Cyclotella choctawhatcheeana A.K.S. Prasad., 1990; emend. Genkal. Biol. vnutr. vod. 2: 1-10. 2012.

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

Cyclotella choctawhatcheeana A.K.S. Prasad., 1990; emend. Genkal. Biol. vnutr. vod. 2: 1-10. 2012.

Synonym.

Cyclotella hakanssoniae Wendker, Nova Hedwigia 52: 360. 1991.

Morphological description.

Frustule low-cylindrical, central part of valve tangentially undulated, valves 9.1-12.3 μm in diameter, 12-14 striae in 10 μm, 1-4 central fultoportulae, 6 marginal fultoportulae in 10 μm (Fig. 6G ).

Ecology.

Cyclotella choctawhatcheeana is a small centric diatom from the plankton of water bodies tolerating a wide temperature range. Originally this species was described as a marine species in the northern Gulf Coast of Florida; it is also recorded from several localities in Florida Bay and its global distribution is discussed ( Prasad et al. 1990). For Germany, it was described from the River Schlei close to the Baltic Sea ( Wendker 1991). Nowadays, it may be classified as an invasive species in brackish waters ( Kiss et al. 2012). This species may grow in different seasons and with high and low nutrient availability ( Oliva et al. 2008). In turn, some authors note that the existence of this species has a positive linear relationship with nutrient concentration ( Jaanus et al. 2009).

Distribution.

It was recorded for the first time in Ukraine in our previous investigation near Mykolaiv city of the Southern Bug River and this study confirms its existence in Mykovaiv city and at the downriver sites (Table 1 ).

Cyclotella choctawhatcheeana was recorded as a cosmopolitan species. Its presence has been confirmed in different localities around the world in brackish waters and rivers connected with saline lakes ( Prasad et al. 1990). It was found as a component of the phytoplankton in the saline Mexican lake Alchichica ( Oliva et al. 2008), in the Baltic Sea, with salinity between 3 and 11‰ ( Wendker 1991; Håkansson et al. 1993), and the Salton Sea, with a salinity in excess of 40‰ ( Lange and Tiffany 2002). Additionally, it is known from saline lakes in North America and Africa ( Carvalho et al. 1995), reservoirs in Russia ( Genkal et al. 2020).

Figures

Figure 6. SEM (A-F, H) and LM images (G) of species found in the transitional zone at Mykolaiv city, valve views: A Stephanodiscus minutulus with arrows shown marginal and central fultoportulae B, C Cyclotella atomus var. atomus with arrows shown marginal and central fultoportulae D-F Cyclotella atomus var. gracilis with arrows shown marginal and central fultoportulae on D picture, only central fultoportula on E and central fultoportula and alveolae on (F) G Cyclotella choctawhatcheeana with arrow shown central fultoportulae H Cyclotella cryptica with arrows shown marginal and central fultoportulae. Scale bars: 3 μm (B, C); 4 μm (D, F); 5 μm (A, E, H); 10 μm (G).