Catenulopsis baweana Luthfi, Witkowski, M. Rybak & Kryk, 2024

Luthfi, Oktiyas Muzaky, Arsad, Sulastri, Kryk, Adrian, Risjani, Yenny, Yunianta,, Rybak, Mateusz, Peszek, Łukasz, Wróbel, Rafał J., Pappas, Janice L., Bąk, Małgorzata & Witkowski, Andrzej, 2024, New genera and new species of Catenulaceae (Bacillariophyta) from Coral Reef habitat of two Indonesia islands — Bawean and Sulawesi — A morphological approach, PhytoKeys 248, pp. 263-291 : 263-291

Catenulopsis baweana Luthfi, Witkowski, M. Rybak & Kryk sp. nov.

Holotype.

Slide number SZCZ 27552 at the repository of the University of Szczecin.

Type locality.

Sand and rubbles of coral reef at Gili Iyang harbour , Bawean Island, East Java, Indonesia.

Etymology.

The name of the species is derived from the geographic location of the type habitat, i. e., Bawean Island. The meaning of Bawean in Sanskrit is sunlight.

Distribution.

The diatom species Ca. baweana has a unique distribution, being found exclusively on Bawean Island, Indonesia.

Description.

Light microscopy (Fig. 10 A – S ): Valves are asymmetrical, dorsiventral, with the dorsal margin curved and the ventral margin straight. Valves are 10.7–16.1 μm long (n = 19) and 1.8–3.1 μm in width (n = 19). The apices look subcapitate when focusing on multiple planes using LM; the helictoglossae appear as a darker grey spot. A white line appearing near the ventral margin is a raphe. The frustule in girdle view is rectangular or widely rectangular because it consists of several cingula. Transapical striae are difficult to resolve with LM.

Scanning electron microscopy (Fig. 10 T – AB): Frustules strongly dorsiventral, rectangular in girdle view around 1.9–2.9 µm deep (Fig. 10 T – V, X ). The girdle is composed of several perforated bands (2–3 cingula), each with uniseriate small pores, 50–65 in 10 μm. Valves strongly asymmetrical about the apical axis, 8.8–17.1 μm long (n = 17) and 1.7–2.9 μm in width (n = 9). External and internal valves are flat and end abruptly at the mantle. The dorsal margin is gently arched, and the ventral margin is straight, apices obliquely cuneate. Raphe sternum is positioned close to the ventral margin, raphe slits almost straight. External proximal and apical ends are simple, bent towards the valve ventral margin. Proximal raphe ends somewhat distant from each other, 1.3–1.9 μm. Transapical striae present only on the valve face, dorsal and ventral mantle, and composed of long linear slits, 22–34 in 10 μm (n = 12). The internal valve face is flat. The areolae are closed with hymenate occlusions. Internally, raphe slits are very straight and skewed towards the dorsal area, and the proximal raphe ends terminate in a slightly expanded drop-like structure, whereas apically, they terminate in small helictoglossae.

Figures

Figure 10. Catenulopsis baweana Luthfi, Witkowski, M. Rybak & Kryk, sp. nov. A – S light micrographs T – AB SEM images T girdle view of the whole frustule U perforated valvocopula of frustule V, W detail of striation in the ventral mantle X frustule of diatoms attached at valve face Y, AA external view of valves semi-lanceolate dorsiventral with raphe branches. Proximal and apical endings deflected to ventral side Z – AB internal valve view shows simple raphe slits. Scale bar: 10 µm (A – S).