Eunotia genuflexa Noerpel-Schempp in Lange-Bertalot and Metzeltin 1996: p. 50, pl. 9/figs 14-17. *^

Bukhtiyarova, Lyudmila N., 2019, The genus Eunotia Ehrenb. (Bacillariophyta) in the Cheremsky Nature Reserve, Ukrainian Polissya, and refined terminology relevant to the raphe system morphology, PhytoKeys 128, pp. 1-31 : 8

Eunotia genuflexa Noerpel-Schempp in Lange-Bertalot and Metzeltin 1996: p. 50, pl. 9/figs 14-17. *^ Figs 4-6b (SEM)

Eunotia flexuosa f. beta A. Berg, 1939

Eunotioforma genuflexa ( Nörpel-Schemp) Kociolek & Burliga in Burliga et al. 2013

Illustrations.

Bąk et al. 2012: p. 132, pl. 17/1, 2, 5 exemplars from left to right; Kulikovskiy et al. 2016: p. 121, pl. 20/figs 10-14.

Diagnosis.

Morphometric data: length 70-120 µm; width cm2-3, p1.5-2 µm; striae density c20, p23 in 10 µm. Lange-Bertalot and Metzeltin 1996: length 70-160 µm, width 1.5-2.6 µm, striae density 19-23 in 10 µm.

Frustule bi-symmetric, bipolar, biraphid with mirror-symmetric, mantle-offset, brevisslit type of raphe. Valves slightly dorsiventral, with narrowed rounded poles. Striae basal, uniserial, distant, uniformly spaced along the valve (Figs 4a , 5a , 6a, b ). Areolae small with round outer foramina. Raphe system consists of two short filiform slits on ventral valve mantle; tr-fissures long, broadly curved, sited on 0.5 of valve width along 4-5 striae, end up by round lacunae (Figs 4a , 5a , 6a ).

Ecology.

Freshwater benthic species occurs in moderately acidic, dystrophic or oligosaprobic waters. Type location had extremely low concentration of inorganic nutrient and pH = 6.5 ( Lange-Bertalot and Metzeltin 1996).

Distribution.

EUROPE: Type location: Finland, Lake Julma Olkky ( Lange-Bertalot and Metzeltin 1996); Poland ( Bąk et al. 2012); Russia ( Kulikovskiy et al. 2016); Ukraine (present paper). In Ukraine. The Cheremsky Nature Reserve, tract Obkopane, Lake Redychi, epiphyton on Fontinalis sp.

Comments.

Specimens with straight valve outline and subcapitate poles presented in Costa (2015: p. 55, pl. 14/figs 1-11) differ from type population significantly, therefore the author has presented other species under this name. In Bąk et al. (2012) morphology of only three exemplars corresponds to type population.

Type species of the genus Eunotioforma Kociolek & Burliga is Eunotioforma mattogrossiana Kociolek, Burliga & Salomoni ( Burliga et al. 2013) has several characters that differ from the genus Eunotia : axial area on valve surface (= sternum), large heli ctoglossae, different number of rimoportulae (2-8 per valve), small granules along all striae which are not present in E. genuflexa . Strongly curved long tr-fissures are the only common character with a new genus and it can be found in some other species of Eunotia , for instance, E. flexuosa ( Bréb.) Kütz. ( Pavlov and Levkov 2013: pl. 7/fig. 2), E. macedonica Pavlov & Levkov ( Pavlov and Levkov 2013: pl. 10/fig. 2). The only one character is not enough for transferring of E. genuflexa to the genus Eunotioforma .

Figures

Figures 4 - 6 b. New in Ukraine species Eunotia genuflexa Noerpel-Schempp in Lange-Bertalot and Metzeltin, outside valve surface, SEM. Arrows indicate distal ends of raphe slits, double arrows - funnel-like lacunae, terminal fissures are between the arrows. Scale bars: 10 µm (4 - 6); 2 µm (4 a, 5 a, 6 a); 1 µm (6 b).