Gomphoneis metzeltinii Kociolek, Kulikovskiy & Solak, 2013

Kociolek, John P., Kulikovskiy, Maxim S. & Solak, Cüneyt N., 2013, The diatom genus Gomphoneis Cleve (Bacillariophyceae) from Lake Baikal, Russia, Phytotaxa 154 (1), pp. 1-37 : 14

Gomphoneis metzeltinii Kociolek, Kulikovskiy & Solak , sp. nov. ( Figs 169–174 ; 389–391 )

Valves lanceolate-clavate with headpole protracted, rounded and footpole rounded. Length 14.5–32.0 µm, breadth 4.0– 5.5 µm. Axial area narrow, straight, expanded laterally to form a rectangular to bow-tie shaped central area, with 1–2 shortened striae on either side at the margins, more coarsely arranged than other striae. 4 isolated stigmoids arranged around the central area, usually offset from one another. Raphe lateral, weakly undulate, with external proximal raphe ends rounded and distal raphe ends straight and extending onto the valve mantle. Costate striae radiate, except parallel at the headpole. Striae 10–14/ 10 µm. Apical pore fields small, indistinct. Septa and pseudosepta present at the poles.

This species have doubly-punctate striae, isolated stigmoidal openings that are indistinct and appear similar to the areolae, and proximal raphe ends that are dilated ( Figs 389, 390 ). Areolae are small, round and unoccluded ( Figs 389, 391 ). The apical pore field is present on the valve face and mantle ( Figs 389, 391 ).

Type:— RUSSIA: Lake Baikal , Boldakovo, on algae, N52 o 35.694, E107 o 17.142, 16.07.2011, leg. M. Kulikovskiy ( IBIW slide no. 18572m, holotype designated here (= Fig. 169 ); COLO slide no. 18572p, SZCZ slide no. 18572a, isotypes) .

Etymology:— Named in honor of our friend and colleague, Ditmar Metzeltin, Frankfurt ( Germany) for his many contributions of our understanding of freshwater diatom biodiversity on a worldwide scale.

Figures

PLATE 7: LM. Figs 169–174: Gomphoneis metzeltinii sp. nov. Fig. 169 is of the holotype. Figs 175–192: G. cf. subcapitata. Figs 193– 200: G. subcapitata sp. nov. Fig. 200 is of the holotype. Figs 201–214: G. inconspicua sp. nov. Fig. 201 is of the holotype. Figs 215– 222: G sp. cf. subcapitata. Figs 223–228: G. reichardtii sp. nov. Fig. 223 is of the holotype. Figs 229–237: G. sp. cf. skabitchevskii. Figs 238–250: G.sp. cf. skabitchevskii. Figs 251–260: G. skabitchevskii sp. nov. Fig. 258 is of the holotype. Figs 261–282: G.sp. cf. reichardtii. Scale bar = 10 µm for all figures.

PLATE 14: SEM. Gomphoneis metzeltinii. Figs 389–391: Extenal valve views. Figs 389, 390: Whole valve views should fine striae and indistinct stigmoids. Proximal raphe ends are dilated slightly. Fig. 391. Footpole shows the rounded porelli of the apical pore field appear as condensed striae. G. capitata. Figs 392–396: Figs 392–395: Internal valve views. Figs 392–394: Entire valve views. Fig. 392: Specimen with girdle bands shows septa at the poles, wide, rectangular central area and central nodule with recurved proximal raphe ends. Fig. 393: Specimen lacking girdle bands revealing the smaller pseudosepta at the poles. The helictoglossae are evident also. Only two stigmoid openings are evident around the central nodule. Fig. 394: Specimen without girdle bands, showing pseudosepta, recurved proximal raphe ends on small central nodule, and helictoglossae at the poles. Fig. 395: Internal valve view showing only two prominent stigmoidal opening. The appear simple, without occlusions. Fig. 396: External valve view. The valve has proximal raphe ends that are prominently dilated, and has 2 types of stigmoidal openings, one larger and one smaller.