Navicula escambia

(R.M.Patrick) Metzeltin and Lange-Bert. 2007      Category: Symmetrical biraphid
BASIONYM: Navicula schroeteri var. escambia R.M.Patrick 1959

Navicula erifuga


Navicula flatheadensis

LM scalebar = 10 µm = 80 pixels.


Contributor: Kalina Manoylov | Paul Hamilton - June 2010
Length Range: 28-49 µm
Width Range: 6.3-9.1 µm
Striae in 10 µm: 10-13


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: R.M.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 April 24, 2018, from

Species: Navicula escambia

Contributor: Kalina Manoylov | Paul Hamilton

Reviewer: Sarah Spaulding


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)

Original INA

California Academy of Sciences (CAS)

Navicula escambia CAS

North American Diatom Ecological Database (NADED)


Autecology Discussion

EMAP Assessment

The Environmental Protection Agency (EPA) western Environmental Monitoring and Assessment Program (EMAP) study was completed during the years 2000-2004 (see citations at bottom of this page). Over 1200 streams and rivers in 12 western states (Arizona, California, Colorado, Idaho, Montana, Nevada, North Dakota, Oregon, South Dakota, Utah, Washington and Wyoming) were selected for sampling based on a stratified randomized design. This type of design insures that ecological resources are sampled in proportion to their actual geographical presence. Stratified randomized design also allows for estimates of stream length with a known confidence in several “condition classes” (good or least-disturbed, intermediately-disturbed, and poor or most-disturbed) for biotic condition, chemistry and habitat.

EMAP Distribution

Navicula escambia

EMAP Response Plots

Navicula escambia

EMAP citations

Results are published in:

Johnson, T., Hermann, K., Spaulding, S., Beyea, B., Theel, C., Sada, R., Bollman, W., Bowman, J., Larsen, A., Vining, K., Ostermiller, J., Petersen, D. Hargett, E. and Zumberge, J. (2009). An ecological assessment of USEPA Region 8 streams and rivers. U.S. Environmental Protection Agency Region 8 Report, 178 p.

Stoddard, J. L., Peck, D. V., Olsen, A. R., Larsen, D. P., Van Sickle, J., Hawkins, C. P., Hughes, R. M., Whittier, T. R., Lomnicky, G. A., Herlihy, A. T., Kaufman, P. R., Peterson, S. A., Ringold, P. L., Paulsen, S. G., and Blair, R. (2005). Environmental Monitoring and Assessment Program (EMAP) western streams and rivers statistical summary. U.S. Environmental Protection Agency Report 620/R-05/006, 1,762 p.

Stoddard, J. L., Peck, D. V., Paulsen, S. G., Van Sickle, J., Hawkins, C. P., Herlihy, A. T., Hughes, R. M., Kaufman, P. R., Larsen, D. P., Lomnicky, G. A., Olsen, A. R., Peterson, S. A., Ringold, P. L., and Whittier, T. R. (2005). An ecological assessment of western streams and rivers. U.S. Environmental Protection Agency Report 620/R-05/005, 49 p.