Hannaea dorofeyukae Kulikovskiy, Glushchenko, Q.Liu & Kociolek, sp. nov.

(Figs 11-14)

HOLOTYPE. — Slide no 02694; illustrated in Fig. 11C in collection of Maxim Kulikovskiy at the Herbarium of the Institute of Plant Physiology Russian Academy of Science, Moscow, Russia, leg. M.S. Kulikovskiy and E.S. Gusev.

TYPE LOCALITY. — Mongolia. Khövsgöl Lake, periphyton, 27.VII.2015 (N50°47.215’, E100°31.837’).

ETYMOLOGY. — Species dedicated to Nadezhda Dorofeyuk, renown Russian algologist and specialist of the Mongolian diatom flora.

DISTRIBUTION. — Type locality and slides no 02687, 02694, 03097, 03098.

DESCRIPTION

Valves

Arcuate, smoothly tapering to the ends with capitate to rostrate apices, length 45-91 µm, breadth 6-7 µm.

Axial area

Narrow, linear, expanded at the central area.

Central area

Large, unilaterally expanded and swollen on the concave margin of the valve without ghost striae. Striae parallel, 14-16 in 10 µm.

SEM, external views (Fig. 13)

Valve face is flat (Fig. 13A). Spines are present on some valves (Fig. 13 B-D). Striae uniseriate or biseriate going from valve face to the mantle. Uniseriate striae present on the side opposite from unilaterally-expanded central area (Fig. 13B, C). Uniseriate striae also evident in central part of valve near the central area (Fig. 13C). Axial area is narrow and evidently broader to the central area. Central area is large, unilaterally-expanded on the ventral side of the valve; ghost striae are wanting (Fig. 13 A-D). Small round or slit-like openings of rimportue are present on each valve end. Ocellimbi are present on mantle on each valve apex (Fig. 13E, F).

SEM, internal views (Fig 14)

Striae uniseriate or biseriate lying in narrow depressions (Fig. 14 B-E). Uniseriate striae present especially in the central part of valve (Fig. 14 B-E). Striae extend onto the mantle (Fig. 14B). Axial area is narrow and evidently broader near the central area. Central area is large, unilaterally-expanded on the ventral side, without ghost striae (Fig. 14A, B, E). One rimoportula is present at each valve apex. Ocellimbi are present on each valve ends on the mantle.