Navicula oppugnata
Hustedt 1945 Category: Symmetrical biraphid
BASIONYM: Navicula oppugnata Hustedt 1945
LM scalebar = 10 µm = 40 pixels.
Observations
Contributor: Loren Bahls - October 2012
Length Range: 29-41 µm
Width Range: 8.6-10.1 µm
Striae in 10 µm: 9-11
Description
Valves are lanceolate with obtusely rounded apices. Axial area is narrow and completely filled by the lateral raphe. Central area is small and irregular, typically bordered by alternately short-long-short striae on one or both sides. The distinctly lateral raphe becomes reverse lateral near the proximal ends, which are bent to the secondary side and distinctly inflated. Striae are radiate, becoming parallel to weakly convergent near the apices. Areolae are coarse and number 24-26 in 10 µm.
Original Description
Basionym: Navicula oppugnata
Author: Hustedt 1945
Length Range: 44 µm
Width Range: 10 µm
Striae in 10 µm: 12
Original Description
Schalen lanzettlich mit kaum merklich vorgezogenen, ziemlich spitz gerundeten Enden, um 44 µ lang, etwa 10 µ breit. Raphe gerade, mit etwas seitlich abgebogenen Zentralporen, Axialarea schmal linear, um den Zentralknoten plötzlich zu einer kleinen, querelliptischen Zentralarea erweitert. Transapikalstreifen im mittleren Teil radial und mit vereinzelten eingeschobenen kürzeren Streifen, an den Enden senkrecht zur Mittellinie, 12 in 10 µ, grob liniert, Längslinien etwa 25 in 10 µ, dem Schalenrand annähernd parallel, um den Zentralknoten nach aussen konvexe Bogen bildend.
Original Images
Cite This Page:
Bahls, L. (2012). Navicula oppugnata. In Diatoms of the United States. Retrieved June 18, 2013, from http://westerndiatoms.colorado.edu/taxa/species/navicula_oppugnata
Species: Navicula oppugnata
Contributor: Loren Bahls
Reviewer: Marina Potapova
Image Credit: Loren Bahls
- Valves lanceolate
- Proximal raphe ends bent to secondary side
- Striae coarse
- Areolae coarse
Navicula oppugnata has lanceolate valves, wider than 8 µm. Proximal raphe ends are bent to the secondary side of the valve. Striae are coarse and number 9-11 in 10 µm. Arolae are also coarse, easily resolved in LM and number 24-26 in 10 µm.
Compare
Navicula lundii has a similarly shaped valve and central area, but it is smaller, has straight proximal raphe ends and a higher stria and areola density.
Navicula lundii
Citations
Hustedt, F. (1945). Diatomeen aus Seen und Quellgebieten der Balkan-Halbinsel. Archiv für Hydrobiologie 40(4):867-973.
Lange-Bertalot, H. (2001). Navicula sensu stricto, 10 genera separated from Navicula sensu lato, Frustulia. Diatoms of Europe 2: 1-526.
Simonsen, R. (1987). Atlas and Catalogue of the Diatom Types of Friedrich Hustedt. J. Cramer, Berlin & Stuttgart 1: 525 pp.
Links & ID's
Index Nominum Algarum (INA)
California Academy of Sciences (CAS)
North American Diatom Ecological Database (NADED)
NADED ID: 46979
Autecology Discussion
These images are from a population living in Sheridan Lake in the Black Hills National Forest, western South Dakota. Here, on the sample date, pH measured 9.73 and specific conductance measured 327 µS/cm. Lange-Bertalot (2001) reports this taxon from eutrophic to mesotrophic, calcium-rich standing waters in Europe. This taxon has been recorded infrequently in the United States.