Gliwiczia latarea Kulikovskiy, Lange-Bertalot & Witkowski, 2013

Kulikovskiy, Maxim, Lange-Bertalot, Horst & Witkowski, Andrzej, 2013, Gliwiczia gen. nov. a new monoraphid diatom genus from Lake Baikal with a description of four species new for science, Phytotaxa 109 (1), pp. 1-16 : 8-10

Gliwiczia latarea Kulikovskiy, Lange-Bertalot & Witkowski sp. nov. Figs 67–88

Frustules with a horse shoe-like internal cavum at both raphid and rapheless valve as characteristic of the genus. Valves broadly elliptical with broadly rounded ends. Length 11–15 µm, breadth 6.5–9.5 µm.

LM, raphe valve ( Figs 79–83 ): Raphe filiform, straight, central ends slightly expanded, distal ends hardly noticeably deflected to opposite sides. Axial area narrow, linear, barely widened proximally. Central area forming a narrow, ca. 1 µm broad stauros at both sides but unilaterally masked towards margins by the elliptical cavum. Striae radiate throughout but becoming progressively stronger radiate to the ends 27-33 in 10 µm. Areolae difficult to discern, more than 30 in 10 µm.

LM, rapheless valve ( Figs 67–78 ): Axial and central area merging to a wide elliptical space, striae therefore restricted to a marginal zone. Nevertheless on the side opposite to the cavum a short stauros is clearly marked. Striae 21–24 in 10 µm.

SEM, raphe valve, internal view ( Fig. 84 ): Central raphe ends deflected clearly to opposite sides. The stauros together with the raphe sternum is elevated above the internal valve surface. Cavum in circle shape present extended on the one side of the sternum. Areolae uniseriate, small, approximately circular or elongated.

SEM, rapheless valve, internal view ( Figs 85–88 ): The internal nonperforated area is not simply flat but a narrow sternum and similarly to the stauros relief-like elevated. Vestiges of a raphe are present. The cavum appears prominently extended ca. 1/4 of the valve width. Areolae, ca. 40 in 10 µ m, are occluded by membranes.

Type: slide no. 15645m (holotypus here designated see Fig. 68 ) in collection Maxim Kulikovskiy, I.D. Papanin Institute for Biology of Inland Waters , Russian Academy of Sciences ( IBIW) 20.07.1965, leg. A.P. Skabitschewsky.

Isotype: slide no. 15645a in collection Andrzej Witkowski, Institute of Marine Sciences, University of Szczecin (SZCZ).

Distribution: only found in Lake Baikal associated with the other three taxa described here as new.

Etymology: latarea in Latin means possessing a broad area

Figures

FIGURES 67–88: Gliwiczia latarea sp. nov. Figs 67–88: Figs 67–78: Valve view of rapheless valves. Fig. 67: arrow indicates presence of cavum in sternum valve. Figs 79–83: Valve view of raphe valves. Fig. 79: arrow indicates presence of cavum in raphe valve. Fig. 84. Internal view if raphe valve note presence of cavum. Figs 85, 87, 88: Internal valve view of rapheless valves, note presence of striae in central part opposite cavum. Fig. 86. Internal view of valve part with cavum (67–78: LM; 84–88: SEM). Scale bar: 10 µm.