Hantzschia zikmundiana, Bulínová & Kochman-Kędziora & Kopalová & Vijver, 2018

Bulínová, Marie, Kochman-Kędziora, Natalia, Kopalová, Kateřina & Vijver, Bart Van De, 2018, Three new Hantzschia species (Bacillariophyta) from the Maritime Antarctic Region, Phytotaxa 371 (3), pp. 168-184 : 173

Hantzschia zikmundiana sp. nov. ( Figs 22–34 )

LM ( Figs 22–30 ):—Valves clearly dorsiventral with a very convex dorsal side. Ventral side deeply concave in the middle becoming more convex towards the apices. Valve apices protracted, capitate, distinctly deflected towards the dorsal side. Valve dimensions (n=25): length 37.5–45.0 μm, width 7.0–8.5 μm. Fibulae, 6–9 in 10 μm, the middle two fibulae visibly distant from each other. Each fibula connected to 1–3 transapical costae. Striae almost parallel throughout the entire valve, equidistant, 19–22 in 10 μm, towards the apices, becoming slightly curved. In the middle a few (2–4) striae slightly to clearly radiate, more distant than the other striae. Areolae not discernible in LM. SEM ( Figs 31–34 ): Valves on the ventral side bordered by a slightly raised keel ( Figs 31, 32 ). Striae located in shallow grooves bordered by raised costae ( Fig. 32 ). Grooves irregularly interrupted near the ventral margin. Mantle striae located in similar grooves, one areola clearly being separated from the mantle striae ( Fig. 32 ). External areola openings rounded occluded by individual hymenes ( Fig. 32 ) External proximal raphe branches straight, clearly interrupted near the valve middle ( Fig. 32 ). Fibulae not equidistant, the middle clearly more separated than the others ( Fig. 34 ), each of them connected to 1–3 transapical costae. Internal proximal raphe endings weakly deflected, clearly interrupted by a raised central nodule ( Fig. 33 ).

Type:— VEGA ISLAND, sample VEG-M2 (63°48’55.4”S / 57°18’35.6”W), leg. J. Kavan, coll. date 17 January 2013 (holotype, slide BR 4514 ; isotype, slide PLP –344, University of Antwerp , Belgium) .

Ecology:—So far Hantzschia zikmundiana was found in only one sample taken from a very dry moss vegetation around the stream going along the moraine. The sample was dominated by Chamaepinnularia krookiformis ( Krammer 1992: 79–80) Lange-Bertalot & Krammer (in Lange-Bertalot & Genkal 1999: 37) and Pinnularia borealis Ehrenberg (1843: 420) sensu lato. Due to confusion with H. abundans , the exact distribution and ecology of this species is not entirely known.

Etymology:—The species is named after Ing. Miroslav Zikmund (°1919), a famous Czech traveller, author, filmmaker and photographer.

Figures

FIGURES 22–34. Hantzschia zikmundiana. LM and SEM observations of the type population (Vega Island, sample VEGA-M2). Figs 22–30. Light micrographs showing a reduction in valve length. Fig. 31. External view of an entire valve showing the narrow ventral hyaline border and the shallow grooves with the rounded areolae. Fig. 32. External detail of the central area with the straight, interrupted, proximal raphe endings. Fig. 33. Internal detail of the central area with the interrupted proximal raphe endings. Fig. 34. Internal view of an entire valve showing the irregularly placed fibulae. Scale bar represents 10 μm except for figs 32 & 33 where scale bar = 1 μm.