New diatom taxa from high-altitude Andean saline lakes

Abstract

During a biological survey carried out in five shallow, high-altitude saline lakes of the Bolivian Altiplano in 2009, six unknown diatom taxa were found in various lake populations. Detailed light and scanning electron microscopy observations allowed the description of the following new taxa: Navicula venetoides (distinguished from N. veneta Kützing by having coarser lineate striae), Pinnularia boliviana (similar to P. rhombarea var. halophila Krammer but with coarser striae and a narrower central area), Nitzschia sansimoni (morphologically close to N. supralitorea Lange-Bertalot, the latter having denser striae), Surirella striatula var. halophila (differing from the nominate and other varieties in a distinctly heteropolar outline and the presence of denser fibulae) and S. moralesii (with large, strictly isopolar valves and a deep pervalvar depression). Differential diagnostic criteria with respect to similar taxa, together with ecological and biogeographical implications of these findings, are briefly discussed.