Gomphonema paracapitatum Kulikovskiy, Kociolek & Solak, 2015

Kulikovskiy, Maxim S., Kociolek, John P., Solak, Cüneyt N. & Kuznetsova, Irina, 2015, The diatom genus Gomphonema Ehrenberg in Lake Baikal. II. Revision of taxa from Gomphonema acuminatum and Gomphonema truncatum-capitatum complexes, Phytotaxa 233 (3), pp. 251-272 : 260

Gomphonema paracapitatum Kulikovskiy, Kociolek & Solak , sp. nov. ( Figs 214–227 , 294 )

Valves clavate, swollen at the center of the valve. Central undulation slightly larger than headpole. Length: 26.7–44.0 μm, breadth: 8.7–10.0 μm. Headpole is broadly rounded, capitate and the footpole is more narrow. Footpole broadened at the end to form a flipper - like structure. Axial area is narrower. Central area small, rectangular. Raphe is lateral, undulate. A round stigma is present in the central area close to the proximal raphe endings. Striae punctuate, distinctly radiate, 11–12 in 10 μm. Apical pore fields evident at footpole. SEM: valves have areolae with volate occlusions, with C - shaped openings ( Fig. 294 ).

Type: — RUSSIA. Lake Baikal: Bay, Cladophora spp. on bottom, 52º 27.042’ N, 106º 53.215’ E, M. Kulikovskiy, 14 July 2011 (holotype: IBIW! slide no 18589 = Fig. 214 ).

Etymology: —Greek ‘para’ means besides of G. capitatum .

Observations: —This species is distinguished from G. capatatum and other closely - related taxa by the unusual flipper - like structure of the footpole.

Figures

FIGURES 187–227. LM. 191–213. Gomphonema cf. truncatum. 214–227. Gomphonema paracapitatum sp. nov. Fig. 214 is of the holotype. Scale bar = 10 μm.

FIGURES 292–297. SEM. 292. Gomphonema cf. truncatum. External views. Footpole, with deflected distal raphe end and apical pore field mostly on the valve mantle. Porelli are physically separated from and morphologically differentiated from C-shape areolae. 293. Valve view with undulate raphe and C-shaped areolae distinct. 294. Gomphonema paracapitatum sp. nov., external view. Girdle view showing wedge-shaped frustule and extension of striae from valve view onto mantle. 295–297. Gomphonema capitatum, external views. 295. General valve view. 296. Central area with distinct C-shaped areolae. Proximal raphe ends are dilated weakly. 297. Headpole, Cshaped areolae evident. Scale bars = 1 μm in Fig. 292; 5 μm in Figs 293, 294; 10 μm in Fig. 295; 2 μm in Figs 296, 297.