Orthoseira groenlandica Goeyers, Kochman-Kedziora & Van de Vijver 2023, sp. nov.

• Main Authors: Goeyers, Charlotte, Kochman-Kędziora, Natalia, Vijver, Bart Van De
• Format: Other/Unknown Material
• Language: unknown
• Published: Zenodo 2023
• Subjects: Biodiversity; Taxonomy; Chromista; Ochrophyta; Bacillariophyceae; Orthoseirales; Orthoseiraceae; Orthoseira; Orthoseira groenlandica; Greenland; Qeqertarsuaq
• Online Access: https://doi.org/10.5281/zenodo.8143236; http://treatment.plazi.org/id/03D2F8617863FFFA5FA64FA1D70EB72A

Orthoseira groenlandica Goeyers, Kochman-Kędziora & Van de Vijver, sp. nov. (Figs 1–30) Type :— GREENLAND, Qeqertarsuaq, sample DM27 (coll. date 27.VII.2002, 69°15’23.3”N / 53°30’26.5”W, leg. P. Ledeganck), holo-BR-4801! (Meise Botanic Garden, Belgium), iso- slide 428! (University of Antwerp, Belgium). The holotype is represented by Fig. 8. PhycoBank registration :—http://phycobank.org/103791 LM (Figs 1–22): Frustules cylindrical in girdle view, solitary or occasionally in pairs, with their valve faces connected (Figs 1–6, frustules in pairs not shown). Longer filaments of more than two connected frustules up to now not observed. Cells 15–25 μm, mantle height ca. 8 μm. Valves disc-shaped (Figs 7–22). Valve diameter (n=30): 10–35 μm. Valve surface flat, sloping abruptly at the valve face/mantle junction, visible in LM as a darker circular edge. Central area small, max. 1/5 of the total valve diameter, irregular in shape, hyaline, with often scattered areolae present between the carinoportulae. 2–3 (occasionally 4) large, rounded carinoportulae present. No relationship noted between number of carinoportulae and valve diameter. Striae on the mantle uniseriate, composed of densely packed irregular series of areolae, up to 25 in 10 μm. Valve face areolae large, arranged in radiate, uniseriate striae of variable length, 14–18 in 10 µm. Large, scattered marginal spines distinctly present at the valve face/mantle junction. No caverns, internal undulations or internal valves observed. Copulae number variable. (Figs 1–6). SEM (Figs 23–35): Cingulum composed of several broad, open copulae entirely covered with small siliceous papillae (Figs 23, 24) and bearing several irregularly arranged, often incomplete rows of small poroids (Figs 23, 24). Mantle shallow, often with a clear step halfway the valve mantle (Figs 25, arrow, 26) giving the abvalvar mantle edge a thickened appearance compared to the advalvar edge. Marginal pore fields absent. Mantle covered by an irregular pattern of flattened but thickened ridges, giving ...