Pleurosira laevis (Ehrenb.) Compere in Bacillaria 5: 177, figs 1-17, 20, 39. 1982.

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

Pleurosira laevis (Ehrenb.) Compere in Bacillaria 5: 177, figs 1-17, 20, 39. 1982.

Basionym.

Biddulphia laevis Ehrenb. in Ber. Bekanntm. Verh. Königl. Preuss. Akad. Wiss. Berlin: 122. 1843.

Synonyms.

Cerataulus laevis Ralfs in A. Pritch., C. polymorpha Van Heurck, Odontella polymorpha Kütz.

Morphological description.

The frustule is cylindrical, valves are elliptical-rounded-oval, with diameter 39-61 μm, 15-17 areolae in 10 μm (Fig. 4A-D ).

Ecology.

This taxon occurs in brackish and fresh water habitats, commonly found in estuaries of large rivers, also surviving in inland waters with high conductivity, this is a halophilic species. It has considerable abundance in epiphytic, benthic hard waters with relatively high electrical conductivity. Distributed and more abundant in warm-temperate and tropical waters, being mesohalobic, from alkalibiontic to alkaliphilic indicator, β-mesosaprobic, and eutraphentic ( El-Awamri 2008).

Distribution.

Valves were found in benthic samples in the Mykolaiv city of the Southern Bug River and downriver (Table 1 ). For Ukrainian territory it was recorded for estuaries of the Black Sea, also reported for the Southern Bug River ( Tsarenko et al. 2009).

Pleurosira laevis is quite cosmopolitan, distributed in the Boreal, near coasts of Europe (Czech Republic, Finland, Germany, Romania, Russia, Sweden, Ukraine), Asia (Korea, Turkey), South America (Brazil), Africa (Egypt), Hawaiian Islands; Azov, Black and Marmora Seas ( Tsarenko et al. 2009; Park et al. 2017b). For Europe this taxon is considered an invasive species ( Handbook of alien species in Europe DAISIE 2009). An upstream colonisation of Pleurosira laevis with help of different vectors for the River Labe was discussed by Fránková-Kozáková et al. (2007).

Figures

Figure 4. SEM (A, B and E-H) and LM (C, D) images of species found in the transitional zone at Mykolaiv city: A-D Pleurosira laevis A, C valve views with arrows shown the ocelli B girdle view E Conticribra weissflogii, valve view with arrows shown central and marginal fultoportulae F Thalassiosira incerta, valve view with arrow shown central fultoportulae G Thalassiosira faurii, valve view H Minidiscus proschkinae, valve view with arrow in the centre shown central fultoportula, and closer to the edge - rimoportula. Scale bars: 10 μm (C-G); 30 μm (A); 50 μm (B); 3 μm (H).