Browsing by Autor "Carlos E. Wetzel"

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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.
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.
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 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
(2026) Simone Wengrat; Eduardo A. Morales; Carlos E. Wetzel; Pryscilla D. Almeida; Luc Ector; Denise Campos Bicudo
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.