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).