Browsing by Autor "Sinziana F. Rivera"
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Item type: Item , 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 ÉctorAbstract. 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reported as known taxa from Europe and elsewhere, but in fact correspond to taxa described as new for the Altiplano or unpublished taxa.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.Item type: Item , Floración algal nociva (FAN) producida por cianobacterias en la laguna Alalay, Cochabamba, Bolivia(2017) Eduardo A. Morales; Sinziana F. Rivera; Luis H. Vildozo; Anelisse PolItem type: Item , 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 ÉctorItem type: Item , <i>Aulacoseira kruegeriana</i> (Diatomeae, Coscinodiscophyceae): a new centric diatom from high-elevation Andean rivers and streams of Bolivia(Taylor & Francis, 2015) Eduardo A. Morales; Sinziana F. Rivera; Sergio Rubin; Morgan L. Vis; Václav HoukA new centric diatom, Aulacoseira kruegeriana sp. nov., collected from small streams in the Yungas (cloud forest) region of Bolivia, is described based on light and electron microscopy. The new species is morphologically similar to Aulacoseira principissa Van de Vijver, A. alpigena (Grunow) Krammer, A. ambigua (Grunow) Simonsen, A. gessneri (Hustedt) Simonsen, A. laevissima (Grunow in Van Heurck) Krammer, A. lirata (Ehrenberg) Ross, and A. nygaardii (Camburn) Camburn & D.F. Charles. However, it is distinguished by its finer frustule structure, presence and features of separation and linking spines, density of areolae, rotae as mostly three-point bars, a solid and thick ringleist and indistinctly sigmoid mantle striae. Aulacoseira kruegeriana is the first new species of Aulacoseira. Thwaites reported from Bolivia. However, the literature on centric diatoms in this country is currently scarce and, as more research is conducted on streams and lakes, it is likely that additional novel centric diatoms will be discovered.Item type: Item , Macrófitas poco frecuentes o desconocidas de la laguna Alalay, Cochabamba, Bolivia(2013) Eduardo A. Morales; Sinziana F. RiveraItem type: Item , New epiphytic araphid diatoms in the genus <i>Ulnaria</i> (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 ÉctorTwo 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.Item type: Item , Nuevos taxa de diatomeas (Bacillariophyta) descritos en el Herbario Criptogámico de la Universidad Católica Boliviana San Pablo (HCUCB)(2013) Sinziana F. Rivera; Eduardo A. MoralesItem type: Item , Ocurrencia de Cyclotella meduanae Germain (Bacillariophyta) en la laguna Alalay, un cuerpo de agua salobre y eutrófico (Cochabamba, Bolivia)(2013) Eduardo A. Morales; Sinziana F. Rivera; Rosemary Ayala; Francisca AcostaItem type: Item , Primer reporte confirmado de Hydrodictyon reticulatum (Chlorophyta, Hydrodictyaceae) para Bolivia(2015) Eduardo A. Morales; Sinziana F. Rivera; Reinaldo Lozano; Carlos Eduardo de Mattos BicudoItem type: Item , Publicaciones científicas del Herbario Criptogámico de la Universidad Católica Boliviana San Pablo (HCUCB)(2013) Sinziana F. Rivera; Eduardo A. Morales