Luticola seposita (Hustedt) D.G.Mann

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 seposita (Hustedt) D.G.Mann

Figures 10 , 11

Description LM.

Valves linear-elliptic to elliptic with weakly undulate margins, with rounded, rostrate to capitate apices, 16.8-24.4 μm in length, 9.5-12.4 μm in width (n = 20). Axial area narrowly-lanceolate. Central area bordered by two or three shortened striae with slit-like stigma positioned close to the valve margin. Transapical striae radiate becoming strongly radiate toward apices, 14-17 in 10 μm.

Description SEM.

Valve face flat, raphe filiform and straight, distally strongly hooked at the apices. External proximal raphe endings bent to side opposite the stigma with small C-shaped grooves. Internally, raphe straight, only proximal endings slightly bent, with distal raphe endings terminating in small helictoglossae. Transapical striae composed of 4-5 round to slightly elongated areolae. Single row of areolae present also on valve mantle. Internally, areolae occluded with hymen forming continuous strips. External elongate ghost areolae present within central area. External opening of stigma slightly elongate and positioned close to valve margin. Internally, as a large-lipped structure positioned mid-way between valve margin and valve center. Internally, longitudinal channel is present along the valve margin, with small siliceous flap on side opposite to stigma.

Distribution.

This species was observed only in epilithic sample from a sampling site called Fenjiezhou Island located on the coast of Hainan Island, NW South China Sea (China) in sample SZCZ27176.

Figures

Figure 10. LM micrographs of Luticola seposita (Hustedt) D. G. Mann in size diminution series (A-R). Scale bar: 10 µm.

Figure 11. SEM micrographs of Luticola seposita (Hustedt) D. G. Mann. External view of valve (A, B). Detailed external views showing proximal raphe endings with C-shaped grooves C stigma opening D and distal raphe ending E internal view of valve F detailed internal views showing proximal raphe endings, stigma opening and hymenate structure G and distal raphe ending H. Scale bars: 10 µm (A, B, F), 3 µm (C, E), 4 µm (D), 2 µm (G, H).