Cymbella balkii C.N.Solak, S.Blanco & N.Balkis-Ozdelice, 2021

Solak, Cüneyt Nadir, Balkis-Ozdelice, Neslihan, Yilmaz, Elif, Durmus, Turgay & Blanco, Saúl, 2021, Description of two new Cymbella (Bacillariophyta) species from Sakarbaşı spring, Turkey, Phytotaxa 484 (2), pp. 195-206 : 197-199

Cymbella balkii C.N.Solak, S.Blanco & N.Balkis-Ozdelice , sp. nov. ( Figs 2–15 )

Description: Valves moderately dorsiventral, lanceolate, dorsal margin moderately arched, ventral margin straight or very slightly convex. Ends not protracted and bluntly rounded. Length 51.3–83.2 μm, breadth 11.0–13.2 μm, maximal length/breadth ratio 6.4 (n=46). Axial area moderately narrow, linear or slightly tapering towards the ends, both branches form an obtuse angle to each other. Central area slightly distinct on the dorsal side, more pronounced on the ventral side. Raphe not or only slightly ventrally displaced, distinctly to strongly lateral, becoming filiform near the distal and reverse-lateral near the proximal ends. Striae moderately to strongly radiate, becoming more radiate near the ends, distinctly, however very finely punctate. Commonly 4, sometimes also 3–5 isolated stigmata on the ventral side of the central nodule. In the SEM, 3–6 large elliptical stigma foramina and 1–4 smaller round stigma foramina. The small round pore foramina are arranged irregularly. Parallel arranged pore field alveoli only on the valve end. The margins of the stigma alveoli are provided with teeth-like structures. Striae in the middle 8–9/10 μm (dorsal) and 10–12 (ventral), becoming up to 14/10 μm towards the ends, puncta 24–28/10 μm.

Type:— TURKEY, Sakarbaşı, Eskişehir ( GPS 39°21’10.04’’N, 31°03’33.24’’E), 872 m a.s.l., collector: Cüneyt Nadir Solak 24.11.2019. Holotype: slide number 27354 (holotype designated here on Fig. 1 ) in the collection of Andrzej Witkowski the University of Szczecin.

Isotype:— Slide no. TR_ ESK _Sakarbası_ Nov2019 _EPF deposited at Kütahya Dumlupınar University ( Turkey) .

Etymology:— The species was dedicated to scuba diver Mr. Erkan BALK who helped to collect the samples.

Differential diagnosis:— Cymbella simonsenii Krammer in Krammer & Lange-Bertalot (1985: 33), C. pervarians Krammer (2002: 58) , C. percymbiformis Krammer (2002: 75) , C. vulgata Krammer (2002: 55) , C. alpestris Krammer (2002: 52) and C. perparva Krammer (2002: 38) are similar taxa.Among them, Cymbella simonsenii and C. pervarians are the most similar taxa with similar outline and ending. However, C. simonsenii and C. percymbiformis (> 14.0 µm) are wider while, C. pervarians is narrower than C. balkii (8.0–12.6 µm and 11.0–13.2 µm respectively). C. balkii has higher stigmata number (3–6) than C. pervarians and C. vulgata (1 isolated stigma on the ventral side). Striae density is higher than C. alpestris (<8) and also, bigger than C. vulgata and C. perparva (> 50 µm).

Distribution:— Observed only in the type locality.

Ecology:— The water temperature ranged from 21.4–22.9 oC, pH was 7.8–7.9, dissolved oxygen (DO) was 5.2– 6.1 mg /L and electrolytic conductivity was 545–575 µS/ cm-1.

Associated diatom flora:— Cymbella cymbiformis (21.2%), Encyonopsis minuta Krammer & E.Reichardt in Krammer (1997: 95) (10.5%), Amphora pediculus (Kützing) Grunow [described as Cymbella pediculus Kützing (1844: 80) ] (5.3%), Navicula cryptotenella Lange-Bertalot in Krammer & Lange-Bertalot (1985: 62) (4.1%), Eunotia arcubus Nörpel & Lange-Bertalot in Lange-Bertalot (1993: 24) (3.8%), Nitzschia gracilis Hantzsch (1860: 40) (2.9%), Staurosira construens Ehrenberg (1843: 424) (2.5%), Pseudostaurosira brevistriata (Grunow) D.M. Williams & Round (1988: 276) (2.2%), Staurosirella pinnata (Ehrenberg) D.M. Williams & Round (1988: 274) (1.9%), unidentified species of Achnanthidium Kützing , Brachysira Kützing , Cocconeis Ehrenberg , Pseudostaurosira D.M.Williams & Round and Sellaphora Kützing were the most frequent taxa in the sample.

Figures

FIGURE 1. Map of study area

FIGURE 2–7. Light micrographs of Cymbella balkii sp. nov. Scale bar = 10 µm.

FIGURE 8–15. SEM micrographs of Cymbella balkii sp. nov. 8. External view of entire valve, 9. External view of central area, 10. External view of valve apex showing apical pore field. 11. External view of valve center showing striae composed of slit-like areolae, becoming round close to axial area, varied shapes of stigmata and the proximal raphe endings, 12. Internal view of entire valve. 13. Internal view of valve central area, 14. Internal view of valve ends with dorsally curved, knob-like helictoglossae, apical pore field and uniseriate striae, 15. Internal view of valve centre showing internal stigma openings. Scale bars 20 µm (Figs 8, 12), 5 µm (Figs 9, 13); 4 µm (Figs 10, 11, 15); 3 µm (Fig 14).