New Diatom Species Research Articles

Thalassiosira sundarbana sp. nov. (Bacillariophyta), an estuarine diatom from Sundarbans mangrove ecoregion based on morphology and molecular phylogeny

SummaryA new species of diatom, Thalassiosira sundarbana, is described based on light and scanning electron microscopy along with molecular phylogeny. The specimen was collected from Chemaguri creek of the Indian part of Sundarbans mangroves, and subsequently a clonal culture was established. Thalassiosira sundarbana possess variable numbers of occluded processes, and one labiate process on the valve face. Valve margin is ribbed and areolae are fasciculated on the valve face. Two rings of strutted processes are present on valve face. Strutted processes are also scattered on the valve face apart from the presence of two rings. Valvocopula and copula have rows of pore, and pleurae are hyaline. Bayesian analyses of nuclear encoded small subunit (SSU) rDNA and plastid encoded rbcL gene confirmed that T. sundarbana is phylogenetically novel. Salinity tolerance experiment with the clonal culture of T. sundarbana showed that this isolate can grow in salinity ranging from 10–35 psu. The maximum growth rate was observed in 15 psu salinity (0.5 divisions 24 h−1). On the basis of morphological features and molecular phylogeny, this clonal isolate is considered as a new estuarine species of Thalassiosira.

Orthoseira Limnopolarensissp. nov. (Bacillariophyta), a New Diatom Species from Livingston Island (South Shetland Islands, Antarctica)

A new species of diatom, Orthoseira limnopolarensis, is described from a sediment core in Limnopolar Lake on Livingston Island, South Shetlands in the South Atlantic Ocean. The new species is distinctive in having an array of numerous (12–14) carinoportulae, a number of clearly defined rimoportulae which are described here for the first time in the genus, and a valve face surface that is covered with small, irregularly scattered spines. Linking spines are less well-developed than is generally observed in species of the genus Orthoseira. No caverns or internal undulations are present. Internal valves have not been encountered.

Marennine, promising blue pigments from a widespread Haslea diatom species complex.

In diatoms, the main photosynthetic pigments are chlorophylls a and c, fucoxanthin, diadinoxanthin and diatoxanthin. The marine pennate diatom Haslea ostrearia has long been known for producing, in addition to these generic pigments, a water-soluble blue pigment, marennine. This pigment, responsible for the greening of oysters in western France, presents different biological activities: allelopathic, antioxidant, antibacterial, antiviral, and growth-inhibiting. A method to extract and purify marennine has been developed, but its chemical structure could hitherto not be resolved. For decades, H. ostrearia was the only organism known to produce marennine, and can be found worldwide. Our knowledge about H. ostrearia-like diatom biodiversity has recently been extended with the discovery of several new species of blue diatoms, the recently described H. karadagensis, H. silbo sp. inedit. and H. provincialis sp. inedit. These blue diatoms produce different marennine-like pigments, which belong to the same chemical family and present similar biological activities. Aside from being a potential source of natural blue pigments, H. ostrearia-like diatoms thus present a commercial potential for aquaculture, cosmetics, food and health industries.

New and Interesting Diatoms (Bacillariophyta) from Blue Lake Warm Springs, Tooele County, Utah

Blue Lake Warm Springs is a system of brackish lakes and marshes in western Utah, USA with a unique diatom flora that has been previously documented. Here we reexamine select taxa in greater detail, erecting two new genera and six new species from this system, and describing two additional species not observed in prior studies of the Blue Lake flora. Naviculonema stagnora gen. nov., sp. nov. and Williamsella angusta gen. nov., sp. nov are a new naviculoid genus and new pennate diatom genus lacking a raphe, respectively. Other new species of diatoms from Blue Lake Warm Springs, representing a broad range of diatom diversity, are Cyclotella utahensis sp. nov., Ulnaria tooelensis sp. nov., Pseudostaurosira moralesii sp. nov., Envekadea vanlandinghamii sp. nov., Mastogloia variabilis sp. nov., and Lunella excentrica sp. nov. The report of Envekadea is the first of the genus from inland USA waters, and the report of Lunella is the first from the USA. In addition to describing new taxa in this study, we also closely examine two known taxa, Fallacia pseudolitoricola and Nitzschia vitrea, with scanning electron microscopy, in order to better understand their morphology and biogeography. Presence of euryhaline or salt tolerant taxa in this inland ecosystem may be due to introductions by humans, either via escaped aquaculture species or transport by recreational SCUBA diving.

Gato hyalinus gen. et sp. nov., an unusual araphid tube-dwelling diatom from Western Pacific and Caribbean islands

A new species of tube-dwelling diatom, unusual in being araphid, is described from benthic coral reef habitats in Guam, Palau, Puerto Rico and Jamaica. Gato gen. nov. is heteropolar and heterovalvar, exhibits very fine striae delimiting a narrow and irregular sternum, and possesses a series of rimmed pores on each side of the foot pole. One valve of the frustule has a rimoportula at the foot pole, but both valves possess a rimoportula at the head pole. The generitype, G. hyalinus sp. nov. forms small, branched colonies. Individual cells are oval, slightly tapered along the apical axis, 30–40 µm x 13–15 µm, with 60–70 striae in 10 µm. On the foot pole with a rimoportula the rimmed pores are connected to the sternum by diagonal striae; several additional rimmed pores interrupt transapical striae further up both valves. We compare valve structure of G. hyalinus with Florella portoricensis and F. pascuensis, which we report for the first time from the Marshall Islands, and to Licmophora spp. We find no taxa to which this genus is related, and can identify no structure potentially homologous to the series of rimmed pores among the diatoms.

New diatoms (Bacillariophyta) from western North America

Twelve new species of diatoms are described from material collected in Colorado, Montana, Oregon, Washington, and Wyoming, USA, and in Alberta and British Columbia, Canada. The new species are Cavinula davisiae, Craticula johnstoniae, Craticula sardiniana, Cymatopleura internationale, Cymbella cosleyi, Cymbopleura edlundii, Gomphonema johnsonii, Navicula supleeorum, Navicula trilatera, Neidium bobmarshallensis , Stauroneis boyntoniae , and Staurophora columbiana . Two varieties are elevated to species: Neidium fogedii (replaced synonym: N. kozlowii var. densestriata ) and Neidium undulatum (replaced synonym: N. kozlowii var. undulata ). Two species are transferred to new genera: Cymbella rainierensis to Cymbopleura and Navicula soodensis to Staurophora . An Alberta population of Neidium inconstans representing significant morphological variation and range extension for this species is also presented. Water quality preferences of these taxa run the gamut from ultraoligotrophic to hypereutrophic and fresh water to hypersaline. Thirteen of these taxa are either local or Northwest regional endemics. Four of these taxa are members of the Holarctic diatom flora or they are cosmopolitan.

Haslea karadagensis (Bacillariophyta): a second blue diatom, recorded from the Black Sea and producing a novel blue pigment

A new species of raphid pennate diatom producing a blue pigment, Haslea karadagensis Davidovich, Gastineau & Mouget, sp. nov., was recently isolated from the Crimean coast of the Black Sea (Ukraine). This organism is very similar to the well-known Haslea ostrearia, the first described ‘blue’ diatom, which produces marennine, the pigment involved in the greening of oysters. The Ukrainian diatom, H. karadagensis, differs slightly from H. ostrearia in the structure of its frustule, and the two organisms are unable to interbreed. Two molecular markers, rbcL and the ITS1–5.8S–ITS2 sequences, showed 2% and >50% differences, respectively, between the two species. UV-visible spectrophotometry and in vivo confocal micro-Raman spectroscopy were used to compare the pigment of H. karadagensis with marennine. Both pigments showed absorption bands in the UV and red regions, but the positions of the maxima differ between the pigments. Significant differences were observed by micro-Raman spectroscopy in the 1000–1700 cm−1 wavenumber range, revealing that the pigments are different molecules. Haslea karadagensis is the first example of a new ‘blue’ diatom and produces a novel blue pigment.

Livingstonia (Thalassiosirales, Bacillariophyta), a new genus of fultoportulate centric diatoms from an Atlantic coastal plain river in Florida, southeastern United States

Prasad A.K.S.K and Nienow J.A. 2011. Livingstonia (Thalassiosirales, Bacillariophyta), a new genus of fultoportulate centric diatoms from an Atlantic coastal plain river in Florida, southeastern United States. Phycologia 50: 264–280. DOI: 10.2216/09-89.1A morphological and taxonomic account of Livingstonia palatkaensis, a new genus and species of centric diatoms belonging to the order Thalassiosirales Glezer & Makarova, is provided. Descriptions are based on material collected from the St. Johns River, a major, highly colored blackwater river in the Atlantic coastal plain in the southeastern United States. Scanning electron microscopic observations clearly show that although the valve structure in Livingstonia shares broad similarities with the genera Thalassiosira and Skeletonema, the types of the two fultoportulate families Thalassiosiraceae and Skeletonemataceae, respectively, it is sufficiently dissimilar to warrant the description of a new genus. Livingstonia is characterized by the presence of compound marginal processes, each formed from the external extension of a fultoportula and a semielliptical hyaline hood or cover. The areolae have semicontinuous internal cribra. A single rimoportula is present near the valve center. No fultoportulae are found at or near the center of the valve face. Furthermore, Livingstonia lacks connecting threads of marginal fultoportulae and an external extension of the rimoportula on the valve face, a combination of features that is unusual in the genus Skeletonema. Livingstonia is also distinguished from two recently described freshwater genera in the Thalassiosiraceae from the southeastern United States, Cyclotubicoalitus and Spicaticribra, in having a rimoportula away from the margin but close to the center of the valve and in other key characteristics. A note on another freshwater, co-occurring, more frequent and widespread, chain-forming, closely related diatom, Skeletonema potamas, is also included. Livingstonia is tentatively placed in the family Thalassiosiraceae.

CYCLOTELLA MELNIKLAE SP. NOV., A NEW DIATOM FROM THE MOUNTAIN LAKES OF PRIBAIKALIE, RUSSIA

During phytoplankton studies of the mountain lakes of the Dzherginsky Nature Reserve situated East of Lake Baikal, Siberia, a new species of centric diatom was discovered, Cyclotella melnikiae Genkal et Bondarenko sp. nov. Its morphology is described using light and scanning electron microscopy. Cyclotella melnikiae is similar to Cyclotella tripartita Hakansson, Cyclotella rossii Hakansson, Cyclotella kuetzingiana Thwaites and Cyclotella chantaica Kuzmina et Genkal but is distinguished from them by the location of the rimoportulae on the valve face.

New species of freshwater diatoms from acidic localities along the Atlantic Coastal Plain of the United States

During our investigations of freshwater sites along the Atlantic Coastal Plain of North America we had the opportunity to critically study five interesting diatoms with light (LM) and scanning electron microscopy (SEM), each of which is described here as a new species. Two of the organisms are in the genus Eunotia , Eunotia lewisii Siver & Hamilton sp. nov. and Eunotia quadra Siver & Hamilton sp. nov.; two in Frustulia , Frustulia crispula Siver, Pelczar, & Hamilton sp. nov. and Frustulia inculta Siver, Pelczar, & Hamilton sp. nov.; and the last is Neidium trainori Siver & Hamilton sp. nov. All five species are reported from acidic, poorly buffered, dilute waterbodies high in dissolved humic substances. Two of the taxa are found in suites of waterbodies in close geographic proximity, two in somewhat disjunct regions, and the fifth is only known from the type locality. The relationships of each taxon to similar species are discussed.

Seven new species of freshwater diatoms (Bacillariophyceae) from the Canadian Arctic Archipelago

Seven new species of freshwater diatoms (Bacillariophyceae) from the Canadian Arctic Archipelago

TAXONOMY AND ULTRASTRUCTURE OF TWO NEW NEIDIUM SPECIES FROM LAKES IN THE SIERRA NEVADA MOUNTAINS OF NORTHERN CALIFORNIA (U.S.A.)

Neidium Pfitzer is a common genus in the freshwater diatom flora of the United States. Most Neidium taxa are large diatoms with robust features. However, several smaller, more finely organized species are also present. These species are often overlooked in collections due to their size and finer structure. Upon reviewing collections from several lakes and rivers in Northern California, some new and interesting forms were discovered. In this work observations on two Neidium species are provided that appear to be new to science. The first species is zmoderately sized, has an undulate margin and a broad, rectangular central area. The second is small, linear in shape, and has very fine striae. Light and scanning electron microscope observations on these two species are presented on both valve and girdle components, and they are compared to other small, finely ornamented taxa. These observations suggest there are still many new species of freshwater diatom to discover and describe in the U.S. flora.

The centric diatom genus Cyclotella, (Stephanodiscaceae: Bacillariophyta) from Florida Bay, USA, with special reference to Cyclotella choctawhatcheeana and Cyclotella desikacharyi, a new marine species related to the Cyclotella striata complex†

A.K.S.K. Prasad and J.A. Nienow. 2006. The centric diatom genus Cyclotella, (Stephanodiscaceae: Bacillariophyta) from Florida Bay, USA, with special reference to Cyclotella choctawhatcheeana and Cyclotella desikacharyi, a new marine species related to the Cyclotella striata complex. Phycologia 45: 127–140. DOI: 10.2216/05-13.1A new marine species of the centric diatoms of the genus Cyclotella, Cyclotella desikacharyi A.K.S.K. Prasad collected from several localities in Florida Bay, USA, where it is a dominant part of the planktonic assemblage, is described by means of light and scanning electron microscopy. Cyclotella desikacharyi is characterized by the presence of dense striae (14–19 in 10 µm) in the marginal zone and small granules all through the surface of the valve, including the central area, fultoportulae on the valve mantle located on every second or third interstria, each surrounded by three satellite pores, a pronounced tangential undulation, 3–17 valve-face fultoportulae in an arc on the uplift of the undulation and numerous discoid plastids. The new species is compared with Cyclotella striata complex; C. desikacharyi closely resembles C. striata in valve dimensions and in the structure and arrangement of alveolate striae, and in the presence of three satellite pores surrounding each fultoportula on the valve mantle; it differs from it in the stria density and the presence of siliceous granules on the entire valve surface. The new species is compared with the other closely related marine members of the genus, Cyclotella stylorum and Cyclotella litoralis. Cyclotella choctawhatcheeana Prasad, originally described from the northern Gulf Coast of Florida, is also recorded in several localities in Florida Bay and its global distribution is discussed. The evolution of euryhalinity in the genus Cyclotella is also discussed in brief.

Observations on new and rare species of freshwater diatoms from Cape Cod, Massachusetts, USA

The freshwater diatom flora of Cape Cod, Massachusetts, USA, was recently described using surface sediments from 56 largely glacial kettle lakes scattered over the narrow peninsula. During our examination we had the opportunity to study seven rare and interesting taxa with light (LM) and scanning electron microscopy (SEM). Two of these organisms, Neidium statuarium Hamilton & Siver sp.nov. and Stenopterobia pseudodelicatissima Siver & Hamilton sp.nov., are described as new species. Two new combinations, along with emended descriptions based on SEM, are provided for Nupela vitiosa (Schimanski) Siver & Hamilton comb.nov. and Tryblionella scalaris (Ehrenberg) Siver & Hamilton comb.nov. Morphological details of three additional and rare species, Neidium fasiatum Østrup, Neidium sp., and Tryblionella plana var. fennica (Hustedt) Simola are also provided. The relationships of each taxon to other similar species are discussed.Key words: Cape Cod, Neidium, new species, Nupela, Stenopterobia, Tryblionella.

A NEW SPECIES OF MERIDION (BACILLARIOPHYCEAE) FROM WESTERN NORTH CAROLINA

A new species of diatom, Meridion alansmithii sp. nov. is formally described from a soft-water montane wetland in western North Carolina, U.S.A. Meridion alansmithii is characterized by its shape in valve view, its range of length, diminished costae near the foot pole, and the location of the rimoportula. This species occurs in isolated habitats in the ancient landscape of the Southern Appalachians, an area well-known for high biodiversity and endemism in other groups of organisms.

Variable stereochemistry in highly branched isoprenoids from diatoms

C(25) highly branched isoprenoid (HBI) alkenes are ubiquitous lipids found in geochemical samples around the globe. The origins of these widespread geochemicals are believed to be restricted to a limited number of diatoms, including Haslea ostrearia (and related species), Rhizosolenia setigera, and Pleurosigma intermedium. The unsaturation of the HBI alkenes ranges from 2-6 in different species and cultures. The number of stereogenic centres is usually limited to two in the HBI alkenes due to double bond positions. The relative and/or absolute configurations for these have been determined for a range of HBI alkenes produced from different diatoms cultured under a number of growth conditions. These determinations have involved a combined spectroscopic and chromatographic analysis using NMR spectroscopy and chiral gas chromatography, respectively. HBIs isolated from Haslea spp. belong to a specific structural type which exhibit configurational diastereoisomerism, while those isolated from P. intermedium and R. setigera represent a different structural type and usually exist as mixtures of geometric isomers only. HBIs are reported from a new species of diatom whose stereochemical properties lie between those found for Haslea spp. and P. intermedium.

The marine epilithic diatom Melosira brandinii sp. nov. (Bacillariophyta) from Elephant Island, Antarctic Peninsula, with comments on some related species

A new species of epilithic diatom is described from samples collected near Elephant Island, Antarctic Peninsula. The cells of Melosira brandinii sp. nov. are joined in filamentous chains and attached by means of long mucilaginous stalks. The valves are circular with the valvar surface composed of irregularly arranged pentagonal Ioculi. Each loculus bears 6-12 pores on the external surface, opening to the innerside through rotae. The corona is only composed of coarse granules. A mantle is well developed, presenting rimoportulae and bearing coarse granules, which are more concentrated at the mantle edge. Comparisons with the related species Melosira arctica, M. moniliformis and M. nummuloides are made. Additionally, photomicrographs of M. arctica from the type material and Barents Sea, and of M. moniliformis from estuaries of Southern Brazil are included.

The marine epilithic diatom Melosira brandinii sp. nov. (Bacillariophyta) from Elephant Island, Antarctic Peninsula, with comments on some related species

A new species of epilithic diatom is described from samples collected near Elephant Island, Antarctic Peninsula. The cells of Melosira brandinii sp. nov. are joined in filamentous chains and attached by means of long mucilaginous stalks. The valves are circular with the valvar surface composed of irregularly arranged pentagonal Ioculi. Each loculus bears 6-12 pores on the external surface, opening to the innerside through rotae. The corona is only composed of coarse granules. A mantle is well developed, presenting rimoportulae and bearing coarse granules, which are more concentrated at the mantle edge. Comparisons with the related species Melosira arctica, M. moniliformis and M. nummuloides are made. Additionally, photomicrographs of M. arctica from the type material and Barents Sea, and of M. moniliformis from estuaries of Southern Brazil are included.

THE GENUSNITZSCHIA: THREE NEW SPECIES FROM THE EQUATORIAL PACIFIC OCEAN

Three new species of small diatoms are described from the Equatorial Pacific: Nitzschia johnmartinii, N. concordia and N. reimeri. The first two taxa were identified from rough cultures of Equatorial Pacific water enriched with iron, whereas the third species was identified from these same rough cultures and other localities along the 140° W meridian.

CLIMACONEIS STROMATOLITIS, A NEW SPECIES OF DIATOM FROM SHARK BAY, WESTERN AUSTRALIA

The structure, morphology and ecology of Climaconeis stromatolitis a new species of diatom associated with living stromatolites in Shark Bay, Western Australia are presented. This species is distinguished from other described species of Climaconeis by the presence of a pair of H-shaped plastids, its strong stauros and fine striae.