Paracatenula Witkowski, Luthfi & 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 Witkowski, Luthfi & M. Rybak gen. nov.

Etymology.

The name of the genus is derived from its resemblance to Catenula . “ Para ” in Greek means alongside, besides, near, resembling, beyond, apart from, and abnormal, referring to the superficial similarity of the new genus to Catenula but does not conform to the type of the genus as typified with C. pelagica Mereschkowsky. Paracatenula means resembling Catenula .

Description.

Frustules strongly dorsiventral attached with valve faces to form short chains, plastid unknown. In girdle view, several bands perforated with one or two rows of small pores. Valves asymmetrical about the apical axis with dorsal margin gently arched and ventral margin straight usually with apices slightly deflected towards the ventral side. Raphe sternum positioned close to the ventral margin, raphe slits externally almost straight with simple proximal and apical ends. Striae on valve face usually absent or observed as shallow transapical grooves filled in with silica. On the dorsal mantle, solitary pore-like areolae present, whereas on the dorsal mantle, short striae usually composed of several small poroids. Valve face internally hyaline without any areolae, and valve mantle having a row of areolae along the valve margin, which is occluded by hymens. Internally, raphe slits are bent toward the dorsal margin and proximally terminate in a simple somewhat raised end, whereas apically, they terminate in oblique helictoglossae. Present sulcus in apical area. The sulcus clearly found in the internal view of the diatom valve after the distal ending (Fig. 3 B ).

Figures

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.