Luticola inserata (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 inserata (Hustedt) D.G.Mann

Figures 8 , 9

Description LM.

Valves lanceolate-elliptical to broadly elliptic with weakly undulated margins with rounded, rostrate to capitate apices, 12.2-33.5 μm in length, 8.2-14.0 μm in width (n = 20). Axial area narrow, gradually broadening towards valve center, central area rectangular, asymmetrical, bordered by two or three shortened striae with slit-like stigma located close to valve margin. Transapical striae radiate, becoming strongly radiate toward apices, 15-20 in 10 μm. Copulae open.

Description SEM.

Valve face flat, raphe branches filiform and straight. External proximal raphe endings clearly bent to the site opposite the stigma with irregularly-shaped grooves expanded opposite the stigma. External distal raphe endings terminate on apices, strongly hooked. Internally, raphe branches straight, only proximal endings slightly bent, distal raphe endings terminating in small helictoglossae. Transapical striae composed of 4-5 round to elongate areolae. Single row of elongate areolae occurs also on valve mantle. Both areolae on mantle and valve face with small spines on edges. Internally, areolae covered with hymen forming continuous strips. Ghost areolae rarely present within central area. External opening of stigma small and rounded, positioned very close to valve margin. 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.

This species was observed only in sample SZCZ26472 from Western South China Sea, Quáng Yên, in Halong region of NE Vietnam, shell scrape from oysters in offshore aquaculture area.

Figures

Figure 8. LM micrographs of Luticola inserata (Hustedt) D. G. Mann in size diminution series (A-R). Scale bar: 10 µm.

Figure 9. SEM micrographs of Luticola inserata (Hustedt) D. G. Mann. External view of valve (A, B). Detailed external views showing proximal raphe endings with irregular shallow grooves C distal raphe ending, areolae D stigma opening E internal view of valve F detailed internal view showing proximal raphe endings and stigma opening G and distal raphe ending and hymenate structure H open copulae I. Scale bars: 10 µm (A, F, I), 5 µm (B-D, G), 3 µm (E), 4 µm (H).