Browsing by Autor "Bart Van de Vijver"

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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reported as known taxa from Europe and elsewhere, but in fact correspond to taxa described as new for the Altiplano or unpublished taxa.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.
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.
Three new araphid diatoms (Bacillariophyta) from the Maritime Antarctic Region
(Q15088586, 2014) Bart Van de Vijver; Eduardo A. Morales; Kateřina Kopalová
A revision of taxa from the genus Staurosira and Staurosirella from the Maritime Antarctic Region, formerly identified as Staurosirella (Fragilaria) pinnata and Fragilaria alpestris, resulted in the description of three new taxa: Staurosira pottiezii Van de Vijver sp. nov., Staurosirella antarctica Van de Vijver & E.Morales sp. nov. and S. frigida Van de Vijver & E.Morales sp. nov. Detailed light (LM) and scanning electron microscope (SEM) observations are used to better characterize the morphology and ultrastructure of these three new taxa. Comparisons with similar taxa and the ecological preferences of each species are added. The revision of these species confirmed the endemic nature of the Antarctic diatom flora.