Frustules are flat, almost always coming to rest in valve view due to shallow mantles (1.5-2.0 µm deep). Valves are broadly lanceolate with acutely rounded ends in all but the smallest specimens. The axial area is narrow. Central area is broad, rectangular and reaches nearly to the valve margins. A single, shortened stria is present on each side. External raphe fissures are straight and threadlike. Proximal raphe ends are slightly inflated and relatively distant from one another. Terminal raphe fissures are bent diagonally toward the valve margin and are characteristically in close contact with a single areola at each apex, making the raphe fissures appear as hook-like terminations. Striae are broad, lineate, radiate and slightly curved about the central area. The striae extend onto the valve mantle. A crown of small areolae of different shapes are present at each valve apex. Striae are parallel or slightly convergent toward the valve apices.
Basionym: Navicula goersii
Author: Bahls 1983
Length Range: 8-14 µm
Width Range: 3-4 µm
Striae in 10 µm: 14-16
Valvae late lanceolatae, apicibus angustatis usque ad rostellatos. Area axialis angustata. Area centralis latus, rectangularis, extensus fere ad marginem valvarum, unus abbreviatus stria in uterque latus. Raphe rectus, filiformis. Striae latae, lineolatae, radiatae et leviter curvae circa area centralis, parallelae vel leviter connivens ad apices, 14 (medium) ad 16 (apices) in 10 µm. Longitudo, 8-14 µm (typice 12 µm). Latitudo, 3-4 µm (typice 3.5 µm).
Cite This Page:
Bahls, L., Morales, E., and Potapova, M. (2011). Navicula goersii. In Diatoms of the United States. Retrieved July 29, 2015, from http://westerndiatoms.colorado.edu/taxa/species/navicula_goersii
Species: Navicula goersii
Reviewer: Rex Lowe
Bahls, L.L. (1983). A new diatom from southeastern Montana. Proceedings of the Montana Academy of Sciences 42: 1-6.
NADED ID: 93175
Most records of Navicula goersii are from streams in the semi-arid West and only a few are from the eastern United States. Navicula goersii prefers nutrient-rich alkaline waters with somewhat elevated conductance (see table below). These waters are typical of the sagebrush and grassland prairies of the western United States. Common diatom associates of N. goersii are Diploneis puella, Navicula caterva, Biremis circumtexta, Navicula canalis, Fallacia tenera, Nitzschia reversa, and Pleurosigma delicatulum.
Abundance-weighted means of selected water quality variables measured concurrently with the collection of samples containing *Navicula goersii”.
Credit/Source: Montana Diatom Database