Gliwiczia 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 : 3

Gliwiczia Kulikovskiy, Lange-Bertalot & Witkowski gen. nov.

Typus generis: Gliwiczia tenuis Kulikovskiy, Lange-Bertalot & Witkowski sp. nov.

Living cells have not yet been observed. Frustules are monoraphid, composed of a raphe-bearing valve (RV) and a sternum valve (SV), both valves possess consistently an internal cavum (horse shoe), and not only on SV as it is the case in Planothidium lanceolatum species group. The cavities are open towards the valve margin. The frustules are heterovalvate, however, with respect to the fine structure. The raphe valve of each species has a higher density of striae and areolae as the sternum one. The distal external raphe ends are slightly curved in opposite directions; central ends are weakly expanded. Internally central raphe ends are not co-axial as in other achnanthoid genera; distal ends have very weakly developed helictoglossae. Raphe valves are consistently slightly concave, whereas the sternum valves appear flat from external and internal view. An internal stauros consistently developed on the raphe valve of each species. A more or less strong staurose occurs likewise on the rapheless valve but is weakly developed in one of five known taxa. Species-specific is the length of transapical striae of the rapheless valve. Striae of all taxa are uniseriate and are extend onto the shallow valve mantle. Girdle elements have not been observed thus far. Areolae have open circular foramina externally. Internal apertures are occluded by membranes ( Figs 61, 62 , 64 , 86 , 106 ); below the occlusion a pair of foramina lips ( Figs 41, 42 ) probably facultatively occurs.

Etymology: generic name is dedicated to Professor Maciej Gliwicz from Warsaw University, in recognition of his outstanding research results in ecology and in behavioral ecology in aqueous environment in particular.

Figures

FIGURES 43–62: Gliwiczia tenuis sp. nov. Figs 43–66: Figs 43–55: Valve view of rapheless valves. Fig. 43: arrow indicates presence of cavum in sternum valve. Figs 56–58: Valve view of raphe valves. Fig. 58: arrow indicates presence of cavum in raphe valve. Figs 59: Internal valve view of rapheless valve. Fig. 60 Internal view of valve part with cavum. Figs 61, 62. Internal view of areolae covered by circular foramina, come off from areolae in fig. 61 (43–58: LM; 59–62: SEM). Scale bar: 10 µm.

FIGURES 63–66: Gliwiczia tenuis sp. nov. Figs 63–66: Fig. 63–64: Internal view of rapheless valves note shorter striae in central part of valve opposite cavum. Fig. 65. Internal view of raphe valve note presence of cavum. Fig. 66: External view of raphe valve. It is questionable whether this valve belongs to G. tenuis sp. nov. (SEM).

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.

FIGURES 89–107: Gliwiczia vixcalcar sp. nov. Figs 89-107: Figs 89–101: Valve view of rapheless valves. Fig. 89: arrow indicates presence of cavum in sternum valve. Figs 102, 103: Valve view of raphe valves. Fig. 103: arrow indicates presence of cavum in raphe valve. Figs 104–106: Internal valve view of rapheless valves. Fig. 106. Internal view of valve part, note the pore occlusion. Fig. 107: Internal view of raphe valve note presence of cavum (89–103: LM; 104–107: SEM). Scale bar: 10 µm.

FIGURES 37–42: Gliwiczia skvortzowii sp. nov. Figs 37–42: Figs 37–40: Internal valve view of rapheless valves. Figs 41–42: Internal view of rapheless valves, note pair of foramina lips. (SEM).