Stauroneis schinzii var. maxima Frenguelli

Vouilloud, A. A., Guerrero, J. M., Palladino, M. B. & Lamaro, A. A., 2021, Revision Of The Type Materials Of Stauroneis Schinzii Var. Argentina Frenguelli And S. Schinzii Var. Maxima Frenguelli (Bacillariophyceae), Phytotaxa 478 (1), pp. 119-130 : 128

Stauroneis schinzii var. maxima Frenguelli emend Guerrero & Vouilloud

Emended diagnosis: Valves linear and robust, 210–237 µm length and 18.2–21 µm width, slightly widened in the middle, with ends broadly rounded and slightly protracted. Pseudosepta absent. Axial area straight, moderately wide and bordered by irregularly long striae. Central area expanded into a relatively narrow, stauros, moderately broadening to the margins and internally thickened. Raphe oblique, filiform towards the ends, laying between two internal longitudinal thickenings of the sternum; external proximal endings drop-like expanded and unilaterally deflected, internal endings simple and straight; distal fissures externally extended and hooked, internally terminating in weakly developed helictoglossae. Striae uniseriate, 13–15 in 10 µm, radiate at the centre and parallel to slightly convergent towards the poles; areolae rounded or transapically elongated, 15–20 in 10 µm, continuous onto the valve mantle.