Pinnularia australoborealis Van de Vijver & Zidarova 2011, sp. nov.

• Main Authors: Vijver, Bart Van De, Zidarova, Ralitsa
• Format: Other/Unknown Material
• Language: unknown
• Published: 2011
• Subjects: Biodiversity; Taxonomy; Chromista; Bacillariophyta; Bacillariophyceae; Naviculales; Naviculaceae; Pinnularia; Pinnularia australoborealis; Byers; Byers peninsula; Livingston Island; Ross Island; Sickle; South Shetland Islands; James Ross Island
• Online Access: https://zenodo.org/record/4918049; https://doi.org/10.5281/zenodo.4918049

Pinnularia australoborealis Van de Vijver & Zidarova, sp. nov. (Figs 18–25) Valvae stricte lanceolatae marginibus convexibus, apicibusque truncatis, subrostratis. Dimensiones (n=15): longitudo 51–61 µm, latitudo 12.5–14.0 µm, ratio longitudinis/latitudinis 3.9–4.3. Area axialis moderate angusta, linearislanceolata, 1/6 latitudinis valvae, leviter dilatans ad aream centralem. Area centralis paene rotundata ad rectangularis. Fascia abest. Raphe moderate lateralis. Rami externi raphis leviter ad distincte curvati. Terminationes proximales leviter unilateraliter deflexae, in summa reflexae ad paene rectae. Fissurae distales unciformes. Striae transapicales latae, leviter ad moderate radiatae in media parte valvae, ad parallelae in apices, 4–5 in 10 µm. Valves moderately large, strictly lanceolate with convex margins and subrostrate, truncated apices. Valve dimensions (n=15): length 51–61 µm, width 12.5–14.0 µm, length/width ratio 3.9–4.3. Axial area moderately narrow, linear-lanceolate, 1/6 of the valve width, slightly widening towards central area. Central area almost rounded (see, for instance, Fig. 20) to mostly rectangular, lacking fascia, since asymmetrically bordered by 1– 3 shortened striae on each side. Raphe moderately lateral, with outer raphe branches weakly to distinctly curved. Proximal raphe endings slightly unilaterally deflected but at end reflected to almost straight (Fig. 25), terminating pore-like. Distal fissures typically sickle-shaped. Transapical striae broad, weakly to moderately radiate in middle to parallel near apices, 4–5 in 10 µm. Type:— Byers Peninsula, Livingston Island, South Shetland Islands, sample LIV16 A, leg. A. Quesada, coll. date 16/12/2006, slide no. BR-4233 (holotype BR), slide PLP-183 (isotype University of Antwerp, Belgium), BRM-7/96 (isotype BRM). Habitat and Distribution: —On Byers Peninsula, Pinnularia australoborealis was only observed in some samples taken in flooded algal mats, living between stones. It was also observed on James Ross Island, situated in the ...