Tusset & T. Ludwig is characterized by lanceolate valves with subtly protracted apices, and S. karstica Tusset, Tremarin & T. Ludwig by rhombic-lanceolate valves with attenuate to acutely-rounded apices, reduced pseudosepta, bow-tie-shaped stauros, and areolae depressed along prominent longitudinal-oriented apical ribs. Stauroneis alabamae is a scarcely known species and unprecedented scanning electron microscopy illustrations are provided.


2019 ◽  
Vol 152 (2) ◽  
pp. 340-350
Author(s):  
Carlos E. Wetzel ◽  
Ingrid Jüttner ◽  
Smriti Gurung ◽  
Luc Ector

Background and aims – Two unknown benthic diatom species belonging to the genus Achnanthidium Kütz., and found in French and Nepalese freshwater habitats, were investigated. Both species are here described as new and compared with the original material of Achnanthes minutissima var. macrocephala Hust. [≡ Achnanthidium macrocephalum (Hust.) Round & Bukht.] from Indonesia. Methods – The morphology of three small and capitate Achnanthidium species was investigated using light microscopy (LM) and scanning electron microscopy (SEM). Key results – Achnanthidium coxianum sp. nov. (from the Himalaya) belongs to the group of species with hooked terminal raphe endings, while Achnanthidium peetersianum sp. nov. (from France) has variable terminal raphe endings which are usually slightly bent. Achnanthidium macrocephalum is a much rarer species and illustrations concerning its identity in the literature do not conform to the type studied here. Conclusions – The three species are similar in LM but clearly distinct in SEM. The shape of the areolae and terminal raphe endings separate the species. Achnanthidium macrocephalum has often been misidentified in studies from many areas of the world. It is similar to the new species in valve outline and in its small dimensions.


Phytotaxa ◽  
2021 ◽  
Vol 494 (2) ◽  
pp. 208-218
Author(s):  
DMITRY CHUDAEV ◽  
INGRID JÜTTNER ◽  
ZLATKO LEVKOV

This is the first detailed taxonomic study of the genus Navicula in the Krasnodar Territory of the Caucasus region, Russia. During the study of the genus in waterbodies of the Adegoy River valley 15 taxa were recorded. Two species, N. adegoyensis sp. nov. and N. pseudocryptofallax sp. nov., are described as new to science. Their morphology is studied by light and scanning electron microscopy, and comparisons with morphologically similar species are provided. The use of the name N. avenacea for N. lanceolata sensu auct. is discussed. Navicula diversity was higher in the Adegoy River than in pools elsewhere in the river valley.


Phytotaxa ◽  
2021 ◽  
Vol 508 (2) ◽  
Author(s):  
DMITRY CHUDAEV ◽  
INGRID JÜTTNER ◽  
BART VAN DE VIJVER

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.


Phytotaxa ◽  
2018 ◽  
Vol 349 (2) ◽  
pp. 115 ◽  
Author(s):  
CATHERINE RIAUX-GOBIN ◽  
ANDRZEJ WITKOWSKI ◽  
RICHARD W. JORDAN ◽  
VALERIANO PARRAVICINI ◽  
SERGE PLANES

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.


Phytotaxa ◽  
2014 ◽  
Vol 184 (4) ◽  
pp. 208 ◽  
Author(s):  
Priscila Izabel Tremarin ◽  
Thelma Ludwig ◽  
Lezilda Torgan

Examination of samples from different aquatic environments from Brazil revealed the presence of a new Aulacoseira species. Aulacoseira veraluciae Tremarin, Torgan & T. Ludwig is described and illustrated with light and scanning electron microscopy, and its morphology compared with that of similar species, such as A. muzzanensis (Meister) Krammer, A. granulata (Ehrenberg) Simonsen and A. agassizii (Ostenfeld) Simonsen. The new species is characterized mainly by the straight pervalvar rows of areolae, morphology of the linking spines, shape and position of the rimoportulae on the valve mantle, deepness and thickness of the ringleiste.


Phytotaxa ◽  
2017 ◽  
Vol 308 (2) ◽  
pp. 249 ◽  
Author(s):  
ZHONGYAN ZHANG ◽  
PATRICK RIOUAL ◽  
YUMEI PENG ◽  
XIAOPING YANG ◽  
ZHANGDONG JIN ◽  
...  

This paper describes a new Cymbella species from an alpine lake in the Pamir Mountains, NW China, with the aid of light and scanning electron microscopy and morphometric analyses. The morphology of the new species, named Cymbella pamirensis, is discussed and compared to similar species. The main morphometric features distinguishing Cymbella pamirensis from similar species of Cymbella are the outline and size of the valves. Cymbella pamirensis has been observed in surface sediment and core samples from Lake Sate Baile Dikuli, an alkaline, mesotrophic lake of the Pamir Mountains.


Phytotaxa ◽  
2015 ◽  
Vol 236 (3) ◽  
pp. 257 ◽  
Author(s):  
Wei Zhang ◽  
Yan Ling Li ◽  
J Patrick Kociolek ◽  
Rui Lei Zhang ◽  
Li Qing Wang

During a survey of freshwater diatoms from streams in the west region of the Tianmu Mountains, Zhejiang Province, China, a new Oricymba species, Oricymba tianmuensis sp. nov. has been recorded. A detailed morphology description of O. tianmuensis is presented, based on light and scanning electron microscopy. Oricymba tianmuensis sp. nov. is characterized by a ridge along the valve face typical of the genus, as well as a linear-lanceolate, symmetrical or slightly dorsiventral outline with a gibbous central portion gradually tapering or nearly paralleling towards the bluntly cuneate poles, a distinct rhombic-lanceolate asymmetric central area with a distinct stigma on the ventral side of the central nodule, a slightly lateral raphe with widened proximal endings and strongly deflected distal endings, and weakly radiate striae. Morphological features of the taxon are compared with similar species, and the biogeography of the genus is summarized.


Phytotaxa ◽  
2014 ◽  
Vol 186 (2) ◽  
pp. 61 ◽  
Author(s):  
YUMEI PENG

A new medium-sized species of Hippodonta (Bacillariophyceae) is described from Lake Qinghai, China. The morphology and ultrastructure of Hippodonta qinghainensis sp. nov. are described using light and scanning electron microscopy. This new species is compared with similar species of Hippodonta using conventional and geometric morphometric analyses. Hippodonta qinghainensis can be separated from the other species of Hippodonta by a unique combination of characters that include an elliptic-lanceolate to rhombic-lanceolate valve shape, non protracted apices, the absence of fascia, relatively coarse, uniseriate striae and the presence of two rows of lineolae around the valves apices.


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