Luticola poliporea M.Rybak, Peszek, Luthfi, Arsad & A.Witkowski, 2024

Rybak, Mateusz, Peszek, Lukasz, Luthfi, Oktiyas Muzaky, Arsad, Sulastri, Kociolek, John Patrick & Witkowski, Andrzej, 2024, Description of five new Luticola D. G. Mann (Bacillariophyta, Diadesmidaceae) species from Indonesia with comments on the morphological boundaries of the genus, PhytoKeys 237, pp. 1-22 : 1

Luticola poliporea M.Rybak, Peszek, Luthfi, Arsad & A.Witkowski sp. nov.

Figs 3A-W , 8A-G , 9A-G

Description.

LM observations (Fig. 3A-W ). Frustules rectangular in girdle view, lanceolate or linear-lanceolate with rostrate apices. Range of valve dimensions (n = 100): 12.5-39.0 μm long, 5.3-9.0 μm wide and 20-24 striae in 10 µm. Striae clearly punctate. Central area slightly bow-tie-shaped, axial area linear and narrow. Isolated pores clearly visible in central area. Usually two isolated pores are present, in about 2% of the type population, a third isolated pore occurs (Fig. 3C, J, K, T, A, C ).

SEM observations (Figs 8A-G , 9A-G ). External view: Striae composed of 4-5 slightly elongated areolae, almost equal in size (Fig. 8A-G ). Single row of elongated areolae, interrupted at valve apices, present on the valve mantle (Fig. 8G , 9G ). Central area bordered by three areolae (Fig. 8A-F ), ghost areolae commonly present in central area (Fig. 8A-F ). Raphe filiform located on distinct raphe sternum (Fig. 8A-G ). Distal raphe endings hooked and continued on to valve mantle (Fig. 8G ), proximal raphe endings weakly deflected and finishing slightly pore-like enlarged (Fig. 8A-E ). External openings of isolated pores elongated located in mid-way between valve margin and valve centre. Isolated pore opening on side where raphe endings are deflected commonly are smaller and shifted from centre part into striae (Fig. 8A-E ). Edge of the valve mantle notched approximately half-way between centre and pole in each quadrant of the valve (Fig. 9C ).

Internal view: Areolae occluded by hymenes forming continuous strip (Fig. 9A-D ). Raphe slits straight (Fig. 9A-E ). Proximal raphe endings simple and straight (Fig. 9A-C, E, F ), distal raphe endings forming small helictoglossa (Fig. 9C, D ). Isolated pore openings with large circular structure (Fig. 9A-C, E, F ), openings of additional pores commonly reduced (Fig. 9B, C, F ). Longitudinal channels visible along valve (Fig. 9A-F ).

Type.

Indonesia, Malang, East Java, unnamed spring, 7°50'26.2"S, 112°31'43.0"E, coll. 2 July 2023. Holotype slide no. SZCZ28794! and unmounted material with the same number in the Szczecin Diatom Collection ( University of Szczecin , Poland), isotype slide no. 2023/81 and the unmounted material with the same number at the University of Rzeszow , Poland. The type population is illustrated in Figs 3A-W , 8A-G , 9A-G .

Etymology.

Name refers to the unusual feature of bearing multiple isolated pores.

Distribution.

So far, species observed only in the type locality.

Ecology and associated diatom flora.

The species was most abundant in a sample of moss from collected from spring - where it reached 30% of the total share in diatom assemblage; together with the described species, also occurred: Diadesmis confervacea Kützing, Mayamaea sp., various Nitzschia spp., Navicula cf. germainii Wallace and Sellaphora nigrii (De Notaris) Wetzel & Ector. The species was also observed in samples of other habitats from the same spring (sediments, epilithon), but in lower numbers.

Figures

Figure 3. LM microphotographs of Luticola poliporea sp. nov. in size diminution series. * - indicates valves with triple isolated pores. A initial valve, V, W frustule in girdle view. Scale bar: 10 µm.

Figure 8. SEM microphotographs of Luticola poliporea sp. nov. in external views. * - indicates valves with triple isolated pores. Scale bars: 10 µm (A-E); 5 µm (F, G).

Figure 9. SEM microphotographs of Luticola poliporea sp. nov. in internal views (A-F) and external details of valve mantle and girdle band (G). * - indicates valves with triple isolated pores, arrow indicates a longitudinal channel. Scale bars: 10 µm (A, C); 5 µm (B, E-G); 2 µm (D).