Cyclostephanos invisitatus (M.H. Hohn & Hellerman) Stoermer, E.C. Ther. & Hak . in Theriot, Stoermer and Hakansson , Diatom Res. 2: 256, figs 10 d-f. 1988.

Bilous, Olena P., Genkal, Sergey I., Zimmermann, Jonas, Kusber, Wolf-Henning & Jahn, Regine, 2021, Centric diatom diversity in the lower part of the Southern Bug river (Ukraine): the transitional zone at Mykolaiv city, PhytoKeys 178, pp. 31-69 : 31

Cyclostephanos invisitatus (M.H. Hohn & Hellerman) Stoermer, E.C. Ther. & Hak. in Theriot, Stoermer and Hakansson, Diatom Res. 2: 256, figs 10 d-f. 1988.

Basionym.

Stephanodiscus invisitatus M.H. Hohn & Hellerman, Trans. Am. Microscop. Soc. 82 (3): 325. 1963.

Morphological description.

Frustule disciform, valve face flat, 9.4-14.5 μm in diameter, multiseriate striae 10-14 in 10 μm, ribs are continuing on curve of the valve, spines grow from every rib (Fig. 7H ).

Ecology.

Cyclostephanos invisitatus was recorded as planktonic species from rivers, ponds, lakes, reservoirs and seas, freshwater, brackish and marine waters. Also known from waters of eutraphentic conditions, moderate and higher trophy and moderate alkalinity ( Krammer and Lange-Bertalot 2000; Siver et al. 2005; Kirilova et al. 2010; Hofmann et al. 2018).

Distribution.

C. invisitatus was found 5 km downstream Mykolaiv city (Table 1 ), and was recorded for this River earlier ( Bilous et al. 2012; Bilous et al. 2014; Belous 2016). In turn, it is common for the Dnipro River and there are some findings in the Danube River ( Tsarenko et al. 2009).

Probably a cosmopolitan species, known from Europe (Germany, Hungary, Poland, Russia), Asia (Armenia, Azerbaijan, Russia), Northern America (USA), Africa (Egypt); Caspian Sea ( Wojtal and Kwandrans 2006; Tsarenko et al. 2009; Kiss et al. 2012; Genkal et al. 2020).

Figures

Figure 7. SEM (A-E, G, H) and LM images (F) of species found in the transitional zone at Mykolaiv city, valve views: A Cyclotella cryptica B Cyclotella marina C, D Cyclotella meduanae E, F Cyclotella meneghiniana G Cyclostephanos dubius H Cyclostephanos invisitatus, with arrows shown on A, D, H marginal and central fultoportulae, B marginal fultoportulae, F central fultoportulae. Scale bars: 2 μm (B, D); 4 μm (A); 5 μm (C, E); 10 μm (F-H).