Fragilaria candidagilae Almeida, C.Delgado, Novais & S.Blanco, 2015

De, Bart Van, Vijver, Mertens, Adrienne & Ector, Luc, 2020, Analysis of the type material of Synedra deformis W. Sm. and Synedra vaucheriae var. deformis Grunow (Fragilariaceae, Bacillariophyta), Cryptogamie, Algologie 20 (13), pp. 137-149 : 142-143

Fragilaria candidagilae Almeida, C.Delgado, Novais & S.Blanco , type population

( Fig. 3 )

Basionym: Fragilaria candidagilae Almeida, C.Delgado, Novais & S.Blanco in Delgado et al., Phytotaxa 231: 3, figs 2-39 (2015).

MORPHOLOGY

LM ( Fig. 3 A-R)

Frustules in girdle view rectangular, solitary or two cells linked together (Fig. 48). Valves elliptic-lanceolate with convex or parallel margins in larger specimens, strictly convex margins in smaller valves. Valves occasionally irregularly shaped. Shoulders distinctly developed with clearly protracted, capitate to rostrate (in smaller specimens) apices. Valve dimensions (n = 25): valve length 11-23 µm, valve width 4-5 µm. Axial area very narrow linear, almost not widening towards the central area. Central area small, clearly asymmetrical due to absence or shortening of striae on one side, forming an asymmetrical fascia. Striae parallel throughout, becoming weakly radiate near the apices, 12-14 in 10 µm, often irregularly spaced. Areolae not discernible in LM.

SEM ( Fig. 3 S-W)

Girdle composed of several open, perforated copulae ( Fig. 3S ). Large, irregularly shaped mantle plaques present on the mantle edge ( Fig. 3S ). Mantle striae continuing from the valve face till halfway the mantle edge ( Fig. 3S ). Striae uniseriate, composed of very small, rounded areolae ( Fig. 3 T-U). Virgae between the striae very weakly raised to flat ( Fig. 3V ). One rimoportula present at one apex, in line with the before last stria at the apex ( Fig. 3 T-V). Apical pore field present at both apices, relatively large, composed of up to five rows of relatively large, rounded to squarish pores ( Fig. 3V ). Spines never present. Internally, rimoportula distinctly present at one apex, superimposed on one of the final striae at the apex, weakly oblique ( Fig. 3W ).

Figures

FIG. 3. — Fragilaria candidagilae Almeida, C.Delgado, Novais & S.Blanco.Images taken from the type material (Ribeira do Botão, Mondego River Basin, Coimbra Portugal): A, LM view of two frustules connected in girdle view;B-R, LM views of the population arranged in decreasing length; S, SEM external view of a frustule in girdle view showing the girdle bands, the apical pore fields and the mantle plaques; T, SEM external view of an entire valve; U, SEM external view of an entire small valve; V, SEM external detail of a valve apex with the rimoportula and the apical pore field; W, SEM internal view of an entire valve showing the slightly eccentric position of the rimoportula at one apex. Scale bars: A-U, W, 10 µm; V, 1 µm.