Browsing by Autor "Luc Éctor"

Now showing 1 - 16 of 16

Analysis of the type of Fragilaria construens var. subsalina (Bacillariophyceae) and description of two morphologically related taxa from Europe and the United States
(Taylor & Francis, 2011) Cristina Cejudo‐Figueiras; Eduardo A. Morales; Carlos E. Wetzel; Saúl Blanco; Lucien Hoffmann; Luc Éctor
Cejudo-Figueiras C., Morales E.A., Wetzel C.E., Blanco S., Hoffmann L. and Ector L. 2011. Analysis of the type of Fragilaria construens var. subsalina (Bacillariophyceae) and description of two morphologically related taxa from Europe and the United States. Phycologia 50: 67–77. DOI: 10.2216/09-40.1Fragilaria construens var. subsalina is a common diatom found in a wide variety of aquatic systems worldwide. It was described by Hustedt (1925) Hustedt F. 1925. Bacillariales aus den Salzgewässern bei Oldesloe in Holstein. Mitteilungen der Geographischen Gesellschaft und des Naturhistorischen Museums in Lübeck, 2. Reihe, Heft 30: 84–121. [Google Scholar] from brackish waters in Oldesloe, Germany; a lectotype specimen was established by Simonsen (1987) Simonsen R. 1987. Atlas and catalogue of the diatom types of Friederich Hustedt. J. Cramer, Berlin - Stuttgart. Vol. 1 (catalogue). 525 pp. Vol. 2, 597 pp., pls 1–395; Vol. 3, 619 pp., pls 396–772. [Google Scholar]. We analysed the ultrastructure of specimens from the lectotype material by means of light (LM) and scanning electron microscopy (SEM) and show that this taxon should be placed at the species level within the genus Pseudostaurosira (as Pseudostaurosira subsalina). A similar but distinct taxon from the United States, found in waters with low electrolyte content, is proposed as a new species of Pseudostaurosira, namely Pseudostaurosira americana sp. nov. We also describe a second new species from Spain (Pseudostaurosira alvareziae sp. nov.), found in waters with moderate conductivity, which was misidentified as P. subsalina in the past. A morphometric analysis of the valve shape supports the morphological separation between the three species. The present study clarifies the taxonomy, ecology and systematic position of these three taxa and provides a comparison with other, similar taxa.
Characterization of a new species in the genusDidymospheniaand ofCymbella janischii(Bacillariophyta) from Connecticut, USA
(Taylor & Francis, 2016) Diba A. Khan-Bureau; Eduardo A. Morales; Luc Éctor; Michael S. Beauchene; Louise A. Lewis
Two non-native stalk-forming diatoms that were recently observed in the West Branch of the Farmington River, a tributary of the Connecticut River in Connecticut (USA), are characterized morphologically and barcode marker sequences were obtained for each of them. Cymbella janischii, the dominant stalk-forming species during the summer of 2012, previously had not been found in the northeastern USA. Samples of C. janischii were examined microscopically and used to obtain four sequences of the barcode marker, the V4 region of the 18S rDNA gene. Phylogenetic analysis indicated that the four independent sequences of C. janischii were distinct from, but most closely related to, published sequences of C. janischii from Idaho and C. mexicana from Texas, USA. A second non-native stalk-producing diatom, resembling Didymosphenia geminata, was found in November 2012 – June 2013 and first reported as Didymosphenia sp. Over this period, the observed cells had a compressed morphology and were consistently small compared with D. geminata. Sequences of the V4 region, obtained from three independent direct polymerase chain reactions (PCR) of single cells isolated from the Connecticut samples, indicated a close relationship to three published sequences of D. geminata from Italy, New Zealand and the USA, and to D. siberica and D. dentata from Russia. Frustules of the cells used in the PCR reactions were recovered and examined using scanning electron microscopy, providing a direct link between the observed morphology and sequence data. The morphology of the novel Connecticut Didymosphenia taxon was compared with that of other Didymosphenia taxa, being most similar to D. pumila, D. laticollis, D. grunowii and smaller cells of D. geminata. Didymosphenia sp. had a triundulate morphology with a consistent length of 40–60 µm. Given the unique morphological features of this diatom, it is proposed as a new species, Didymosphenia hullii Khan-Bureau, sp. nov.
Current taxonomic studies on the diatom flora (Bacillariophyceae) of the Bolivian Altiplano, South America, with possible consequences for palaeoecological assessments
(Copernicus Publications, 2014) Eduardo A. Morales; Carlos E. Wetzel; Sinziana F. Rivera; Bart Van de Vijver; Luc Éctor
Abstract. The present investigation is based on detailed taxonomical analyses combining light microscopy (LM), scanning electron microscopy (SEM) and critical reviews of publications and type material. This method revealed a higher number of diatom taxa than that reported for the Altiplano, reports that are based on LM and SEM, but force-fitting the taxa into their European relatives. It also became evident that some taxa often reported from the Altiplano do not occur or are less common in this region and that misidentifications are the consequence not only of force-fitting, but also of misinterpretation of the original protologues and illustrations (taxonomic concept drift). These findings have important repercussions on past palaeoecological assessments for the Altiplano, which have been based on ecological information for taxa developing in ecosystems of highly contrasting conditions. Here we present the case of three araphid diatoms, which were reported as known taxa from Europe and elsewhere, but in fact correspond to taxa described as new for the Altiplano or unpublished taxa. It is recommended that: (1) a flora for this region is developed utilizing sound microscopical data and reviewing pertinent type material, (2) key common taxa used for past palaeoecological studies in the Altiplano are reviewed using a taxonomically thorough and critical method, and (3) future palaeoecological studies for the Andes are supported by prior detailed taxonomical analysis.
Diatoms (Bacillariophyceae) from the Bolivian Altiplano: three new araphid species from the Desaguadero River draining Lake Titicaca.
(Česká algologická společnost, 2012) Eduardo A. Morales; María Helena Novais; Gabriela Chávez; Lucien Hoffmann; Luc Éctor
Three new araphid diatom species, Pseudostaurosira decipiens E. Morales, G. Chávez et Ector, P. sajamaensis E. Morales et Ector and Staurosira kjotsunarum E. Morales, Novais et Ector are described from a single sample taken from the Desaguadero River in the Bolivian Altiplano. These species clearly belong in their respective genera as evidenced by their morphological features studied using light (LM) and scanning electron microscopy (SEM). Pseudostaurosira decipiens is unique in its genus because of the combination of lanceolate-shaped valves with central area, well-developed spines lacking ligulae, siliceous deposits on outer and inner areolar openings similar to flaps, and the inner rounded structure of the apical pore fields. Pseudostaurosira sajamaensis is different from other species of Pseudostaurosira due to its elliptic to lanceolate valves bearing a wide central sternum, spines with developed ligulae and bilobed flaps, robust volae and reduced or absent apical pore fields. Staurosira kjotsunarum is unique within Staurosira in having elevated costae on both external and internal views, narrowly spatulate spines that hold onto areolae of neighboring valves along a chain, and striae composed of round poroids underneath the apical pore fields on the valve mantle. The three species are compared with morphologically similar taxa and a brief analysis of the richness found in the studied sample in the context of previous publications on diatoms from the Andes and contiguous regions is presented.
Hipótesis: la agrupación Microcystis aeruginosa Kütz.-Nitzschia palea (Kütz.) W. Sm.-bacterias en la laguna Alalay, Cochabamba, Bolivia es de tipo simbiótico
(2015) Eduardo A. Morales; Sinziana F. Rivera; Carlos E. Wetzel; Paul B. Hamilton; Denise C. Bicudo; Ricardo Amils Pibernat; Luc Éctor
Fragilariforma javanicacomb. nov.: analysis of type material of a widely reported species with a tropical distribution
(Taylor & Francis, 2013) Carlos E. Wetzel; Eduardo A. Morales; Friedel Hinz; Denise C. Bicudo; Luc Éctor
The transfer of Fragilaria javanica Hustedt to the genus Fragilariforma D.M. Williams & Round is presented based on a detailed analysis of the type material from Java (Malay Archipelago) using light and scanning electron microscopy. The taxon is characterized by each areola covered externally with a rota, well-developed, simple apical pore fields composed of rounded poroids and located on both valve apices, denticulate spines with tips oriented towards the apices, and open girdle bands with valvocopulae bearing heavily silicified advalvar fimbriae. These features are all shared with species currently ascribed to Fragilariforma, although the spine shape and orientation, and girdle elements having two rows of areolae, along with valvocopulae with well-developed fimbriae are typical of F. javanica. Morphological, ecological and distribution data are presented and discussed based on available literature for this taxon.
Morphological observations and emended description ofAmphora micrometrafrom the Bolivian Altiplano, South America
(Taylor & Francis, 2011) Éva Ács; Luc Éctor; Keve T. Kiss; Csaba Cserháti; Eduardo A. Morales; Zlatko Levkov
Abstract A population of Amphora micrometra Giffen, collected in September 2002 from different habitats in Laguna Blanca in the Bolivian Altiplano, South America, has been examined using light transmission and scanning electron microscopy. The original description of this species is incomplete and insufficient to characterize the taxon in the light of the newly collected ultrastructural data. The holotype of A. micrometra was examined during the present study and compared to Bolivian specimens. An emended diagnosis of A. micrometra using all available information is provided. A taxonomic discussion based on available literature and the ecology of the taxon is also presented herein. Keywords: BacillariophyceaeAndesBoliviaLaguna Blanca Amphora micrometra taxonomy Acknowledgements The authors thank Johan van der Molen, Curator of CSIR diatom collection (KwaZulu-Natal, Regional office in Durban, South Africa), for M.N. Giffen type slide and raw material of the South African Diatom Collection, Katarina Caput (Department of Molecular Biology, Faculty of Sciences, University of Zagreb, Croatia) for TEM micrographs, Mike Amspoker and an unknown referee for the correction of the manuscript. The 2002 expedition to Bolivia was funded by the NASA Ames Research Center (ARC) Directorate Discretionary Funds and supported by the ARC Space Science Division. The authors thank Nathalie A. Cabrol (Expedition Leader) for the possibility to participate on the expedition and the use of the chemical data presented herein.
Morphological studies on type material of widely cited araphid diatoms (Bacillariophyta)
(Taylor & Francis, 2015) Eduardo A. Morales; Carlos E. Wetzel; Bart Van de Vijver; Luc Éctor
:We analysed syntype material of Odontidium harrisonii W. Smith, Odontidium mutabile W. Smith, Odontidium tabellaria W. Smith, Odontidium tabellaria var. β W. Smith, Odontidium parasiticum W. Smith, Odontidium parasiticum var. β W. Smith and Fragilaria brevistriata Grunow in Van Heurck. A combination of light and scanning electron microscopy revealed that taxonomic drift led to currently misconstrued concepts of many of these taxa. Preservation of type materials allowed morphological study of each taxon in detail. The following new combinations, new names and new statuses are presented: Staurosirella harrisonii (W. Smith) E. Morales & C.E. Wetzel comb. nov., Staurosirella mutabilis (W. Smith) E. Morales & Van de Vijver comb. nov. and Pseudostaurosira smithii E. Morales & Ector nom. nov. stat. nov. Nomenclatural and ecological discussions, based on historical and current literature, are presented for each taxon. The study of type materials is a necessary task in order to improve current databases used for taxonomic and ecological purposes, and such a study should be an essential component of large-scale palaeo or neo-limnological research programs.
New epiphytic araphid diatoms in the genus Ulnaria (Bacillariophyta) from Lake Titicaca, Bolivia
(Taylor & Francis, 2013) Eduardo A. Morales; Sinziana F. Rivera; Carlos E. Wetzel; María Helena Novais; Paul B. Hamilton; Lucien Hoffmann; Luc Éctor
Two new epiphytic species of Ulnaria (Kützing) Compère, U. titicacaensis E. Morales, Ector & P.B. Hamilton and U. macilenta E. Morales, C.E. Wetzel & S.F. Rivera, are described from the Tiquina Strait, Lake Titicaca, Bolivia. The taxa have distinctive morphological features and their separation from morphologically related taxa and from each other is predominantly based on features of the valve central area and type of colonies. Whereas most morphologically similar taxa have a clear unilateral central area and form ribbon-like colonies, U. titicacaensis has a central area which is large and depressed internally, square to rectangular fascia, forms pin-cushion-like colonies mainly on Cladophora species, and has large polyphosphate bodies located toward the frustule apices. In contrast, U. macilenta has a similar central area to that in U. titicacaensis, but has narrower valves, forms short palisade groupings arranged in pin-cushion-like colonies, mainly on Oedogonium species and has polyphosphate bodies distributed throughout the frustule lumen. Morphological and ecological aspects of both new taxa are discussed in the light of available literature.
New species and combinations on Fragilariforma (Bacillariophyta) from tropical freshwater environments
(Česká algologická společnost, 2017) Pryscilla D. Almeida; Carlos E. Wetzel; Eduardo A. Morales; Luc Éctor; Denise C. Bicudo
Several species currently belonging to the genus Fragilariforma D.M. Williams et Round are known worldwide. This genus is mainly characterized by regular spacing of the uniseriate striae composed of round areolae bearing simple vela, and simple apical pore fields. A large number of species has been recognised for some regions of South America and tropical Africa, but few studies encompass type material and/or the morphological variation existing within populations of the different species. The aim of this study is to identify and describe the morphology of these species from tropical environments under light and scanning electron microscopy and using available type material. Nomenclatural issues are examined and clarified for five taxa: Fragilaria nitzschioides var. brasiliensis Grunow, F. undata var. brasiliensis C. Zimmermann, F. strangulata (Zanon) D.M. Williams et Round, F. telum J.R. Carter et Denny and F. rolandschmidtii Metzeltin et Lange-Bertalot. The type material of F. nitzschioides var. brasiliensis, housed in the Grunow Collection at the Naturhistorisches Museum Wien (W) was examined and its epitypification is proposed. One new species from the Amazon region Fragilariforma amazonica sp. nov. is presented and described here, while Fragilaria telum is formally transferred to the genus Fragilariforma.
On the geographical distribution and ecology of Pseudostaurosira cataractarum (Bacillariophyceae): new findings in the Palearctic and Neotropic ecozones
(Springer Science+Business Media, 2015) Lorena Grana; Eduardo A. Morales; Tomáš Bešta; Daniela María Echazú; Carlos E. Wetzel; María Helena Novais; Hana Rajdlová; Luc Éctor; Nora I. Maidana
Taxonomy and ecology of Fragilaria billingsii sp. nov. and analysis of type material of Synedra rumpens var. fusa (Fragilariaceae, Bacillariophyta) from Brazil
(Q15088586, 2016) Simone Wengrat; Eduardo A. Morales; Carlos E. Wetzel; Pryscilla D. Almeida; Luc Éctor; Denise C. Bicudo
Synedra rumpens var. fusa was originally described by Patrick, but there are only a few subsequent records of this variety in the literature. Analysis of samples from Brazilian reservoirs containing a morphologically similar taxon led us to the analysis of the type material of S. rumpens var. fusa, performed using light (LM) and scanning electron microscopy (SEM). In the present manuscript, an amendment to the description of the var. fusa is made and its transfer to the genus Fragilaria as F. fusa comb. et stat. nov. is proposed. Moreover, Fragilaria billingsii sp. nov. is described from a large multipurpose reservoir from the State of São Paulo, Brazil. Comparative discussions with morphologically related taxa found in the literature are presented. Regarding ecological preferences, the new species was found living in slightly acidic and meso-eutrophic waters.
Transfer of Staurosira grunowii to Staurosirella
(Taylor & Francis, 2013) Eduardo A. Morales; Krisztina Buczkó; Carlos E. Wetzel; María Helena Novais; Nadja Ognjanova‐Rumenova; Lucien Hoffmann; Luc Éctor
The new combination Staurosirella grunowii (Pantocsek) E. Morales, Buczkó & Ector comb. nov. is presented based on a detailed analysis of fossil material from Lutila, Slovakia using light and scanning electron microscopy. The species is widely known as Staurosira harrisonii var. amphitetras Grunow. Striae bearing well-developed vimines delimiting typically long areolae, thick virgae-bearing spines, developed apical pore fields composed of simple round poroids and open girdle bands with valvocopula-bearing fimbriae are some of the features that link this taxon to species currently ascribed to Staurosirella D.M. Williams & Round. The taxon is readily distinguished by its tetra-angular shape, which is not seen in any other species within this genus. An analysis of the morphology of this taxon together with its nomenclatural history is presented herein.
Transfer of Fragilaria atomus Hust. to the genus Stauroforma (Bacillariophyta) based on observation of type and newly collected material
(Q15088586, 2014) Dávia Marciana Talgatti; Carlos E. Wetzel; Eduardo A. Morales; Luc Éctor; Lezilda Carvalho Torgan
Fragilaria atomus was described from a brackish water lagoon in southern Finland and has subsequently been reported from several localities worldwide. However, due to its small size, it can be easily mistaken with other small, morphologically similar araphid diatoms. To clarify the morphological, metric and structural features of the species, lectotype material from BRM (Hustedt’s diatom collection) and specimens from salt marshes in Brazil were studied using light and scanning electron microscopy. Fragilaria atomus is compared to seven morphologically similar taxa belonging to Fragilaria, Stauroforma and Psammoneis. The results revealed that some important features of Fragilaria (discoid closing plates, rimoportulae and spines) are not present in F. atomus. The absence of these structures, together with the opposite striation pattern, round areolae, features of the apical pore field, and reduced or absent sternum, suggest that a transfer of F. atomus to Stauroforma is appropriate. The distribution and ecology of F. atomus is discussed.
Two new diatoms in the genus Fragilaria Lyngbye (Fragilariophyceae) from tropical reservoirs in Brazil and comparison with type material of F. tenera
(Q15088586, 2016) Pryscilla D. Almeida; Eduardo A. Morales; Carlos E. Wetzel; Luc Éctor; Denise C. Bicudo
Two new diatom species, Fragilaria neotropica sp. nov. and F. spectra sp. nov., from six reservoirs with different trophic status in the Alto Tietê River Basin, São Paulo, Brazil, are described. Descriptions are based on light (LM) and scanning electron microscopy (SEM) data revealing that both taxa have distinctive features that separate them from each other and from other taxa currently in Fragilaria. Fragilaria neotropica has high stria density, broader (sometimes deformed) central area, and capitate (often deflected) apices. This species was found in high abundance as part of the phytoplankton, periphyton and surface sediments in mesotrophic reservoirs. On the other hand, F. spectra has indistinct striae (not clearly seen in LM), wide sternum, two rimoportulae per valve and lacks spines. This taxon was abundant in the phytoplankton and periphyton of oligotrophic to mesotrophic reservoirs. A discussion of morphological and ecological aspects in the light of available literature is presented, as well as a morphological comparison based on LM and SEM analysis of the original material of F. tenera.
Unraveling the Identity ofFragilaria pinnataEhrenberg andStaurosira pinnataEhrenberg: Research in Progress on a Convoluted Story
(2013) Eduardo A. Morales; José María Guerrero; Carlos E. Wetzel; Silvia E. Sala; Luc Éctor
Fragilaria pinnata Ehrenberg is one of the most commonly reported taxa in floristic and ecological works from around the world. Yet, the images published for this taxon reveal that its identity is not well defined and that several morphological variants have been ascribed to it. The present manuscript includes a preliminary analysis of the literature and type material housed in the Ehrenberg Collection, Berlin, Germany. The nomenclatural history of the taxon, a critical examination of original drawings, and results of the examination of type material lead to the conclusion that Fragilaria pinnata (current synonym: Staurosirella pinnata (Ehrenberg) D.M.Williams & Round) is not an araphid diatom, but rather an organism with links to the genus Denticula Kützing. The history of another taxon, Staurosira pinnata Ehrenberg, was also investigated to determine its actual relationship to Fragilaria pinnata since recent publications present these two names as synonyms. Staurosira pinnata also has an entangled history and a dubious current concept. Although, we have not examined type material for this taxon yet, based on examination of the nomenclatural history and original drawings, we were able to conclude that it is indeed an araphid diatom, but that the current synonymy with Fragilaria pinnata is incorrect.