Navicula pseudolanceolata
Lange-Bertalot 1980 Category: Symmetrical biraphid
BASIONYM: Navicula pseudolanceolata Lange-Bertalot 1980
LM scalebar = 10 µm = 40 pixels.
Observations
Contributor: Loren Bahls - December 2011
Length Range: 41-59 µm
Width Range: 9.0-11.1 µm
Striae in 10 µm: 9-11
Description
Valves are lanceolate, with acutely pointed apices in smaller specimens and weakly protracted, narrowly rounded apices in larger specimens. The axial area is narrow, widening into a small rhombic central area. The raphe is weakly lateral and essentially straight, with relatively distant and only slightly expanded proximal ends. Striae are irregularly shortened and more widely spaced about the central area, strongly radiate and mostly straight, becoming parallel, but not convergent at the valve apices. Lineolae are coarse and number 24 in 10 µm.
Original Description
Basionym: Navicula pseudolanceolata
Author: Lange-Bertalot 1980
Length Range: 30-50 µm
Width Range: 7-9.5 µm
Striae in 10 µm: 9.5-11
Original Description
Valves lanceolate to rhombic-lanceolate, ends gradually narrowed, wedge-shaped, length 30-50 microns, breadth 7-9.5 microns. Raphe weakly lateral, axial area narrow, central area small to moderately larger, slightly rhombic to transversely widened. Striae strongly radiate throughout or parallel at the ends, 9.5-11/10 microns; lineolae appear coarse, c. 24/10 microns.
Original Images
Cite This Page:
Bahls, L. (2011). Navicula pseudolanceolata. In Diatoms of the United States. Retrieved May 23, 2013, from http://westerndiatoms.colorado.edu/taxa/species/navicula_pseudolanceolata
Species: Navicula pseudolanceolata
Contributor: Loren Bahls
Reviewer: Marina Potapova
Image Credit: Loren Bahls
- Valves lanceolate
- Apices protracted
- Apices with radiate or parallel striae
- Center valve with straight striae
Valves are lanceolate and 8-11 µm in width. Apices are narrow and protracted, except in small specimens. The striae near the apices are variable; they may be radiate or parallel. The striae near the center of the valve are straight, rather than bent.
Compare
Navicula pseudolanceolata has narrower apices, a smaller and more irregular central area, and coarser areolae than N. lanceolata. Terminal striae are radiate to parallel in N. pseudolanceolata and convergent in N. lanceolata. Navicula subconcentrica has more attenuated apices and more closely set proximal raphe ends than N. pseudolanceolata. Navicula flatheadensis has larger valves, weakly protracted apices in smaller specimens, striae that are bent near the central area and parallel to weakly convergent at the apices.
Navicula flatheadensis
Navicula lanceolata
Navicula subconcentrica
Citations
Lange-Bertalot, H. (1980). Zur taxonomischen Revision einiger ökologisch wichtiger “Navicula lineolatae” Cleve. Die Formenkreise um Naviculae lanceolata, N. viridula, N. cari. Cryptogamie, Algologie 1(1):29-50.
Lange-Bertalot, H. (2001). Navicula sensu stricto, 10 genera separated from Navicula sensu lato, Frustulia. Diatoms of Europe 2: 1-526.
Links & ID's
Index Nominum Algarum (INA)
California Academy of Sciences (CAS)
North American Diatom Ecological Database (NADED)
NADED ID: 46153
Autecology Discussion
There are 82 records of Navicula pseudolanceolata in the Montana Diatom Collection, from lakes and streams in mountain regions of the Northwest United States. The species is rarely found in abundance. Specimens pictured here are from Lower Branham Lake in the Tobacco Root Mountains of southwest Montana. At the time of sampling this lake had a pH of 8.74 and specific conductance of 64 µS/cm. Lange-Bertalot (2001) reports N. pseudolanceolata from low conductivity or weakly humic acid and oligotrophic lakes in Europe.
Images
Lower Branham Lake, Madison County, Montana: home of Navicula pseudolanceolata.
Credit/Source: Loren Bahls