Browsing by Autor "Denise C. Bicudo"

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Ecology and distribution of<i>Aulacoseira</i>species (Bacillariophyta) in tropical reservoirs from Brazil
(Taylor & Francis, 2016) Denise C. Bicudo; Priscila Izabel Tremarin; Pryscilla D. Almeida; Stéfano Zorzal‐Almeida; Simone Wengrat; Samantha B Faustino; Lívia F. Costa; Elaine Cristina Rodrigues Bartozek; Angélica Cristina Righetti da Rocha; Carlos Eduardo de Mattos Bicudo
Ecological preferences and distribution of Aulacoseira species in southeastern Brazilian reservoirs with varying trophic states were studied. One hundred and fourteen plankton samples (winter and summer) from 57 sites located in 16 reservoirs were analysed. Ten water quality parameters were measured. Ten Aulacoseira species were identified using light, scanning and transmission electron microscopy, and new information on their ecological preferences is provided here. Our results indicate that trophic gradient is the main driver of species distribution. Principal components analysis and calculation of weighted average nutrient optima revealed three indicator taxa, Aulacoseira tenella characteristic for oligotrophic waters and two varieties of Aulacoseira granulata (nominate and var. angustissima) typical for eutrophic reservoirs. This is the first ecological study of Aulacoseira in Brazil, adding information on the distribution of this genus in the tropics, and highlighting the need for species-level identification and regional studies to improve the use of diatoms in water quality assessment.
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
<i>Fragilariforma javanica</i>comb. 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.
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.
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.
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.