The diatom genus Gomphoneis Cleve (Bacillariophyceae) from Lake Baikal, Russia Author Kociolek, John P. Museum of Natural History and Department of Ecology and Evolutionary Biology & University of Colorado, Boulder, Colorado, 80309 USA Author Kulikovskiy, Maxim S. I. D. Papanin Institute for Biology of Inland Waters Russian Academy of Sciences, Author Solak, Cüneyt N. Dumlupiner University, Department of Biology, Art & Science Faculty, Kütahya, 431000, Turkey text Phytotaxa 2013 2013-12-17 154 1 1 37 http://dx.doi.org/10.11646/phytotaxa.154.1.1 journal article 10.11646/phytotaxa.154.1.1 1179-3163 5100778 Gomphoneis tumida (Skvortzow in Skvortzow & Meyer) Kociolek & Stoermer (1988: 104)( Figs 89–119 , 382–387 ) Valves lanceolate clavate, with broadly rounded headpole and rounded footpole. Axial area narrow, expanded to form an orbicular central area containing 4–6 isolated stigmoids. Length 25–51 µm , breadth 6-9 µm . Raphe lateral, with proximal ends just reaching into the central area. Striae costate, radiate about the center, becoming parallel towards the apices. Striae 14-19/ 10 µm . Apical pore fields distinct. Septa and pseudosepta present at the apices. Externally in the SEM G. tumida has proximal raphe ends that are dilated, and 4 isolated stigmoids with rounded openings ( Fig. 382 ). Internally, the central area is rounded, and bears the internally raised central nodule ( Figs 383–387 ). The proximal raphe ends are received in the same direction. The stigmoidal openings are elliptical in outline and have teeth-like projections ( Figs 383–387 ). Helictoglossae are positioned at the poles. There are both septa ( Fig. 383 ) and pseudosepta ( Figs 385, 386 ) at the poles. Observations:— This represents a more narrow view of this taxon than the one presented by Kociolek & Stoermer (1988b) , but it is still considered one of, if not the most variable species present in Lake Baikal. This species is more linear than G. tumidioides .