Ctenophora subula (Sande Lac. & Suringar) D.M.Williams & Van de Vijver, 2023

Williams, David M. & Vijver, Bart Van De, 2023, An electron microscope study and re-description of the type specimens of Synedra subula and its transfer to Ctenophora (Bacillariophyta), Phytotaxa 629 (2), pp. 176-180 : 178

Ctenophora subula (Sande Lac. & Suringar) D.M.Williams & Van de Vijver nov. comb.

Registration: http://phycobank.org/103733

Basionym:— Synedra subula Sande Lac. & Suringar 1861a Nederlandsch Kruidkundig Archief 5 (2): 289.

TYPE:— THE NETHERLANDS, Zwindersche Veld, Drenthe (“Op Cladophora Sandii, Zwindersche Diep. D. 34”), L 4111638 , https://data. biodiversitydata.nl/naturalis/specimen/L.4111638, Figure 2 = lectotype designated here .

VaLves LanceoLate,but gentLY taPering towards botH PoLes; LengtH ca. 65–80μm, widtH ca. 2–5μm ( Figure 3 ,measurements taken from pole and centre, n = 8). Sternum relatively narrow, linear, regular, slightly narrowing towards poles, becoming slightly irregular towards each pole ( Figures 5, 7, 8, 10 ). Sternum meeting square to oblong shaped ‘central area’, heavily buttressed both sides of valve ( Figures 4, 7 ); buttressing composed of modified virgae enclosing clear hyaline area (= ‘central area’), ‘ghost striae’ faint ( Figures 4, 7 ). Sternum meeting and coalescing with virgae, both ca. same size, vimines reduced in size relative to virgae ( Figures 4, 5, 7–9, 10 ), appearing as mesh-work with ca. 8–12 strutted cLosing PLate. Striae (= virgae + vimines) 13–14 (?) in 10μm, areoLae ca. 20 (?) in 10μm, reguLarLY sPaced, parallel ( Figures 5, 7, 8 ), extending onto mantle, in 2–4 ‘rows’ ( Figure 7 ). Apical pore field as ocellulimbus (sunken pore field), composed of ca. 6 rows/columns of pores, situated entirely on valve mantle ( Figure 6 ). Spines absent, rimoportulae at both poles, simple, composed of (internally) paired lips situated on or adjacent to virgae, externally occurring between virgae, one at each pole ( Figures 3, 8, 10 ). Girdle composed of at least one open band, VC ( Figure 11 ), with series of areolae similar to those on valve, occurring just below surface of valve mantle, crenulated edge to fit virgae.

Figures

Figures 1, 2.

Figures 3–11. Ctenophora subula SEM images