Observation on Achnanthes Bory sensu stricto (Bacillariophyceae) from subaerial habitats in Macedonia and comparison with the type material of A. coarctata (Brébisson ex W. Smith) Grunow, A. coarctata var. sinaensis Hustedt and A. intermedia Kützing.

Abstract

Four species of Achnanthes sensu stricto have been observed in several subaerial habitats/localities in Macedonia. The morphological features of all recorded species have been described based on light and scanning electron microscope observations. Two species posses similar morphological features as already described species and were identified as A. coarctata (BréBisson ex W. smiTh) GrunoW and A. sinaensis (husTedT) stat. nov. Two species have unique set of characters that separate them from the known species and are described in this study as A. pseudocoarctata levkov et Tofilovska sp. nov. and A. prominula levkov et Tofilovska sp. nov. All recorded species were compared with the type populations including A. coarctata, A. coarctata var. sinaensis husTedT, and A. intermedia küTzinG. Observations of the syntype populations of A. coarctata give precise frame of the morphological variability of the species. Achnanthes pseudocoarctata appears similar to A. coarctata, but can be easily differentiated by the morphological and ultrastructural features of the rapheless valve. Achnanthes coarctata var. sinaensis has distinct morphological characters that make clear separation from A. coarctata, and therefore we propose a new status of this taxon with raising its rank to a species level. Achnanthes prominula appears similar to A. intermedia, but from latter can be easily separated by the position of the rapheless sternum. From other species with lanceolate or elliptic-lanceolate valves, A. prominula can be differentiated by the valve shape, position of the rapheless sternum, central area, stria and areola density.

Diatom flora in subterranean ecosystems: a review

“…In particular, Achnanthes perfida J.R. Carter, Brachysira vitrea (Grunow) Van de Vijver et al, 2002b;Buczkó, 2003;Kopalová et al, 2009;Lowe et al, 2014), but also for the genera Achnanthes (Tofilovska et al, 2014) and Luticola (Kopalová et al, 2011;Levkov et al, 2013), it is important to consider that modern techniques for the morphological analyses, such as SEM, were not available and spread during the first half of the 20 th century. Fine structures in very small specimens, nowadays considered as systematic character for the determination of diatoms at species level, have not been observed during most of the researches included in this review.…”

Four new monoraphid diatom species (Bacillariophyta, Achnanthaceae) from the Maritime Antarctic Region

“…Achnanthes sinaensis (Hust.) Levkov et al (Tofilovska et al 2014) shows a comparable valve outline, although the valve middle is slightly more tumid (Tofilovska et al 2014) and the apices are weakly protracted and more truncated and less broadly rounded, compared to A. kohleriana sp. nov.…”

“…nov. Internally the central area is clearly panduriform and elevated from the rest of the valve (Blunn & Evans 1981, fig. 4 (Tofilovska et al 2014), a recently described species from Osogovo, Macedonia, differs in having lanceolate or elliptic-lanceolate valves with narrowly rounded apices (and not linear to linear-elliptic valves with rounded apices), and with slightly coarser striation of 12-13 striae in 10 µm with only 5 areolae per stria (Tofilovska et al 2014), opposite to A. kohleriana sp. nov. where the number of the striae in 10 µm does not exceed 12.…”

“…Recently Tofilovska et al (2014) revised the type material of A. coarctata (Bréb.) Grunow in Cleve & Grunow (Cleve & Grunow 1880) and some of its varieties.…”

“…nov. The marginal ridge in A. sinaensis is more developed (see for instance Tofilovska et al 2014, fig. 13c).…”