Luticola belawanensis Levkov & Metzeltin, 2013

Rybak, Mateusz, Witkowski, Andrzej, Peszek, Lukasz, Kociolek, John P., Risjani, Yenny, Nguyen, Duc Hung, Zhang, Jinpeng, Yunianta,, Nguyen, Van Duy, Gastineau, Romain, Duong, Thi Thuy, Rosa, Philippe & Meleder, Vona, 2021, Marine and brackish Luticola D. G. Mann (Bacillariophyta) species from the Java Sea and South China Sea coasts with the description of three new species, PhytoKeys 183, pp. 115-142 : 115

Luticola belawanensis Levkov & Metzeltin

Figure 6

Description LM.

Valves elliptic to elliptic-lanceolate with rounded apices. Valve length 8.4-19 μm, breadth 6.1-9.0 μm, with easily distinguishable radiate striae (18-21 in 10 μm) (n = 15). Axial area lanceolate. Central area asymmetrical, with wider side opposite the stigma, bordered on each margin by a row of areolae. Stigma elongated, located close to valve margin.

Description SEM.

Valve face flat, raphe filiform and straight, distally strongly hooked on valve face at the apices. Proximal raphe endings clearly bent to the side opposite the stigma with small C-shaped or irregular grooves evident. Internally, raphe straight, proximal endings only slightly bent, whereas distal raphe endings terminate in small helictoglossae. Transapical striae composed of 4-5 round to slightly elongate areolae. Single row of areolae occurs also on valve mantle. Internally, areolae occluded with hymen forming continuous strips. External opening of stigma slit-like, positioned close to valve margin but separated by a single areola. Internal stigma opening with large-lipped structure positioned mid-way between valve margin and valve center. Internally, longitudinal channel present along the valve margin, with small silica flap on side opposite the stigma.

Distribution.

Occurred rarely only in sample SZCZ26472 from Western South China Sea, Quáng Yên, in Ha Long region of NE Vietnam, collected from oyster shells in offshore aquaculture area.

Figures

Figure 6. LM pictures of Luticola belawanensis Levkov & Metzeltin in size diminution series (A-M). External view of frustule (N, O). Internal view of frustule (P, Q). Internal details of: raphe branch with distal raphe end and hymen structure R proximal raphe endings and longitudinal channel S proximal raphe endings and stigma opening T. Scale bars: 10 µm (A-M, P), 5 µm (N, O, Q, S), 3 µm (R, T).