Diploneis zannii J. Frenguelli

Vouilloud, Amelia A., Sala, Silvia E. & Heguilor, Santiago, 2018, Revision of the type material of Diploneis zannii Frenguelli (Bacillariophyceae), Phytotaxa 351 (3), pp. 239-245 : 244

Diploneis zannii J. Frenguelli emend Vouilloud

Emended diagnosis: Valves elliptic-lanceolate, 37.5–57.5 μm length, 27–36 μm breadth. Longitudinal canals occupying 1/3 of valve width, together forming a narrow lanceolate area. Striae uniseriate, slightly radial at valve center, 8–10/10 μm, strongly radial at ends, 10–11/10 μm, interrupted at canals. Transapical ribs fungiform in transverse section. Raphe filiform; external proximal ends straight, located at bottom of a depression; distal ends curved in obtuse angle to same side. Internally raphe straight, running through sunken area between longitudinal canals; proximal and distal ends simple, helictoglossae slightly developed. Longitudinal canals with row of areolae separated from striae by conspicuous hyaline area. Externally, each alveolus opens as a uniseriate stria composed of equidistant areolae, 10–12/10 μm.