Geissleria frolikhiensis Kulikovskiy, Gusev, Andreeva & Annenkova, 2014

Kulikovskiy, Maxim, Gusev, Evgeniy, Andreeva, Svetlana & Annenkova, Natalia, 2014, Phylogenetic position of the diatom genus Geissleria Lange-Bertalot & Metzeltin and description of two new species from Siberian mountain lakes, Phytotaxa 177 (5), pp. 249-260 : 252

Geissleria frolikhiensis Kulikovskiy, Gusev, Andreeva & Annenkova sp. nov. Figs 20–42

LM, live cells ( Figs 36–39 ): The single, large chloroplast is divided into two plates lying one against each valve, connected by a broad column.

LM ( Figs 20–35 ): Valves elliptical to linear-elliptical with ends obtusely rounded. Length 8.0–9.5 µm, breadth 5 µm. Raphe filiform.Axial area very narrow, linear. Central area small. Isolated pore lacking. Striae radiate throughout, 18–20 in 10 µm.

SEM, external view ( Fig. 40 ): The raphe slit is straight with visible sternum. Isolated pore absent. Central raphe ends straight. Terminal raphe ends deflected towards the secondary side of the valve and continue onto mantle. Striae uniseriate or irregularly biseriate near axial area. Annulus structure is not recognizable with striae similar to ones of striae. Areolae present as short slits, 70 in 10 µm of stria length.

SEM, internal view ( Figs 41, 42 ): Raphe slit lying in internal sternum. Central raphe endings straight, terminal ends terminate in evident helictoglossae. Elongated subpolar areolae (about 4, two of which are striae) with warty outgrowths. Internally no hymens or occlusions are observed on the areolae.

Type: — RUSSIA: Lake Frolikha , N 55027.005 E 109058.649, 26.07.2012, leg. M. Kulikovskiy ( IBIW slide no. 80/ B369, holotype designated here (= Fig. 20 )), COLO slide 80/B369p is isotype .

Etymology: —Epithet refers to the type locality.

Observations: This species is similar to Geissleria acceptata (Hustedt) Lange-Bertalot & Metzeltin (1996: 64) but differs by rather large valves and more elliptical valves (not linear-elliptical). G. acceptata possesses an isolated pore, a structure that is absent in G. frolikhiensis sp. nov. ( Novais et al. 2013). Other similar species are absent from Europe or elsewhere (see Lange-Bertalot 2001, Novais et al. 2013). G. irregularis Kulikovskiy, Lange-Bertalot & Metzeltin (2012: 117) from Lake Baikal differs by asymmetrical valves to the apical axis, central area. No similar species are known from Lake Baikal.

Figures

FIGURES 20–42. Geissleria frolikhiensis sp. nov. Figs 20–42: Figs 20–35: Valve view. Figs 36–39: Live cells with chloroplast structure, explanation in the text. Fig. 40: External valve view, note biseriate striae near axial area (arrow). Figs 41, 42: Internal valve view, note props in areolae and elongated subpolar pores (annulus). (20–39: LM; 40–42: SEM). Scale bar for LM: 10 μm.