(Patrick) Metzeltin and Lange-Bertalot 2007 Category: Symmetrical biraphid
BASIONYM: Navicula schroeteri var. escambia Patrick 1959
Valves are linear-elliptical with rounded apices. Valve measurements: length 28.1-48.6 µm, width 6.3-9.1 µm with 12-13 striae per 10 µm. Axial area is narrow, linear and distinct; a distinct central nodule is present. The central area is asymmetrically rounded, wider on the secondary side of the valve. In LM, the raphe is filiform with enlarged proximal raphe ends deflected towards the primary side of the valve, and distal fissures are distinctly hooked towards the primary side extending from the valve face onto the mantle. Striae are radiate. The space between the striae is equal to or less than the width of the striae. Voigt faults are not easily evident. Areolae are lineate and apically aligned to form the appearance of continuous curving lines around the central area.
Basionym: Navicula schroeteri var. escambia
Author: Patrick 1959
Length Range: 33-50 µm
Width Range: 7-9 µm
Striae in 10 µm: 12-13
Valva lineari apicibus late rotundatis. Area axiali angusta et distincta. Fissuris terminalibus raphis intortis et in eadem directione. Area centrali magna, plus aut minus ellipticali in forma. Striis lineatis distincte facientibus lineas longitudinales obscuras. Striis transversis radiatis, leniter incurvis, 13 in 10 µ. Longitudo, 33-50 µ (specimen typicum, 45.5 µ). Latitudo, 7-9 µ (specimen typicum, 8.5 µ). Striae. 12-13 in 10 µ.
Valve linear with broadly rounded ends. Axial area narrow, distinct. Terminal fissures of raphe turned to one side, and in the same direction. Central area large, more or less elliptical in shape. Striae distinctly lineate, forming indistinct longitudinal lines. Transverse striae radiate, slightly curved, 13 in 10 µ. Length, 33-50 µ (type 45.5 µ). breadth, 7-9 µ (type 8.5 µ). Striae, 12-13 in 10 µ.
This variety differs from the nominate variety in that the ends of this taxon are broadly rounded rather than bluntly acute. The central area is elliptical in this variety, whereas in the nominate variety it is rectangular. This species is related to N. pavillardi Hust. [Abh. Naturw. Ver. Bremen 31(3):635, figs 86-90, 1939]. it is similar to Navicula symmetrica Patrick (Bol. Mus. Nac. Brasil. Bot. Nov. Ser. No 2, p.5, fig.6, 1944) but differs in the striae being coarser and more coarsely lineate. Specimen illustrated-A G.C.6564A (holotype). Type locality.- Florida, Santa Rosa County, Escambia river, eight to nine miles from the mouth, R. Patrick, 1952. Distribution: United States-Florida- Santa Rosa County- Escambia river near Pensacola. TEXAS-Orange county- Sabine River near Orange.
Original text and images reproduced with permission by Academy of Natural Sciences of Philadelphia.
Metzeltin, D. and Lange-Bertalot, H. (2007). Tropical Diatoms of South America II. Iconographia Diatomologica 18, 1-877.
Patrick, R.M. (1959). New species and nomenclatural changes in the genus Navicula (Bacillariophyceae). Proceedings of the Academy of Natural Sciences of Philadelphia, 111, 91-108.