Paracatenula porostriata Luthfi, Witkowski & M. Rybak, 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

Paracatenula porostriata Luthfi, Witkowski & M. Rybak sp. nov.

Type materials.

Holotype: Slide number SZCZ 27552 at repository of University of Szczecin.

Isotype: SZCZ 27553 at repository of University of Szczecin .

Type locality.

Rubble of coral reef at Gili Iyang harbour , Bawean Island, East Java, Indonesia

Etymology.

The species epithet ‘ porostriata ’ is a combination of the Latin words porus meaning pore or punctum and striatus meaning striated or having striations to show that this species consists of porous striations on the mantle and cingulum.

Distribution.

The diatom species P. porostriata sp. nov. has been consistently found in coral rubble specimens from both Gili Iyang harbor and MHD, Bawean Island.

Description.

Light microscopy (Fig. 2 A – N ): The valves are semi-lanceolate, apices broadly rounded, protracted and rostrate, which tend to deflect to the ventral side. The ventral margin is straight, and the dorsal side is smoothly arched or curved. Raphe slits are observed on the valve face as short lines. Valve length 10.1–25.4 µm (n = 25) and width 1.7–4.7 µm (n = 25). Striation is parallel in the middle and then slightly radial near the ends.

Scanning electron microscopy: (Fig. 2 O – U external view; Fig. 3 A – E internal view): valve shape semi-circular to semi-lanceolate dorsiventral. The surface of the valve, both externally and internally, is completely flat. The transition between the valve face and valve mantle is sharp with a slightly diminished rib. Central area is distinct only on the valve face; lack of fascia on valve mantle. Axial area wide on the dorsal side and narrower on the ventral side (Fig. 2 O, P ). Externally, the raphe is lateral, short, simple and positioned in close proximity to the edge of the ventral valve face. Proximal raphe ends straight, distance to each other is 3.8 µm (n = 12). Distal raphe ends straight, distance to the apices is 2.6 µm (n = 11). Externally, transapical striae are arranged by one row along the dorsal face about 14–20 in 10 µm. Uniseriate striae observed along the valve face (Fig. 2 O – R ). Sometimes, scattered unoccluded pores are found on apices (Fig. 2 O ). Girdle band open with two rows of pores (Fig. 2 S – T ). Frustules contain five girdle bands and have a rectangular form in girdle view (Fig. 2 U ). Internally, the raphe slits are short, simple, and arcuate, with proximal and distal ends bent toward the dorsal side. Raphe fissure terminating in distinct helictoglossae (Fig. 3 A – E ). Line-like and depressed siliceous areolae (Latin sulcus, plural sulci) are present internally at the apical areas, approximately 1.3 µm in length (Fig. 3 B ).

Figures

Figure 2. Paracatenula porostriata Luthfi, Witkowski & M. Rybak, sp. nov. A – N light micrographs O – U SEM images of external valve view O, P external view of valves, unoccluded pores at one or both apices are present (white arrowhead, O) Q protracted apex of valve R pores on the valve mantle shown in the white arrowhead S, T cingulum perforated by biseriate striae externally at the dorsal side (black arrowheads) and one row of elongated pores internally at the ventral side (white arrowhead, S) U whole girdle view of frustule, with depressed areolae on valve mantle. Scale bar: 10 µm (A – N).

Figure 3. Paracatenula porostriata Luthfi, Witkowski & M. Rybak, sp. nov. SEM images of internal view A valve with protracted apices B valve with linear grooves (Latin sulcus, plural sulci) on apices area (black arrowhead, also on A – E) C valve view showing occluded areola on ventral and dorsal valve mantel D, E internal apical raphe end bent and ending with indistinct helictoglossa.