Pinnularia laterotundata 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 laterotundata; South Shetland Islands; Ross Island; Livingston Island; Byers; Byers peninsula; Sickle; Limnopolar Lake; James Ross Island
• Online Access: https://zenodo.org/record/4894388; https://doi.org/10.5281/zenodo.4894388

Pinnularia laterotundata Van de Vijver & Zidarova, sp. nov. (Figs 39–44) Valvae moderate grandes, lineares marginibus stricte parallelis, apicibusque late rotundatis, numquam protractis. Dimensiones (n=8): longitudo 44–55 µm, latitudo 11.5–13.5 µm, ratio longitudinis/latitudinis 3.6–4.2. Area axialis potius angusta, linearis-lanceolata, 1/6–1/7 latitudinis valvae, leviter dilatans ad aream centralem. Area centralis rectangularis. Fascia abest. Raphe moderate lateralis. Rami externi raphis moderate curvati. Terminationes raphis proximales leviter unilateraliter deflexae. Fissurae distales unciformes. Striae transapicales latae, leviter radiatae in media parte valvae, ad parallelae in apices, (4) 5–6 in 10 µm. Valves moderately large, linear with strictly parallel margins and broadly rounded, never protracted apices. Valve dimensions (n=8): length 44–55 µm, width 11.5–13.5 µm, length/width ratio 3.6–4.2. Axial area rather narrow, linear-lanceolate, 1/6–1/7 of valve width, slightly widening towards central area. Central area rectangular, lacking fascia since asymmetrically bordered by 2–3 shortened striae on each side. Raphe moderately lateral with outer raphe fissures moderately curved. Proximal raphe endings unilaterally slightly deflected, pore-like. Distal fissures sickle-shaped. Transapical striae broad, weakly radiate in middle to parallel near apices, (4–) 5–6 in 10µm. Type:— Byers Peninsula, Livingston Island, South Shetland Islands, sample BYS012, leg. B. Van de Vijver, coll. date 14/01/2009, slide no. BR-4235 (holotype BR), slide PLP-185 (isotype University of Antwerp, Belgium), slide BRM-7/98 (isotype BRM). Habitat and Distribution:— Pinnularia laterotundata is quite rare on Livingston Island and only found in a few samples from Byers Peninsula. The largest population was observed between small stones in a seepage area near Limnopolar Lake, continuously moistened by flowing water. It was also observed on James Ross Island (Van de Vijver & Kopalová, unpubl. results). Etymology:—The specific ...