Current taxonomic studies on the diatom flora (Bacillariophyceae) of the Bolivian Altiplano, South America, with possible consequences for palaeoecological assessments

Eduardo A Morales,Bart Van De Vijver,Carlos E Wetzel,Luc Ector,Sinziana F Rivera

doi:10.1144/jmpaleo2014-007

Abstract

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reported as known taxa from Europe and elsewhere, but in fact correspond to taxa described as new for the Altiplano or unpublished taxa.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.

Highlights

Montagne (1839) made the first identifications of diatoms from Bolivia from material collected from the Pacific coast by Alcide d’Orbigny
In the case of Fragilaria elliptica, isotype material found at the Academy of Natural Sciences of Drexel University, in the form of a permanent slide labelled ANSP G.C. 11994 (Pl. 1, figs 6–8 ) and raw material were analysed (SEM results are shown in Pl. 1, figs 5 and 9 ); the original sample was collected by Schumann from Königsberg, Prussia (Schumann, 1867)
The examination of type material of Fragilaria brevistriata (Pl. 1, figs 1–4) shows that none of the variants reported from the Bolivian Altiplano belong to this taxon sensu stricto

Summary

Introduction

Montagne (1839) made the first identifications of diatoms from Bolivia from material collected from the Pacific coast by Alcide d’Orbigny. From the subsequent publications of Ehrenberg (1854a, b) to the most recent article by Morales et al (2012), only 19 taxonomic publications have appeared in the literature for Bolivian diatoms These references are concentrated on the Altiplano area and the great majority deals with palaeoecological assessments on a few ecosystems that are unrepresentative even for this part of the country (see list of publications and discussion in Morales et al, 2008). The recent major taxonomical study of Andean diatoms produced by Rumrich et al (2000) reported a low number of new species and a surprising high number of common elements (42% of 888 recorded taxa) with the European diatom flora (see discussion in Morales et al, 2012) These data are paradoxical for a country counted among those with the highest biological diversity in the world (Ibisch & Mérida, 2003). These data are paradoxical for a country counted among those with the highest biological diversity in the world (Ibisch & Mérida, 2003). Manguin (1964) expressed a similar view of predominant cosmopolitism based on samples from the Andes near Lima, Peru (ranked higher than Bolivia as a biodiverse country), reporting the presence of 52.5% of cosmopolitan taxa out of a total of 392 from 10 samples; at least two of these samples were from below 2000 m above sea level (asl), indicating that they were not truly Altiplanic localities

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Discussion

Conclusion