Luticola malukuana M.Rybak & J.P. Kociolek, 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 malukuana M.Rybak & J.P. Kociolek sp. nov.

Figs 2A-S , 7A-H

Description.

LM observations (Fig. 2A-S ). Frustules rectangular in girdle view, larger valves linear-lanceolate with weakly-protracted apices and slightly undulating margin, smaller valves elliptic-lanceolate. Range of valve dimensions (n = 35): 12.0-28.0 μm long, 5.5-7.0 μm wide and 18-21 striae in 10 µm. Striae clearly punctate. Central area rectangular to slightly bow-tie-shaped, axial area linear and narrow. Isolated pore clearly visible in central area. Raphe filiform with proximal endings slightly bent away from isolated pore, distal raphe endings barely visible.

SEM observations (Fig. 7A-H ). External view: Striae composed of 3-4 round to slightly elongated areolae (Fig. 7A-D ). Single row of elongated areolae, interrupted at valve apices, present on valve mantle (Fig. 7B, D ). Central area bordered by 3-4 areolae (Fig. 7A-D ). Raphe filiform with weakly-hooked distal endings continuing on to valve mantle (Fig. 7A-D ). Proximal raphe endings deflected away from isolated pore (Fig. 7A-D ). External opening of isolated pore round and not associated with striae (Fig. 7A-D ). Girdle bands numerous and open with two rows of poroids (Fig. 7E, F ).

Internal view: Areolae occluded by hymenes forming continuous strips (Fig. 7G, H ). Raphe slits straight (Fig. 7G, H ). Proximal raphe endings simple and straight (Fig. 7G, H ). Isolated pore opening with small circular structure (Fig. 7G, H ). Longitudinal channels visible along valve (Fig. 7G ).

Type.

Indonesia, Seram, Amahai City, 3°19'12.2"S, 128°56'6.94"E, 14 m a.s.l., coll. 29 June 2018, holotype slide no. SZCZ29104! Additionally , the unmounted material with the same number in the Szczecin Diatom Collection (University of Szczecin, Poland), isotype slide no. 2018/447 and the unmounted material with the same number at the University of Rzeszów , Poland. The type population is illustrated on Figs 2A-S , 7A-H .

Etymology.

Name refers to Maluku Islands where the species was found.

Distribution.

So far, this species has been observed only in the type locality.

Ecology and associated diatom flora.

The species was observed in a sample characteried by a circum-neutral pH (6.7) and conductivity of 680 µS /cm. The species was the most abundant taxon in an assemblage including: Humidophila lacunosa (Moser, Lange-Bertalot & Metzeltin) Lowe, Kociolek, Johansen, Van de Vijver, Lange-Bertalot and Kopalová, Luticola hustedtii Levkov, Metzeltin & Pavlov, Luticola intermedia Levkov, Metzeltin & Pavlov and Luticola sublagerheimii Levkov, Metzeltin & Pavlov.

Figures

Figure 2. LM microphotographs of Luticola malukuana sp. nov. in size diminution series. W, S - frustule in girdle view. Scale bar: 10 µm.

Figure 7. SEM microphotographs of Luticola malukuana sp. nov. external (A-F) and internal (G, H) views. Arrow indicate a longitudinal channel. Scale bars: 5 µm (A-G); 3 µm (H).