Adlafia vietnamensis Glushch., Kulik. & Kociolek, 2020

Glushchenko, Anton M., Kociolek, John Patrick, Kuznetsova, Irina V. & Kulikovskiy, Maxim S., 2020, Four new species from the diatom (Bacillariophyceae) genus Adlafia Moser, Lange-Bertalot & Metzeltin from waterbodies of Vietnam, PhytoKeys 162, pp. 13-27 : 13

Adlafia vietnamensis Glushch., Kulik. & Kociolek sp. nov. Figs 5 , 6

Holotype.

Slide no. 00325 in collection of Maxim Kulikovskiy at the Herbarium of the Institute of Plant Physiology Russian Academy of Science, Moscow, Russia, represented here by Fig. 5G .

Type locality.

Vietnam. Khánh Hòa Province, Suối Tiên River, benthos and periphyton, 12°12.199'N, 109°01.694'E, 68 m elev., leg. E.S. Gusev, 02.07.2012.

Description.

LM (Fig. 5A-K ). Valves linear-elliptical with capitate to subcapitate ends. Length 15-22 μm (18.5 ± 1.6; n = 20), breadth 3.5-5.0 μm (4.3 ± 0.4; n = 20). Axial area narrow, almost linear. Central area weakly expressed. Raphe filiform. Striae radiate, becoming abruptly convergent approaching apices, 32-34 in 10 μm (33 ± 0.4; n = 20). Areolae not resolved in LM.

SEM, external view (Fig. 6A-C ). Valve face flat. Axial area linear. Central area weakly expressed. Raphe filiform. Proximal raphe endings slightly expanded, deflected. Distal raphe endings positioned on the valve mantle, hooked and curved in the same direction, and terminating at the junction valve face. Striae uniseriate. Areolae rounded or rectangular, occluded by hymenes. Slit-like opening of apical areolae invisible. Areolae 50-55 in 10 μm (52.5 ± 1.0; n = 20).

SEM, internal view (Fig. 6D-F ). Raphe straight, lying in a prominent and raised raphe-sternum. Proximal raphe endings deflected towards primary side of valve. Distal raphe endings terminating in small helictoglossae. Striae continuing onto valve mantle. Short striae alternate with longer striae at the center of the valve. Areolae rounded or rectangular. The openings of apical areolae apically elongated.

Etymology.

Epithet refers to the country where the new species was found.

Distribution.

Vietnam. Slides no. 00325 (type locality) and no. 04633.

Figures

Figure 5. A-K Adlafia vietnamensis Glushch., Kulik. & Kociolek, sp. nov. LM, DIC, size diminution series. Slides no 00325 (B-K) and 04633 (A). Holotype (G). Scale bar: 10 μm.

Figure 6. A-F Adlafia vietnamensis Glushch., Kulik. & Kociolek, sp. nov. SEM, sample no 00325 A-C external views. D, E internal views A whole valve B central area C valve end D whole valve E central area F valve end. Scale bars: 2.5 μm (A, D), 1 μm (B, C, E), 0.5 μm (F).