Nitzschia alpinobacillum Lange-Bertalot, 1993

Olszynski, Rafal M., Zakrzewski, Piotr K., Rimet, Frederic, Sulkowska, Julia, Peszek, Lukasz & Zelazna-Wieczorek, Joanna, 2024, Morphology and phylogeny of Nitzschia nandorii sp. nov. (Bacillariophyceae), a new small-celled lanceolate species from a post-mining reservoir, PhytoKeys 241, pp. 1-26 : 1

Nitzschia alpinobacillum Lange-Bertalot, 1993

Notes.

The outline of the frustules is lanceolate, distended with capitate to acutely rounded apices (Fig. 3AX-BI). Valves are 15-22 µm length and 3.0-4.0 µm in width. The ratio of length and width is 4.21-6.41. Striae 23-25 in 10 µm visible in LM. Fibulae are visible 10-14 in 10 µm. Striae are uniseriate, arranged transapically. Areolae are covered by the hymenes. Along the edge of the valve, where the raised raphe canal is located, two longitudinal rows of areolae are present - a doublet nearer to the raphe opened to the interior of the raphe canal and a single areola at the junction with the valve face opened to the valve interior. (Fig. 10A, C-D ). The distal mantle is narrow. Internally, fibulae have equal spacing; there is no wider gap between the centre fibulae (Fig. 10B ). Distal raphe fissures terminate with small helictoglossa (Fig. 10D ).

Figures

Figure 10. SEM photomicrographs of Nitzschia alpinobacillum A external view of the valve, two rows of areolae on the raphe canal, single and doubled areolae, covered by hymenes (white arrow), distal raphe fissure strongly deflected and extends on the proximal mantle B internal view of the valve, there is no wider extension between central fibulae C, D internal view of the apices C areolae on the proximal mantle are arranged the same as on the raphe canal: single and double areolae and covered by hymenes (white arrow), narrow distal mantle (black arrow) D distal raphe fissure terminates with helictoglossa. Scale bars: 5 µm (A-C); 1 µm (D).