Search

Differences in limnological and hydrological conditions between storage and run-of-river reservoirs caused variations in phytoplankton assemblages along the two types of reservoirs. Instead of exploring variations in phytoplankton assemblages along one type of reservoir, this study identified similarities and differences in phytoplankton assemblages along two types of reservoirs. Phytoplankton assemblages from Xiaowan (storage reservoir) and Manwan (run-of-river reservoir) reservoirs in the Lancang River, China were used as case study. Taxonomic approach and functional group method were used to compare phytoplankton assemblages at sampling sites located in impounded areas of reservoirs, free-flowing areas directly below reservoirs, and free-flowing intermediate areas between the two contrasting reservoirs. With the reduction of reservoir disturbance, phytoplankton assemblages in free-flowing intermediate areas between reservoirs will recover to rich and diverse. Because of the inoculation and dispersion of phytoplankton from the upstream reservoir, dominant functional groups at the sampling sites located in impounded areas of reservoirs and free-flowing areas directly below reservoirs were mainly represented by groups that prefer long water residence times. The functional group TB (Nitzschia lorenziana) and W2 (Strombomonas ensifera) could be used as useful indicators to determine hydrological conditions due to their strong sensitivity to water residence times. Results of the linear redundancy analysis demonstrated that phytoplankton assemblages were mainly affected by DO and flow. These results should aid river managers in acquiring better insight into the effect of cascade reservoirs on the biomass and structure of phytoplankton in the aquatic ecosystem.

Colacium minimumFott & Komárek, known so far from a few localities in Central Europe (Czech Republic), is reported here for the first time from Asia (Thailand). This epiphytic species was found growing on eight taxa of loricated euglenoids. The process of surface colonization ofTrachelomonasEhrenb. andStrombomonasDeflandre taxa byC. minimumin natural populations is briefly discussed and originally documented using LM and SEM.

Five new species and one new variety of loricate euglenoid taxa were discovered in Thailand: Strombomonas starmachii Duangjan & Wołowski, S. chiangmaiensis Duangjan, Trachelomonas peerapornpisalii Duangjan & Wołowski, T. thailandicus Duangjan & Wołowski, T. reticulato-spinifera Duangjan and T. hystrix var. paucispinosa Prowse. We propose to raise the variety to species level [T. paucispinosa (Prowse) Duangjan & Wołowski, stat. et comb. nov.]. The morphology and fine lorica ultrastructure of the species are described. All taxa are documented by SEM images and some by LM micrographs.

Twenty-six taxa of the genus Strombomonas DeflanDre (Euglenophyta) were determined from samples collected from several freshwater bodies located in the Piedmont region of central New Jersey, USA. In addition, twelve taxa were examined in detail by scanning electron microscopy (SEM). On the basis of these observations one new species is proposed: S. americana. Details of envelope ultrastructure are illustrated.

Ten taxa belonging to Chlorophyceae, Cyanophyceae, Bacillariophyceae and Euglenophyceae, and one with an uncertain taxonomic position have been described in this paper. Of these, 10 taxa have been found to be globally rare and new records for Bangladesh , whereas Strombomonas islamii Khondker sp. nov. has been described as new to science. Keywords: Rare species; Strombomonas islamii Khondker; Ponds; Bangladesh . DOI: 10.3329/bjpt.v16i1.2734 Bangladesh J. Plant Taxon. 16(1): 1-8, 2009 (December)

Most genera and many species of euglenophytes exist worldwide. They usually occur during the summer months in slow-flowing and stagnant waters, rich with organic substances. Euglenophytes of the Danube River in Serbia were studied at 16 localities during 2002-2003. A total of 61 taxa were found, 21 belonging to the genus Euglena Ehr., eight to Lepocinclis Perty, 15 to Phacus Duj., six to Strombomonas Defl., and 11 to Trachelomonas Ehr. The highest number of taxa (35) was recorded at Backa Palanka during September 2002, but at the Tekije locality no euglenophytes were detected at all.

A biogeographical and taxonomic study on Strombomonas and Trachelomonas, which are often abundant in polluted environments, was undertaken in south-eastern USA. Light and scanning electron microscope analysis allowed the identification of 68 taxa, among them five Strombomonas and 63 Trachelomonas. All are documented with original SEM and LM micrographs. Twenty-seven Trachelomonas taxa are reported as new from this region. Variability in lorica microstructure is demonstrated for T. curta var. curta, T. pusilla var. punctata, T. rotunda, T. hispida var. coronata and T. scabra var. scabra from natural habitats. Physicochemical parameters for water quality at the collection sites are reported.

Since the separation of the Trachelomonas Ehrenberg subgroup "Saccatae" into a new genus, Strombomonas Deflandre (1930), there has been some question as to its validity. Deflandre's separation was based entirely on characteristics of the lorica, including the shape of the lorica, the lack of a distinctive collar, possession of a tailpiece, lack of ornamentation, and the ability of Strombomonas species to aggregate particles on the surface of the lorica. Recent molecular analyses indicated that the loricate taxa {Trachelomonas and Strombomonas) formed a single monophyletic clade; however, the phylogenetic relationship of Strombomonas to Trachelomonas remains unclear because only two Strombomonas taxa have been sequenced to date. In this study, we evaluated the monophyly of the loricate genera using two sets of morphological characters, lorica development and pellicle strip reduction. Lorica development in Strombomonas occurred from the anterior of the cell to the posterior, forming a shroud over the protoplast. In Trachelomonas, a layer of mucilage was excreted over the entire protoplast, followed by creation of the collar at the anterior end. Taxa from both genera underwent exponential strip reduction at the anterior and posterior poles. In Strombomonas only one reduction was visible in the anterior pole, whereas in most Trachelomonas species two reductions were visible. Likewise, Strombomonas species possessed two whorls of strip reduction in the posterior end compared with a single whorl of strip reduction in Trachelomonas species. These morphological characters support the separation of Trachelomonas and Strombomonas as distinct genera.

this paper deals with a qualitative analysis of the Class Euglenophyceae from Negro river, Uruguay South America. Samples were collected between November 1994 and February 1995. A total of 54 taxa were recorded, 3 belonging to Lepocinclis, 3 to Phacus, 26 to Strombomonas and 22 to Trachelomonas. On the basis of these observations we propose one new variety S. scabra var. piriformis and a new forma S. urceolata var. elegans fo. americana. Twenty three taxa have been examined by means of scanning electron microscopy. The high species richness was registered at Paso Ramirez (PR). Some parameters physical-chemicals are also given.

Summary: Three pigmented flagellates: Gloeomonas mamillosa, Lobomonas tubulata (Chlamydomonadales, Chlorophyceae) and Strombomonas quadrangularis (Euglenales, Euglenophyceae) are described as new taxa from material collected in two freshwater bodies located in the Municipality of Rio de Janeiro, Rio de Janeiro State, southeastern Brazil.

espanolSe estudian siete especies de Euglenoficeas loricadas, 2 pertenecientes al genero Strombomonas y5 de Trachelomonas. Se analiza la microarquitectura de la lorica a microscopio optico y electronico de barrido, describiendo los elementos ornamentales de cada especie. Destacamos el estudio de tres poblaciones de Trachelomonas, dos de ellas incluidas provisionalmente en T. nigra y T. similis respectivamente, mientras que en la tercera: Trachelomonas sp., con una gran variabilidad morfologica de la lorica, destaca la existencia de un anillo de perforaciones que se disponen alrededor del poro flagelar EnglishSeven species of Euglenophyceae with lorica (2 Strombomonas and 5 Trachelomonas) haven been studied. We analyzed their lorica microarchitecture by means of ligh microscopy and scanning electron microscopy, enumerating their different ornamental elements. We stand out the study of three population of Trachelomonas, two of them are provisionally included in T. nigra and T. similis respectively. The third one: Trachelomonas sp. show a large morphological variability with only one common ornamental character within of the population: a ring of perforations around the flagellum pore.

Foram identificados 34 táxons específicos e infra-específicos do gênero Strombomonas Defl. resultado do estudo de amostras qualitativas no Parque Estadual Delta do Jacuí, localizado a 29°56'-30°03'S e 51°12'-51°18'W. As amostragens foram realizadas em 25 ambientes aquáticos em abril/1993 e janeiro/1994 e maio/1998 a setembro/1999. Strombomonas borystheniensis, S. ensifera, S. gibberosa, S. girardiana, S. scabra, S. triquetra var. torta e S. verrucosa foram os táxons mais freqüentes na área, ocorrendo em mais de 50% dos locais amostrados, destacando-se S. verrucosa pela ampla distribuição na área do Parque, com a ocorrência em 96% dos locais estudados. Strombomonas chodatti, S. cuneata, S. moreniensis,S. napiformis var. brevicollis são primeiras citações de ocorrência para o Estado e Brasil. S. confortii,S. fluviatilis var. major, S. morenensis, S. scabra var. intermedia e S. scabra var. ovata f. minor ocorrem exclusivamente na América do Sul. São realizadas considerações taxonômicas e ecológicas sobre o gênero, assim como é fornecida sua distribuição nacional e mundial. Thirty four specific and infra-specific taxa of the genus Strombomonas Defl. were identified as the result of the study of qualitative samples from Jacuí Delta State Park, that is located for 29°56'- 30°03'S and 51°12'-51°18'W. Sampling were carried out in 25 stations from April/1993 to January/1994 and May/1998 to September/1999. Strombomonas borystheniensis, S. ensifera, S. gibberosa, S. girardiana, S. scabra, S. triquetra var. torta and S. verrucosa were the most frequent taxa in the area, occuring in more than 50% of the samples, being distinguished S. verrucosa for its wide distribution in the area of the Park, with the occurrence in 96% of the studied places. Strombomonas chodatti, S. cuneata, S. moreniensis and S. napiformis var. brevicollis,were registered for the first time to the State and Brazilian territory. S. confortii, S. fluviatilis var. major, S. morenensis, S. scabra var. intermedia and S. scabra var. ovata f. minor are taxa that occur exclusively in South America. Taxonomic and ecological considerations are supplied as well as its national and world distribution.

A taxonomic revision of the Euglenophyta found exclusively in South America is presented. The taxonomy, geographical distribution and critical analysis of the synonyms are given. More than two hundred species and infraspecific entities from South America are described, many of them recorded several times in different regions. The genus Trachelomonas comprises the highest number of new taxa, reaching more than 100 entities. It is followed by Phacus (48 taxa), Strombomonas (33 taxa), Euglena (15 taxa) Lepocinclis (14 taxa), and Distigma, Entosiphon and Sphenomonas with one new taxon each.

The Euglenophyta include four genera of Euglena-like cells enclosed in a lorica. Two of these genera, Trachelomonas and Strombomonas, are free swimming. These taxa have been differentiated and classified at the generic and species level based primarily on the morphology of their lorica. Numerous SEM studies have been conducted, yet few, if any, TEM descriptions exist, especially for Strombomonas. This study describes both the outer lorica and internal ultrastructure for Strombomonas sp. isolated from a fresh water pond in New Jersey. Additionally, we describe the release of daughter cells from the lorica following cell division. Two cells were observed within a single Strombomonas lorica following cytokinesis. When exposed to the light of the microscope, one or both of the cells emerged through the neck of the lorica. The released cells could easily be mistaken for Euglena species.

Envelopes of Strombomonas conspersa, like those of Trachelomonas, may range in colour from hyaline to dark brown. Cytochemical staining with Alcian Blue reveals differences between light and dark envelopes of both genera: acidic and sulphated glycosaminoglycans (mucopolysaccharides) are present in all the organic matrices; however, in dark envelopes the sulphate groups are masked by the Mn and are detectable only when the metal is removed. The TEM and EM-EDS comparative studies of the microarchitecture and elemental composition of envelopes of Strombomonas conspersa and several species of Trachelomonas show similar results: hyaline envelopes are characterized by unmineralized strands that anastomose to form a complex reticulum, whereas dark envelopes, heavily mineralized with Mn, are composed of dense needle-like components enmeshed in a mucilaginous matrix. In the light of these findings, we propose that Strombomonas conspersa be removed to its original taxonomic position in the genus Trachelomonas, as T...

Though about 120 taxa ofTrachelomonas and 13 taxa ofStrombomonas are recorded from the Indian region, only about 60 taxa have been described fully. These descriptions are scattered in different journals. The present account brings together 70 taxa ofTrachelomonas and 36 ofStrombomonas collected from north-east, central and south India during 1937–1976, with keys and figures for their identification. Of these, 3 species ofTrachelomonas, viz.Trachelomonas costatus, Trachelomonas assamensis andTrachelomonas joysagarensis and 5 species ofStrombomonas, viz.Strombomonas hexagonalis, Strombomonas madraspatensis, Strombomonas vaseformis, Strombomonas indica andStrombomonas tortuosa are considered new. Sixteen varieties and forms ofTrachelomonas and 7 varieties and forms ofStrombomonas are also considered new. Nine species and 12 varieties ofTrachelomonas and 11 species and 7 varieties ofStrombomonas are new records for the Indian region. A list of 87 taxa ofTrachelomonas and 7 ofStrombomonas, the major part of which are only just listed by various authors for the Indian region, are given at the end of each genus. Some ecological observations onTrachelomonas andStrombomonas are given. The majority ofTrachelomonas species occurred in ponds with a fairly high degree of organic matter and fairly high nitrates and phosphates and low alkalinity during the rainless months of December to May.Strombomonas spp. were usually more common in ponds with higher alkalinity.Strombomonas verrucosa var.conspersa andTrachelomonas volvocina tolerated a wide range of total alkalinity. Excessive heat and sunlight or continuous rains seemed to have an adverse effect on the latter organism.

The paper deals with a systematic account of 17 euglenoid phytoplakton. Of these, seven taxa belong to Lepocinclis and seven to Strombomonas . The other three taxa are Astasia cylindrical Pringsheim , A. pygmaea Skuja and Menoidium tremulum Skv . T he taxa are reported from some pond ecosystems located in Pirojpur and Barisal districts of Bangladesh. Keyword s : Phytoplankton, New records, Bangladesh, Lepocinclis , Strombomonas , Astasia , Menoidium , Ponds  DOI: 10.3329/bjpt.v15i2.1740  Bangladesh J. Plant Taxon. 15(2): 107-114, 2008 (December)