Luticola subcrozetensis Van de Vijver, Kopalová, Zidarova & Levkov

Chattová, Barbora, Lebouvier, Marc, Haan, Myriam De & Vijver, Bart Van De, 2017, The genus Luticola (Bacillariophyta) on Ile Amsterdam and Ile Saint-Paul (Southern Indian Ocean) with the description of two new species, European Journal of Taxonomy 387, pp. 1-17 : 5-6

Luticola subcrozetensis Van de Vijver, Kopalová, Zidarova & Levkov

Figs 13‒26

Diatoms of Europe: Diatoms of the European Inland Waters and Comparable Habitats 7: 228, pl. 46 figs

15‒31, pl. 47 figs 4‒6 ( Levkov et al. 2013).

Type

ILE DE LA POSSESSION: Crozet Archipelago , sub-Antarctica, 5 Dec. 1999, B. Van de Vijver (holo-: slide no. BR ‒4290; iso-: slides BRMZU9 /25, MKNDC 006278 / B).

Description

Light microscopy ( Figs 13–22 )

Valves rhombic-lanceolate to elliptic-lanceolate and even elliptic in smaller specimens with clearly convex margins and broadly rounded, non-protracted apices. Valve dimensions (n = 25): length 12‒ 29 µm, width 7.0‒8.5 µm. Axial area linear, slightly widening towards apices and central area. Central area bow-tie shaped, wider opposite the isolated pore, bordered by shortened striae on both sides. An isolated pore present in the central area, located halfway between the valve centre and the valve margin. Raphe branches straight, bent away from the isolated pore at both proximal and distal ends. Striae radiate throughout the entire valve, 15‒17 in 10 µm.

Scanning electron microscopy ( Figs 23–26 )

Striae composed of 3–5 small, rounded to slightly elongated areolae at the apices, only 1–2 rounded areolae per stria, extending past the terminal raphe fissures on the valve face ( Fig. 23 ). A single row of rounded areolae present along entire valve mantle, interrupted at apices ( Fig. 26 ). Isolated pore rounded, slightly elongated, not associated with a stria. Central area usually bordered by one, rarely two, series of small, rounded areolae. Raphe branches straight to slightly curved. Proximal raphe endings bent to the side opposite the isolated pore, terminating into weakly developed pores. Terminal raphe fissures bent to the same side as the proximal endings terminating on the valve face, not extending onto the mantle ( Fig. 24 ).

Ecology and distribution

Luticola subcrozetensis is a typical sub-Antarctic and Maritime Antarctic species. Originally described from Ile de la Possession (Crozet archipelago), the species was also reported from Livingston Island ( Zidarova et al. 2016), one of the major South Shetland Islands, located in the southern Atlantic Ocean. The species was recently found in moss samples from Gough Island (Vinšová, unpubl. res.). It was present in samples from both Ile Saint-Paul and Ile Amsterdam.

The largest population was observed in a soil sample collected near the rockhopper penguin rookery of Ile Saint-Paul, at an altitude of 110 m, hidden in cracks in the rocks that border the penguin rookery.

Figures

Figs 13–26. Luticolasubcrozetensis VandeVijver et al. Light(LM) and scanning electron micrographs (SEM) of a population from Ile Saint-Paul. 13–22. LM of valve face views. 23–24. SEM of external view showing composition of striae and typical raphe structure. 25–26. SEM girdle view. Scale bars: 13‒22 =10 µm; 23‒26 = 5 µm.