Luticola beyensii Van de Vijver, Ledeganck & Lebouvier

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 : 3-5

Luticola beyensii Van de Vijver, Ledeganck & Lebouvier

Figs 1‒12

Diatom Research 17: 235‒241 (Van de Vijver et al. 2002b).

Type

ILE SAINT PAUL: TAAF, sub-Antarctica , 16 Dec. 1999, B. Van de Vijver sample A9 (holo-: CAS 220051 , California Academy of Science; iso-: slide no. BR ‒4045, University of Antwerp, Belgium) .

Description

Light microscopy ( Figs 1–10 )

Valves rhombic-lanceolate with clearly convex margins. Larger individuals with more or less rostrate apices, in smaller specimens apices more broadly rounded. Valve dimensions (n = 25): length 14.5‒ 22.0 µm, width 6.0‒8.5 µm. Axial area relatively narrow, linear. Central area with a large fascia, rarely reaching the valve margins, due to a series of small areolae bordering the central area near the margins. Isolated pore solitary, round, located close to the valve margin, never connected to a stria. Raphe filiform, straight, with simple, bent proximal raphe endings, away from the isolated pore. Terminal raphe fissures clearly hooked. Striae weakly radiate near the central area, becoming more radiate towards the apices, 22‒24 in 10 µm. Areolae well visible in LM.

Scanning electron microscopy ( Figs 11–12 )

Striae composed of 2‒4 rounded areolae ( Figs 11‒12 ). Occasionally areolae fused within one stria forming transapically enlarged areolae ( Fig. 11 ). Terminal raphe fissures clearly hooked, first deflected towards the side opposite the isolated pore, then hooked into the other side, weakly continuing onto the valve mantle ( Fig. 12 ).

Ecology and associated diatom flora

Luticola beyensii was found in relatively dry, bare soils and on dry mosses (F-value VII-VIII) on both islands. The samples with L. beyensii were dominated by several taxa of the genus Humidophila R.L.Lowe et al. [ Humidophila contenta (Grunow) R.L. Lowe et al. (Lowe et al. 2014) , Humidophila brekkaensis

(J.B.Petersen) R.L. Lowe et al. (Lowe et al. 2014)], and Pinnularia borealis Ehrenb. ( Ehrenberg 1843)

and Hantzschia amphioxys (Ehrenb.) Grunow (Cleve & Grunow 1880) .

Figures

Figs 1–12.Luticola beyensii Vande Vijver et al. Light (LM) and scanning electron micrographs (SEM) of a population from Ile Amsterdam. 1–10. LM of valve face views. 11–12. SEM of external view of entire valve,showing raphe structure, positionof theisolated pore and striaestructure.Scale bars: 1–10 = 10 µm; 11‒12 = 5 µm.