Hantzschia tokarczukiana M.Rybak, Kochman-Kędziora, sp. nov. (Figs 16–27, 53–60)

LM observations (Figs 16–27): — Valves clearly dorsiventral with convex ventral side, in some specimens almost straight in middle. A dorsal side distinctly concave in middle, but convex near apices. Valve apices clearly protracted, rostrate or sub-capitate. Valve dimensions (n=20): length 33.5–93.0 μm, width 5.5–8.0 μm. Width at widest part of valve face: 6.0–8.0 μm. Unequally spaced fibulae, 5–8 in 10 μm, middle two clearly more distant than others. Striae in middle part of valve slightly radiate, becoming parallel to slightly curved toward apices, 17–20 in 10 μm. Areolae not discernible.

SEM observations (Figs 53–60): — Valves on ventral side bordered by narrow keel (Figs 53, 54). Irregular ridges of silica present on dorsal side, near junction of valve face and mantle (Figs 53, 56, 59). Striae uniseriate, composed of round areolae occluded by individual hymens, situated in shallow, continuous groove (Figs 53–54, 58–59), 34–40 in 10 µm. Fibulae irregularly shaped. Transapically running grooves interrupted apically near keel (Figs 53, 59). External central raphe endings clearly bent, interruption in raphe slit not visible (Figs 54, 58). Distal raphe endings clearly hooked (Figs 54, 56). Internally, fibulae not equidistant (Fig. 55). Each fibulae connected to 1–4 transapically costae (Fig. 55). Central raphe endings deflected to same direction, close together (Fig. 60). Transapical striae forming narrow, deep, parallel grooves (Figs 55, 60).

Type:— Indonesia, Molouki, Kairatu, 3°21’46.5”S 128°22’19.48”E, coll. date. 28 June 2018, holo - slide no. SZCZ28484! and the unmounted material with the same number at the Szczecin Diatom Collection (University of Szczecin, Poland), iso - slide no. 2018/445 and the unmounted material with the same number at the University of Rzeszow, Poland. The type population is illustrated on Figs 16–27 and 53–60 .

Etymology:— The species is named after Polish writer, laureate of the 2018 Nobel Prize in Literature Olga Tokarczuk to honour her work.

Distribution:— Observed in few moss samples from West Seram. It was found in moss samples collected from various substrates and habitats like soil on cropped fields, secondary shrublands and concrete wall in city in which they form the largest population (ca. 10% share in assemblage).

Associated diatom flora:— H. amphioxys (Ehrenberg) Grunow (in Cleve & Grunow 1880: 103), Hantzschia minima sp. nov., Humidophila contenta (Grunow) Lowe, Kociolek, Johansen, Van de Vijver, Lange-Bertalot & Kopalová (2014: 357), H. lacunosa (Moser, Lange-Bertalot & Metzeltin) Lowe, Kociolek, Johansen, Van de Vijver, Lange-Bertalot & Kopalová (2014: 358), H. subtropica (Metzeltin, Lange-Bertalot & Garcia-Rodriguez) Lowe, Kociolek, Johansen, Van de Vijver, Lange-Bertalot & Kopalová (2014: 354), Luticola intermedia (Hustedt) Levkov, Metzeltin & Pavlov (2013: 138), L. mitis Levkov, Metzeltin & Pavlov (2013: 161) and Pinnularia borealis Ehrenberg (1843: 420) .