FIGURES 390–394. SEM micrographs of Achnanthidium pseudolineare Van de Vijver, Novais & Ector from Covas, Coura River, Minho basin, 21–09–2007 (224/07). 390. Detail of the apex of a raphe valve in external view, with the straight distal raphe ending. 391. Detail of the central area of a raphe valve in external view, bordered by spaced shorter striae formed by transapically elongated areolae, and the straight, not expanded, proximal pores. 392. Detail of the apex of a raphe valve in internal view, with the raphe ending in a small helictoglossa. 393. Detail of the apex of a rapheless valve in internal view. 394. Complete frustule in girdle view, with the slit-like areolae on the mantle. Scale bars = 1 μm.

Published as part of Novais, Maria Helena, Jüttner, Ingrid, Vijver, Bart Van De, Morais, Maria Manuela, Hoffmann, Lucien & Ector, Luc, 2015, Morphological variability within the Achnanthidium minutissimum species complex (Bacillariophyta): comparison between the type material of Achnanthes minutissima and related taxa, and new freshwater Achnanthidium species from Portugal, pp. 101-139 in Phytotaxa 224 (2) on page 126, DOI: 10.11646/phytotaxa.224.2.1, http://zenodo.org/record/13636829