Navicula viridula
(Kützing) Ehrenberg 1836 Category: Symmetrical biraphid
BASIONYM: Frustulia viridula Kützing 1833
LM scalebar = 10 µm = 40 pixels.
Observations
Contributor: Marina Potapova - November 2011
Length Range: 50-70 µm
Width Range: 11.2-13.5 µm
Striae in 10 µm: 8-9
Description
Valves are lanceolate to linear-lanceolate with subrostrate apices. The axial area is narrow and straight. The central area is asymmetric; it is trapezoid on the primary side, and semi-circular on the secondary side. The raphe is straight, with external proximal raphe ends slightly dilated and bent toward the primary side of the valve. The central nodule is asymmetrically expanded on the internal valve surface to the primary side. Striae are radiate in the valve center, becoming convergent at the apices. Areolae are usually visible under LM and number 24-25 in 10 μm.
Original Description
Basionym: Frustulia viridula
Author: Kützing 1833
Length Range: µm
Striae in 10 µm:
Original Description
FRUSTULIA VIRIDULA. Ktz. (Fig. 12.) Frustulis minutissimis viridi-lutescentibus, lanceolatis, altero latere truncates, altero acutiusculis, aut opacis aut apicibus hyalines, in strato mucoso nidulantibus. Ich fand sie in einem Teiche bei Markwerben unweit Weissenfels an Hypnum fluitans, so wie auch unter Oscillatorien, mit der folgenden vermischt. Sie bewegte sich.
Original Images
Cite This Page:
Potapova, M. (2011). Navicula viridula . In Diatoms of the United States. Retrieved May 23, 2013, from http://westerndiatoms.colorado.edu/taxa/species/navicula_viridula
Species: Navicula viridula
Contributor: Marina Potapova
Reviewer: Rex Lowe
Image Credit: Marina Potapova
- Valves lanceolate to linear-lanceolate
- Apices subrostrate
- Valves 11.2-13.5 μm wide
- Central nodule asymmmetric
- External proximal raphe ends bent toward primary side
Valves are lanceolate to linear-lanceolate with subrostrate apices. Central area is asymmetric; trapezoid on primary side, semi-circular on secondary side. External proximal raphe ends are slightly dilated and bent toward the primary side of the valve. The central nodule is asymmetrically expanded on the internal valve surface to the primary side. Striae are radiate in the valve center, becoming convergent at the apices.
Compare
Navicula viridula differs from N. viridulacalcis subsp. neomundana the most similar species, by lanceolate valves with distinctly subrostrate apices. Navicula slesvicensis has a symmetric central nodule and straight proximal raphe ends.
Navicula viridulacalcis subsp. neomundana
Navicula slesvicensis
Citations
Ehrenberg, C.G. (1836). Mittheilungen über fossile Infusionsthiere. Bericht über die zur Bekanntmachung geeigneten Verhandlungen der Königlich-Preussischen Akademie der Wissenschaften zu Berlin 1836:50-54.
Kützing, F.T. (1833). Synopsis Diatomacearum oder Versuch einer systematischen Zusammenstellung der Diatomeen. Linnaea 8(5): 529-620, pls. XIII-XIX.
Links & ID's
Index Nominum Algarum (INA)
California Academy of Sciences (CAS)
North American Diatom Ecological Database (NADED)
NADED ID: 46408