New and interesting desmids (Zygnematales, Chlorophyceae) collected from Brazil and Argentina

The morphology and taxonomy of nine desmid taxa belonging to the three genera Closterium, Euastrum and Cosmarium are studied based on freshwater algal collections from Brazil and Argentina. They represent five new varieties (Closterium cynthia De Notaris var. minutum Kanetsuna var. nov., Euastrum attenuatum Wolle var. saitoi Kanetsuna var. nov., Cosmarium laticollum Delponte var. minutum Kanetsuna var. nov., Cosmarium pseudovariolatum Grönblad var. major Kanetsuna var. nov. and Cosmarium taxichondrum Lundell var. yamagishii Kanetsuna var. nov.), two new forms (Euastrum hypochondrum Nordstedt var. hypochondrum f. divergens Kanetsuna f. nov. and Euastrum insulare (Wittrock) Roy var. silesiacum (Gronblad) Krieger f. brasiliense Kanetsuna f. nov.) and one new status (Cosmarium pseudovariolatum Gronblad var. incrassatum (Scott et Gronblad) Kanetsuna f. elonga‐tum (Scott et Gronblad) Kanetsuna stat. nov.). In addition, a new combination (Cosmarium pseudovariolatum Gronblad var. incrassatum (Scott et Gronblad) Kanetsuna comb, nov.) is proposed.     

黑龙江扎龙国家级自然保护区鼓藻类植物中国新记录

于2011年5月(春季)、7月(夏季)和10月(秋季),先后3次对黑龙江扎龙国家级自然保护区进行鼓藻类植物调查,并对采集到的57份标本进行鉴定。结果发现,有6个分类单位为鼓藻类植物中国新记录,隶属于5个属,分别为:微小胶球鼓藻(Cosmocladium pusillum Hilse),中凹鼓藻(Cosmarium medioretusum Coesel),近前膨胀鼓藻锥形变种(Cosmarium subprotumidum var.pyramidale Coesel),双孢辐射鼓藻美国变种[Actinotaenium diplosporum var.americanum(West et West)Teiling],双臂角星鼓藻优美变种[Staurastrum bibrachiatum var.elegans(West et West)Prescott],冠毛多棘鼓藻钩状变种波兰变型(Xanthidium cristatumvar.uncinatumf.polonicumGutwingski)。     

Indonesian desmids

Summary There are described 526 desmid taxa found in 49 freshwater algal collections from Kalimantan (Borneo), Java, Bali and Sumatra, including 152 new taxa in the genera Closterium, Pleurotaenium, Euastrum, Micrasterias, Cosmarium, Arthrodesmus, Xanthidium, Staurastrum, Onychonema, Bambusina, and Desmidium.     

Some rare desmids (Zygnematophyceae) from Central Europe

The morphology and taxonomy of eight rare desmids (Zygnematophyceae) from Central Europe are studied, i.e. six taxa from Slovakia [Tortitaenia bahusiensis (Nordstedt et Lütkemüller) Coesel, Closterium limneticum Lemmermann var. fallax R??i?ka, Euastrum sublobatum de Brébisson in Ralfs, morpha, Cosmarium simplicius (W. et G.S. West) Grönblad, Pachyphorium canadense (Irénée-Marie) G. H. Tomaszewicz et Hindák, stat. et comb. nova, Staurastrum bloklandiae Coesel et Joosten], one species from Poland (Spirotaenia bacillaris Lütkemüller) and Austria (Cosmarium geminatum Lundell). All desmids taxa are new records for the country of their origin.     

New and interesting cases of conjugating desmids from Lapland

A number of desmid samples collected in Lapland appeared to be remarkably rich in zygospores. The spore morphology of Euastrum sinuosum Lenorm. ex Arch., Cosmarium tumidum Lund., C. isthmochondrum Nordst., Staurastrum dilatatum Ehr. ex Ralfs, Actinotaenium wollei (W. & G. S. West) Teil. ex Růž. & Pouz. and A. didymocarpum (Lund.) comb, nov., either when hitherto unknown or requiring a critical discussion is extensively treated. A new species, Cosmarium taxillus (with zygospores) is described.
Repeatedly recorded incidences of a disturbed zygospore development and the grey to black pigmentation of the mesosporium are discussed in connection with the possible effect of habitat factors.     

Polyphasic evaluation of Xanthidium antilopaeum and Xanthidium cristatum (Zygnematophyceae,Streptophyta) species complex

We investigated twenty‐six strains of Xanthidium antilopaeum Kütz. and seven strains of X. cristatum Ralfs isolated from various European localities or obtained from public culture collections. A combination of molecular, geometric morphometric, and morphological data were used to reveal the patterns of the phylogenetic and morphological differentiation of these taxonomically very compli‐cated desmid taxa. The molecular data based on trnG^ucc and ITS rDNA sequences illustrated the monophyly of both the complexes, which indicated that their traditional morphology‐based discriminative criteria, such as the different number of spines, may generally continue to be considered relevant. The single exception was X. antilopaeum var. basiornatum B. Eichler et Raciborski, which was positioned outside the X. antilopaeum/cristatum clade. The independent status of this taxon was also confirmed on the basis of the geometric morphometric data, so that we concluded that it probably represents a separate species. Within X. cristatum complex, the traditional varieties X. cristatum var. cristatum Ralfs, X. cristatum var. uncinatum Ralfs, and X. cristatum var. scrobiculatum Scott et Grönblad turned out to be separate taxa. Conversely, X. cristatum var. bituberculatum Lowe lacked any taxonomical value. Our data on X. antilopaeum illustrated extensive phylogenetic as well as phenotypic variability within this species complex. However, our data did not result in any unambiguous pattern that would allow sound taxonomic classification. Finally, we also found out that the morphologically peculiar Staurastrum tumidum Ralfs belongs to the genus Xanthidium based on the combined rbcL + cox III data set. Consequently, this species was formally transferred to this genus.     

Rare and new desmids (Desmidiaceae, Chlorophyta) from Japan

A number of rare or unknown desmid species were revealed in samples collected from a range of aquatic habitats in Japan. In the present paper we describe one new species of the family Desmidiaceae, Staurastrum tsukubicum sp. nov. and report the presence in Japan of two species, Staurastrum levanderi Grönbl. and Cos-marium dilatatum Lütkem. in Järnefelt et Grönblad, previously found only in Europe. One taxon, Euastrum englerii Schmidle var. madagascariense Bourr. et Manguin, is renamed as Euastrum biverrucosum nom. nov. et stat. nov. The morphology of these taxa was studied using light and scanning electron microscopy and their taxonomic affinities are discussed.     

Three new desmid taxa from West Africa,including two asymmetrical forms

Micrasterias echinata sp. nov., from Sierra Leone, is a species believed to be unique among the symmetrical members of the genus in having all the processes paired about the frontal plane of symmetry, none being in the plane itself. Euastrum bombayense Brandham nom. nov. var. gracile var. nov. and Cosmarium dolabriforme sp. nov., from Nigeria, both show marked asymmetry.     

Application of desmid diversity in assessing the water quality of 12 freshwater resources in Thailand

Desmids from 12 freshwater resources in the northern part of Thailand were investigated during 2002 to 2003. A total of 91 taxa were found. They belonged to 17 genera: Actinotaenium, Spirotaenia, Netrium, Gonatozygon, Pleurotaenium, Closterium, Euastrum, Micrasterias, Cosmarium, Cosmocladium, Stuarastrum, Staurodesmus, Xanthidium, Teilingia, Spondylosium, Hyalotheca and Desmidium. The water qualities in all the water resources were classified as oligotrophic to meso-eutrophic by trophic status. The taxa that could possibly be used as bioindicators of trophic state were Staurastrum gutwinskii, Spondylosium pandurifoemae, Cosmarium capitulum, C. mediosrobiculatum var. egranutum, S. tortum, Closterium gracile var. elongatum, C. kuetzingii and Closterium dianae var. dianae. The most frequently found taxa were Staurastrum limneticum var. burmense, S. tetracerum var. tetraerum, Pleurotaenium trabecula, Closterium ehrenbergii var. ehrenbergii and C. kuetzingii. The rare taxa in this study were Actinotaenium sp. Spirotaenia condensata, Pleurotaenium burmense var. dacchense and Micrasterias apiculata. Forty-one taxa of desmids were identified as new records for Thailand. Presented at the 6th Meeting of the Asian Pacific Society of Applied Phycology, Manila, Philippines.     

Seasonal periodicity of planktonic desmids in oligotrophic lake Grane Langsø, Denmark

60 desmids were identified from plankton samples collected during 20 years, bimonthly, or monthly in 5 of the years. Only 5 desmids were perennial, performing cell divisions in a frozen lake at PAR at only 5 cal cm ^–2 day ^–1, below ice-cover. The greatest number of desmids per 100 ml lake water was found in September; it never exceeded 150. Owing to a concentration of free CO₂ of only 0.02 mM l^–1 and a HCO _inf3 ^sup– concentration of 0.002 mM l^–1 the densities of desmid cells were often smaller than 1 cell per 100 ml lake water. A density of 1 cell per 1 ml was attained only by Staurastrum longipes, a desmid showing temporal variation. The relation of the compound phytoplankton quotient to two components of the CO₂-system is discussed. Three new taxa are described: Staurastrum brachiatum Ralfs var. bicorne n. var., Staurastrum thomassonii n.sp. and Xanthidium antilopaeum Kütz. f. bimaculatum n.f..     

Some New Taxa of Desmidiaceae from the Hengduan Mountains Region of China

Fifteen new taxa of the Desmidiaceae are described and illustrated from the Hengduan Mountains region of China. They are Euastrum gemmatum f. denticulatum, Cosmarium asphaerosporum var. subcapitum, C. dovrense var. fontanum, C. foveolatum, C. sichuanense, C. subdanicum var. granulatum, C. subsuperbum, C. tibeticum var. papilliferum, C. venustum var. arcuatum, C. yunnanense, Staurastrum elaticeps var. eximium, S. longiradiatum f. basispinulosum, S. pseudosebaldi var. compactum f.reductum, S. sebaldi var. ornatum f. spiniferum,S. sonthalium f. spiniferum.     

Desmidiacee della torbiera del Vedes (Trento)

Abstract

Desmids of the peat-bog of Vedes (Trento, North-Italy). A list of 27 Desmids s.l. (Desmidiaceae, Closteriaceae and Mesotaeniaceae) observed in some samples coming from the peat-bog of Vedes (Trento, North-Italy) is reported. This is a high moor bog situated at an altitude of 1496 m and rich in Sphagnum species (Sphagnum medium, S. fuscum, S. robustum, S. laricinum, etc.). The most interesting Desmids found are: Actinotaenium cucurbita, A. crassiusculum, Bambusina brebissonii, Penium polymorphum, Tetmemorus brebissonii, T. laevis, Closterium intermedium, Cosmarium amoenum, Euastrum insigne, Netrium digitus and Staurastrum erostellum, the last one being a very rare species found for the first time in Italy; thirteen entities are new for the algal flora of Trentino-Alto Adige.     

Interesting taxa ofStaurastrum Meyen (Desmidiaceae) from Karnataka State (India)

Algae were collected from a paddy field at Belgaum during August 1985. Two new taxa ofStaurastrum Meyen (viz.S. quebecense Irénée-Marie fa.minor Bongale fa.nov. andS. sebaldii Renisch var.triangularis Bongale var. nov.) and two other taxa showing major variations (viz.S. gracile Ralfs. var.elongatulum West et West fa. andS. leutkemuelleri Donat et Ruttner ms. fa.) are reported.     

SPECIES PHYLOGENY OF COSMARIUM AND STAURASTRUM (DESMIDIACEAE) BASED ON RBC L SEQUENCES

Cosmarium and Staurastrum are the two most diverse genera of placoderm desmids (Family Desmidiaceae), with approximately 1100 and 800 species, respectively. Phylogenetic analysis of relationships of species has been extremely difficult. In a monograph of North American placoderm desmids, Prescott et al. described early phylogenetic work that concluded Staurastrum to be polyphyletic and certainly polymorphic. Likewise, Cosmarium has also been viewed as polyphyletic, and a number of workers have proposed splitting these genera. The classical view of West and West grouped species within each genus into two divisions and 6–8 sections based on wall features and semicell shape. We sequenced rbc L from 18 species of Cosmarium (2 divisions, 7 sections) and 12 species of Staurastrum (2 divisions and 7 sections) and performed a phylogenetic analysis (parsimony, maximum likelihood, bootstrap) using other placoderm desmids and Zygnematales as outgroups. The results exhibit little support for the monophyly of sections or divisions of the two genera. Furthermore, although there is support for the monophyly of clades within each genus, there is also support for a separate clade containing species from both genera.     

New taxa ofCosmarium Corda (Desmidiaceae) from Karnataka State,India

Six new taxa including two new species (Cosmarium bourrellyi Bongale sp. nov. andC. desikacharyi Bongale sp. nov.) and four new varieties (C. auriculatum var.protrusum Bongale var. nov.,C. pachydermum var.inflatum Bongale var. nov.,C. pseudoconnatum var.tuberculans Bongale var. nov. andC. quadrum var.rotundatum Bongale var. nov.) are reported. Algae were collected from a paddy field at Belgaum.     

The Seasonal Succession of Biotic Communities in Wetlands of the Tropical Wet-and-Dry Climatic Zone: III. The Algal Communities in the Pantanal of Mato Grosso,Brazil, with a Comprehensive List of the Known Species and Revision of two Desmid Taxa

Studies conducted over a period of about 14 years in the northern part of the Pantanal of Mato Grosso revealed that there is a pronounced seasonal succession of algal communities resulting from periodic flooding and desiccation. Generally, during the high water period, the microflora is very sparse but species-rich and dominated by the Desmidiales, which are notably inhabitants of mineral-poor waters. During the dry season, the rapidly evaporating pools of water in the Pantanal often support extremely large concentrations of algae belonging mainly to other orders of Chlorophyta and to Euglenophyta. The seasons of rising and falling water levels are characterized by a mixed flora containing elements typical of both the high water and dry seasons, according to the local conditions that prevail. Dense beds of filamentous algae in the family Zygnemataceae are generally encountered only where there is inflow of nutrient-rich water or another source of local eutrophication. The algae present belong overwhelmingly to cosmopolitan or circumtropical species. Their presence and relative abundance seem to be determined primarily by the concentrations of inorganic nutrients in the water. Of the 337 species observed, most are reported for the first time from the Pantanal, and the list of species provides the only comprehensive catalog of autotrophic microorganisms yet compiled for this vast wetland. The physical and chemical characteristics of the habitats in which the various algae occur and their relationships with the macrophyte communities are discussed. One variety of desmid is redescribed and given a valid name: Staurodesmus convergens (Ehrenberg ex Ralfs) Lillieroth var. teilingii DE-Lamonica-Freire nom. nov., and the taxonomic status of Cosmarium galiciense (Gutwinski) DE-Lamonica-Freire comb. nov. is revised.     

Notes on the variation,geographical distribution and ecology ofEuastrum insulare var.basichondrum (Chlorophyta,Desmidiaceae)

Euastrum insulare var.basichondrum, morphologically taking an intermediate position in respect ofCosmarium trilobulatum var.basichondrum andEuastrum bipapillatum, appeared to exhibit such a wide range of variation that it may be considered identical to the other two above-mentioned taxa. This taxon, after having been studied with both light- and scanning electron microscopy, is re-diagnosed. This alga occurs in wet moss cushions in weakly acid to neutral environments. The relation between such a terraqueous habitat and the principally arctic-alpine distribution and a conceivably associated process of speciation is discussed.     

POLYMORPHISM IN THE DESMID XANTHIDIUM REGULARE AND ITS TAXONOMIC IMPLICATIONS

This paper refers to a case of polymorphism in the desmid genus Xanthidium Ehr. It is based on material from Lake Dais Irmaios, the main body of water in the Zoological and Botanical Garden in Recife, Pernambuco, northeastern Brazil, collected at 4 different times of the year during 1967 and 1968. A detailed examination of almost 1300 specimens showed an enormous variety in form of Xanthidium regulare Nordst., X. fragile Borge, and X. pseudoregulare Borge, thus allowing the authors to draw the following conclusions: (1) the name X. regulare Nordst. should be retained until further and more detailed studies on form variation within the species are available; (2) the names X. regulare Nordst. var. asteptum Nordst. in Borge, X. regulare Nordst. var. sexangulare Grönbl., X. regulare Nordst. var. sexangulare Grönbl. f. robustior Grönbl., X. fragile Borge, X. fragile Borge forma, and X. fragile Borge var. depauperatum Borge should be considered synonymous, all referring to a single variety of X. regulare Nordst., var. asteptum Nordst. in Borge emend. C. Bic. & L. M. Carv.; (3) X. pseudoregulare Borge must be treated as a variety of X. regulare Nordst. and must be called X. regulare Nordst. var. pseudoregulare (Barge) C. Bic. & L. M. Carv. Finally, a key is given to the 3 varieties of X. regulare Nordst. proposed in the present paper.     

The pH-related morphological variations of two acidophilic species of Desmidiales (Viridiplantae) isolated from a lowland peat bog,Czech Republic

Morphological variation related to pH was investigated in two acidophilic desmid species (Euastrum binale var. gutwinskii and Staurastrum hirsutum) utilizing geometric morphometric methods. Clones isolated from acidic habitats were cultured using a range of pH values from 3.5 to 6.5. The plasticity of ensuing populations was quantified and illustrated by the general Procrustes superimposition of landmarks placed along the outline of cells and subsequent statistical analyses of shape data. In both species, there was a significant effect of pH on the morphology of cells. In Staurastrum hirsutum, the pH-related morphological change was accompanied by a decrease in the size of cells cultured at a higher pH. However, in Euastrum binale, cell size did not differ in relation to pH, but cell shape was characterized by a deepening of the incisions between cell lobes at higher pH. In both species, cell complexity based on surface-to-volume ratio was positively correlated with increasing pH. We conclude that by manipulating their surface-to-volume ratios, these desmid species can respond to pH variations in their environment.     

Morphology of Cell Wall Pore Channels in the Genus <Emphasis Type="Italic">Euastrum</Emphasis> Ralfs (Desmidiales)

The study of the cell wall structure was performed for ten species of Euastrum: E. ansatum (Ehrenb.) Ralfs, E. bidentatum Näg., E. binale (Turp.) Ehrenb. ex Ralfs, E. dubium Näg., E. elegans (Bréb.) Kütz. ex Ralfs, E. germanicum (Schmidle) W. Krieger, E. oblongum (Grev.) Ralfs ex Ralfs, E. pectinatum Bréb. ex Bréb. in Ralfs, E. validum West et G.S.West, E. verrucosum (Ehrenb.) ex Ralfs. The investigation of the cell wall ultrastructure has established for the first time that the pore canal in 6 of 10 species always has a coiled form to some degree. Three species (E. germanicum, E. pectinatum, and E. verrucosum) have both coiled and straight canals, and E. ansatum has only straight ones. A new type of pores (P7), typical only for representatives of the genus Euastrum, was also noted. In addition, a simple and effective method of preparing desmidium algal cells for investigation with transmission electron microscope has been developed.