Sellaphora pseudoventralis (Hustedt) Chudaev et Gololobova, 2015

Chudaev, Dmitry A. & Gololobova, Maria A., 2015, Sellaphora smirnovii (Bacillariophyta, Sellaphoraceae), a new small-celled species from Lake Glubokoe, European Russia, together with transfer of Navicula pseudoventralis to the genus Sellaphora, Phytotaxa 226 (3), pp. 253-260 : 254

Sellaphora pseudoventralis (Hustedt) Chudaev et Gololobova , comb. nov. ( Figs 17–29 )

Basionym: Navicula pseudoventralis Hustedt, Archiv für Hydrobiologie 47 (4): 631, figs 12, 13. 1953.

Valves elliptic with protracted and bluntly rounded apices; length 9.1–13.1 μm, width 4.0–5.3 μm. Axial area narrow and linear, not bordered by longitudinal furrows on the external valve surface. Central area transapically widened, varying in width and shape, bordered by irregularly shortened striae. Striae biseriate, sometimes becoming uniseriate around the central area, slightly radiate throughout, 17–20 in 10 μm. Areolae small, round, in staggered rows, 70–81 in 10 μm, internally closed by hymenes. Sometimes linear, apically elongated areolae present at the valve face-mantle junction. Raphe filiform, external proximal endings are unilaterally deflected pores, external distal endings are long fissures deflected to the same side in opposite direction to central pores. Internal central raphe endings slightly deflected to the same side. The distal raphe ends are small narrow helictoglossae.

Distribution and ecology:— In Lake Glubokoe, S. pseudovenralis was found in epiphyton on different macrophytes ( Elodea canadensis Michx. , Menyanthes trifoliata L., Nuphar lutea (L.) Smith, Nymphaea candida J. et C. Presl, Polygonum amphibium L., Potamogeton praelongus Wulf , Sagittaria sagittifolia L., Sparganium sp. ), surface sediments and cores at depths up to 490 cm from bottom surface. The taxon is probably cosmopolitan; it is known as Navicula pseudoventralis from Europe, North and South America, Australia and New Zealand ( Krammer & Lange-Bertalot 1997, Guiry & Guiry 2015). It is common in oligo- to mesotrophic lakes with variable electrolyte content ( Krammer & Lange-Bertalot 1997).

Figures

FIGURES 17–29. Sellaphora pseudoventralis comb. nov. 17–27. Light microscopy. 29–29. SEM. 28. External valve view. 29. Internal valve view. Scale bars: 10 μm (Figs 17–27), 2 μm (Figs 28–29).