Eunotia incisa W. Smith ex Gregory, 1854: p. 96, pl. 4/fig. 4. *

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 : 11

Eunotia incisa W. Smith ex Gregory, 1854: p. 96, pl. 4/fig. 4. * Figs 21-23

Lectotype.

Eunotia incisa W. Smith ex Gregory, 1854: pl. 4/fig. 4. (= Fig. 22 here), designated here.

Illustrations.

Krammer and Lange-Bertalot 1991: p. 221, pl. 161/figs 8-19, pl. 162/figs 1-2 (SEM), pl. 163/figs 1-7; Ohtsuka 2002: fig. 62; Ortiz-Lerín and Cambra 2007: p. 424, figs 5/O-R, 6/C, K; Taylor et al. 2007: pl. 20/5 exemplars; Furey 2011: 7 exemplars and 2 (SEM); Bąk et al. 2012: p. 134, pl. 16/8 exemplars; Ector et al. 2015: p. 254-256, 25 exemplars; Costa 2015: p. 55, pl. 22/figs 1-21, pl. 23/figs 1-5 (SEM); Bahls et al. 2018: pl. 23/figs 19-28, pl. 40/figs 2,3; pl. 87/figs 11, 12; pl. 112/figs 17-19.

Diagnosis.

Morphometric data: length 17-27 µm, width 3.5-4.0 µm, striae density 19-22 in 10 µm. Costa 2015: length 18-43 µm, width 3.0-4.5 µm, striae density 18-21 in 10 µm.

Frustule bi-symmetric, bipolar, biraphid with mirror-symmetric, mantle-offset, brevisslit type of raphe, in girdle view rectangular. Valves dorsiventral with convex dorsal, straight ventral margins and gradually contracted acutely rounded poles turned to ventral valve side. Dorsal mantle arcuate with uninterrupted striae; ventral mantle abruptly perpendicular to the valve surface, hyaline, its height is about 0,5 of valve width (see Costa 2015: pl. 23/figs 1, 3, 5). Striae basal, uniserial, distant, gradually compacted from valve center to the poles (see Costa 2015: pl. 23/fig. 1). Areolae small with round outer foramina. Raphe system consists of two short filiform arcuate slits on hyaline area of ventral valve mantle, on external valve surface distal ends of the slits finish by distant from the poles round funnels on valve/mantle junction; central raphe pores are funnel-like; tr-fissures absent. One apical rimoportula has round external opening (see Costa 2015: pl. 23/figs 3, 5).

Ecology.

Freshwater benthic species occurs in upland streams in acidic, xeno-oligosaprobic waters with poor electrolytes content ( Ortiz-Lerín and Cambra 2007, Taylor et al. 2007). In rivers and streams of Northern Spain has been recorded highest abundance between 7-10% in conditions with pH 5.3-6, conductivity 38-51 μS /cm, altitude 472-484 m asl, SPI 19.3-19.7 ( Ortiz-Lerín and Cambra 2007). The species was found both in oligo- and eutrophic waters: total phosphorus <71.4 mg/cm3, conductivity 13-142 μS /cm and pH 5.3-9.3. High abundances of E. incisa reported from eutrophic conditions are in disagreement with other literature data ( Costa 2015).

Distribution.

EUROPE: Baltic Sea, Belgium, Britain, Czech Republic, Finland, France, Germany, Ireland, Italy, Macedonia, Netherlands, Poland, Romania, Russia, Spain (M. Gury in Guiry and Guiry 2019); Ukraine (present paper). N. AMERICA: USA, Canada (M. Gury in Guiry and Guiry 2019). S. AMERICA: Brazil, Colombia. AFRICA: South Africa ( Taylor et al. 2007); Ghana, Sudan (M. Gury in Guiry and Guiry 2019). ASIA: India, Israel; Bering Island, Korea, Russia, Singapore (M. Gury in Guiry and Guiry 2019); Japan ( Ohtsuka 2002). AUSTRALIA: New Zealand, Australia (M. Gury in Guiry and Guiry 2019). In Ukraine. The Cheremsky Nature Reserve, tract Obkopane, Lake Redychi, epiphyton on Fontinalis sp.

Comments.

Distal ends of the raphe slits are clearly visible on the valve/mantle ridge in LM photos, which is a valuable character in species identification.

Figures

Figures 13 - 27. New and rare in Ukraine species of Eunotia Ehrenb. from Ukrainian Polissya and the Lectotypes of two Eunotia species. 13, 13 a Eunotia pseudoflexuosa Hust., arrow indicates rimoportula at the middle of pole where raphe slit distal end finishes on the outer valve surface, double arrow - position of terminal fissure distal end on the outer valve surface, between the arrows - hyaline field from inside valve surface where the terminal fissure is located on the outer valve surface 14 Eunotia ruzickae Bily & Marvan 15, 16 Eunotia implicata Noerpel-Schempp et al. Lectotype: 15 = Eunotia impressa var. angusta Grunow in Van Heurck 1881: pl. 33 / fig. 22, designated here 17, 17 a Eunotia sp. 2 (Eunotia cf. mongolica Kulikovskiy et al.) 18 - 20 Eunotia sp. 3 (cf. Eunotia paludosa Grunow) 21 - 23 Eunotia incisa W. Smith ex Gregory. Lectotype: 23 = Eunotia incisa W. Smith ex Gregory 1854: pl. 4 / fig. 4, designated here 24 Eunotia sp. 4 (cf. Eunotia intermedia (Krasske ex Hustedt) Noerpel & Lange-Bert.) 25 - 27 Eunotia sp. 5 (cf. Eunotia meridiana Metzeltin & Lange-Bert.). Figs 13, 17, 18 SEM: 13, 13 a inside valve surface 17, 17 a, 18 outside valve surface; 19 - 28 LM. Scale bars: 10 µm (13 - 17, 19 - 27); 5 µm (18); 1 µm (13 a, 17 a).