Discostella taxa (Bacillariophyta) from the Río Limay basin (northwestern Patagonia, Argentina)

Abstract

Discostella stelligera and allied similar taxa are mainly identified by the presence of marginal fultoportulae located at the end of the striae, and not on the interstriae, as occurs in the genus Cyclotella, from which they have recently been removed. In this paper, valve morphology and ultrastructure of D. stelligera, D. glomerata, D. pseudostelligera and D. woltereckii collected from different environments within the Río Limay basin are described and illustrated. Morphological characters that allow the delimitation of taxa within the group are discussed and the ultrastructure of D. stelligera var. elliptica comb. nov. is shown for the first time. Two organisms that possess distinct morphological characters, and might be considered new species, are described. © 2006 British Phycological Society.