Navicula escambia
(Patrick) Metzeltin and Lange-Bertalot 2007 Category: Symmetrical biraphid
BASIONYM: Navicula schroeteri var. escambia Patrick 1959
LM scalebar = 10 µm = 80 pixels.
Observations
Contributor: Kalina Manoylov | Paul Hamilton - June 2010
Length Range: 28.1-48.6 µm
Width Range: 6.3-9.1 µm
Striae in 10 µm: 10-13
Description
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.
Original Description
Basionym: Navicula schroeteri var. escambia
Author: Patrick 1959
Length Range: 33-50 µm
Width Range: 7-9 µm
Striae in 10 µm: 12-13
Original Description
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 Images
Original text and images reproduced with permission by Academy of Natural Sciences of Philadelphia.
Cite This Page:
Manoylov, K., and Hamilton, P. (2010). Navicula escambia. In Diatoms of the United States. Retrieved May 22, 2013, from http://westerndiatoms.colorado.edu/taxa/species/navicula_escambia
Species: Navicula escambia
Contributor: Kalina Manoylov | Paul Hamilton
Reviewer: Sarah Spaulding
- Areolae coarse, distinct
- Central area asymmetric
- Valve width 6.3-9.1 µm
- Apices broadly rounded or wedge-shaped
Valves are robust, linear-elliptical with broadly rounded or wedge-shaped apices. The lineolate striae are composed of coarse, distinct areolae. The central area is prominent and asymmetrically rounded. Valves are 6.1-9.1 µm wide.
Compare
Navicula escambia differs from N. schroeteri in shape and valve width; N. schroeteri has wedge-shaped rostrate valve apices and is wider than 9 µm. Navicula escambia is larger (38.7 µm versus 28.8 µm) and lower in stria density than N. symmetrica. Furthermore, the central area of N. escambia is relatively large and distinct compared to the central area of N. symmetrica. The areolae of N. symmetrica are less distinguishable, and the Voigt faults are less distinct than those of N. escambia.
Navicula symmetrica
Navicula schroeteri
Meister
Citations
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.
Links & ID's
Index Nominum Algarum (INA)
California Academy of Sciences (CAS)
North American Diatom Ecological Database (NADED)
NADED ID: