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

(Figs 4-6)

HOLOTYPE. — Slide no 02547; illustrated in Fig. 4B in collection of Maxim Kulikovskiy at the Herbarium of the Institute of Plant Physiology Russian Academy of Science, Moscow, Russia.

TYPE LOCALITY. — Tajikistan, Pamir Mountains, Mountain pass Maisara (Kok-Bay), unnamed river, periphyton (37°28.269’N, 72°38.958’E).

ETYMOLOGY. — The specific epithet “ pamirensis ” refers to the name of the Mountain range where this species was observed.

DISTRIBUTION. — As yet known only from the type locality.

DESCRIPTION

Valves

Asymmetrical about the apical axis, weakly arcuate to almost linear with capitate to rostrate apices, length 42-45 µm, breadth 5.5-7.0 µm.

Axial area

Narrow, slightly expanded to the central part of valve.

Central area

Unilaterally tumid on the concave margin, large, with ghost striae. Striae parallel, 16.5-18.0 in 10 µm.

SEM, external views (Fig. 5)

Striae uniseriate, comprised of small, rounded areolae (Fig. 5 B-D). Marginal spines flattened (Fig. 5). Areolae number 75-80 /10 µm within a stria.

SEM, internal views (Fig. 6)

Striae are located alternatively on each side (Fig. 6). On central area there are false striae (Fig. 6B). Areolae slit-shaped (Fig. 6 B-F). Ocellimbi are present on both valve ends (Figs 6 C-F). A single rimoportula on one end of valve (Fig. 6A) and comprised of two thickened strips of silica on either side of a slit-like opening (Fig. 6 C-E). Rimportulae are located near the ocellimbi, oriented either perpendicularlyto the striae, Fig. 6E) or laterally (oriented parallel to the striae; Fig. 6C, D).