Psammothidium confusoneglectum Kopalova, Zidarova & Van de Vijver 2016, sp. nov.

• Main Authors: Kopalová, Kateřina, Zidarova, Ralitsa, Vijver, Bart Van De
• Format: Other/Unknown Material
• Language: unknown
• Published: Zenodo 2016
• Subjects: Biodiversity; Taxonomy; Chromista; Bacillariophyta; Bacillariophyceae; Achnanthales; Achnanthidiaceae; Psammothidium; Psammothidium confusoneglectum; Antarc*; Antarctica; Livingston Island; South Shetland Islands
• Online Access: https://doi.org/10.5281/zenodo.3853078; http://treatment.plazi.org/id/03873C46FFC4FFE3FEB64991A1EDFCA3

Psammothidium confusoneglectum Kopalová, Zidarova & Van de Vijver sp. nov. Figs 58–85 Etymology The specific epithet refers to the possible confusion with Psammothidium confusum (Manguin) Van de Vijver. Type Byers Peninsula, Livingston Island, South Shetland Islands, Antarctica, sample BYM-051 (62°38′20.1″S 61°06′44.2″W) (leg. B. Van de Vijver), coll. date: 15 Jan. 2009 (holo-: slide no. BR–4438; iso-: slide PLP–294, University of Antwerp, Belgium). Description Light microscopy (Figs 58–82) Valves broadly elliptic-lanceolate with clearly convex margins gradually tapering towards the broadly rounded, non-protracted apices. Valve dimensions (n = 30): length 9–12 µm, width 3.8–4.5 µm. Raphe valve (Figs 58–70): axial area narrow, linear, not widening towards central area. Central area forming a rectangular to bow-tie-shaped fascia with occasionally one to several shortened striae near the valve margins (Figs 62–64, 68). Raphe straight with almost indistinct, straight proximal endings. Distal fissures not discernible in LM. Transapical striae weakly radiate near the central area, becoming more radiate towards the apices, 30–34 in 10 µm. Areolae not discernible in LM. Rapheless valve (Figs 71–82): axial area very narrow, linear distinctly widening towards the central area. Central area rounded to apically elliptical, bow-tie shaped widening towards the valve margins, almost forming a fascia. Regularly, shortened striae present near the valve margins. Transapical striae weakly radiate throughout becoming more radiate towards the apices, 33–36 in 10 µm. Scanning electron microscopy (Figs 83–85) Raphe valve (Fig. 83): striae uniseriate, composed of small, rounded to rectangular areolae, the largest areolae located close to the axial area. Number of areolae per stria diminishing towards the axial area. Near valve margins, last areola transapically elongated, slit-like. A row of slit-like areolae present on the mantle. Raphe branches almost straight. Proximal raphe endings straight, drop-like expanded (Fig. 83). Distal ...