Orthoseira verleyenii Van de Vijver 2013, sp. nov.

• Main Authors: Lowe, Rex L., Kociolek, J. Patrick, Vijver, Bart Van De
• Format: Other/Unknown Material
• Language: unknown
• Published: 2013
• Subjects: Biodiversity; Taxonomy; Chromista; Ochrophyta; Bacillariophyceae; Orthoseirales; Orthoseiraceae; Orthoseira; Orthoseira verleyenii; Antarctic; Antarc*; Île Amsterdam
• Online Access: https://zenodo.org/record/5078789; https://doi.org/10.5281/zenodo.5078789

Orthoseira verleyenii Van de Vijver sp. nov. (Figs 1–33) Cells cylindrical forming long chains. Frustules in girdle view 45–95 µm long. Diameter 17–70 µm. Mantle height 15–25 µm. Central area forming a small hyaline zone (max. 1/3 of the total valve diameter). Marginal spines bifurcating, irregularly positioned on the valve face/mantle margin. Areolae on the valve face dispersed or arranged in radiate striae, 15–18 in 10 µm. On the mantle, striae parallel, distinctly areolated, 19–25 in 10 µm. Carinoportulae 1–6, usually 2. Type: — Île Amsterdam, Grand Tunnel, sample AMS-W33 (37°48’47.1”S, 77°33’42.6” E, Leg. B. Van de Vijver, coll. date 04/12/2007), slide no. BR-4309 (holotype BR), slide PLP-224 (isotype University of Antwerp, Belgium). Etymology: —The specific epithet verleyenii refers to my colleague and friend Dr. Elie Verleyen (University of Ghent, Belgium) in recognition of his important contribution to the (paleo-) ecology and biodiversity of Antarctic algae. Observations:—LM (Figs 1–15): Cells cylindrical in girdle view (Figs 1–2), attached with linking spines (Figs 3–5), usually forming large chains, up to 8–10 valves. Cells 45–95 µm, mantle height ca. 15–25 µm. Valves disc-shaped (Figs 6–9), diameter 17–70 µm. Valve surface flat, forming a right angle with valve mantle. Striae on the mantle composed of uniseriate areolae, 19–25 in 10 µm. Valve face areolae small, radiate, irregularly scattered, rarely forming continuous series, occupying almost 2/3 of the total valve face surface, with remaining surface forming an irregular, small central hyaline area. Towards the valve centre, areolae more scattered, 15–18 areolae in 10 µm, irrespective of valve size. Central area with 1–6 carinoportulae (Figs 10–15) (for 100 valves, 48 % with only two, 23 % with three, 24 % with four and only 1–3% with one, five or six carinoportulae). No relationship noted between number of carinoportulae and valve diameter. Distinct ring of marginal linking spines at the valve face/mantle junction. No caverns or internal ...