Four new <i>Aulacoseira</i> species (Coscinodiscophyceae) from Matogrossense Pantanal, Brazil

Abstract

Examination of samples from two lakes in the Matogrossense Pantanal, midwest Brazil, revealed the presence of four new Aulacoseira species, A. minuscula Tremarin, Torgan & T. Ludwig, A. pantanalensis Tremarin, Torgan & T. Ludwig, A. samariana Tremarin, Torgan & T. Ludwig and A. simoniae Tremarin, Torgan & T. Ludwig. These are described and illustrated using light and scanning electron microscopy, and compared with similar species. The new species have low valve mantles, straight pervalvar rows of areolae, narrow ringleists and sessile rimoportulae.