Pinnularia pinseeliana Zidarova, Kopalová & Van de Vijver, 2016

Zidarova, Ralitsa, Kopalová, Kateřina & Vijver, Bart Van De, 2016, Ten new Bacillariophyta species from James Ross Island and the South Shetland Islands (Maritime Antarctic Region), Phytotaxa 272 (1), pp. 37-62 : 48-49

Pinnularia pinseeliana Zidarova, Kopalová & Van de Vijver , sp. nov. ( Figs 119–135 )

LM observations ( Figs 119–131 ): Frustules in girdle view rectangular ( Fig. 119 ). Valves narrowly lanceolate with weakly but still markedly convex, never parallel margins. Apices non ( Figs 130, 131 ) to weakly protracted ( Figs 120, 125 ), never capitate nor rostrate, broadly rounded. Valve dimensions (n=25): length 24–30 μm, width 4.5–5.5 μm. Axial area narrow near the apices, gradually but distinctly widening towards the central area. Central area large, forming a rectangular (rarely) to wedge-shaped (mostly) fascia. Raphe lateral, with straight to weakly curved branches. Proximal raphe endings clearly expanded, drop-like, unilaterally deflected. Distal raphe fissures elongated, hooked. Striae strongly radiate near the central area, becoming convergent near the apices, 13–15 in 10 μm. Striae near the central area shortened. Longitudinal lines absent. SEM observations ( Figs 132–135 ): Striae externally covered by hymena ( Fig. 132 ). Alveoli composed of 6–7 rows of small areolae ( Fig. 133 ). Raphe curved. Proximal raphe endings drop-like, deflected ( Fig. 132 ). Distal fissures elongated, continuing onto the mantle ( Fig. 132 ). Internally, raphe continuous over the central nodule due to siliceous flap covering the proximal endings ( Fig. 134 ). Distal endings terminating on short helictoglossae ( Fig. 134 ). Alveoli opening via a small elliptic fenestra to the valve interior, showing 6–7 rows of small, rounded areolae ( Figs 134, 135 ). Between the alveoli, virgae bearing elevated siliceous outgrowths ( Fig. 135 , arrows).

Type: — ANTARCTICA. South Shetland Islands: Deception Island, sample CC 2 (62° 58’ 24.0” S, 60° 42’ 30.0” W), G. Mataloni, February 2002 (holotype BR! 4456, isotype PLP! 310).

Etymology: —The species is named after Drs. Eveline Pinseel in recognition of her important scientific contributions to the taxonomy and morphology of the genus Pinnularia , more specifically the Pinnularia borealis -complex.

Ecology and confirmed distribution: — Pinnularia pinseeliana is a rare species and only found in some soil samples on Deception Island (South Shetland Archipelago). The largest population was observed in a warm soil at Cerro Caliente. The soil had a temperature of 19.1 °C and was further characterized in having a weakly acid pH (6.3), a very low conductivity (50 μS/cm) and a rather high amount of organic matter (6.5%) ( Fermani et al. 2007).

Family Sellaphoraceae

Genus Sellaphora Mereschkowsky (1902: 186)

Figures

FIGURES 119–135. Pinnularia pinseeliana sp. nov. LM & SEM pictures taken from the holotype population (sample CC2) from Deception Island (South Shetland Islands).119–131. LM views of 13 valves from the type population. Fig. 119 shows the girdle view. 132. SEM of an entire valve, external view. 133. SEM detail of the valve externally, showing the alveoli of the striae. 134. SEM of entire valve, internal view. 135. SEM detail of the valve interior.Arrows showing the elevated siliceous outgrowths on the virgae. Scale bar represents 10 μm except for figs 133 and 135 where scale bar = 1 μm.