Sellaphora nigri
(De Not.) Wetzel and Ector 2015 Category: Symmetrical biraphid
BASIONYM: Navicula nigri De Not. 1872
REPORTED AS: Eolimna minima (Moser et al. 1998, Bibliotheca Diatomologica, vol. 38, p. 153)
LM scalebar = 10 µm = 80 pixels.
Observations
Contributor: Alison Minerovic - May 2016
Length Range: 4-13 µm
Width Range: 2.8-4.2 µm
Striae in 10 µm: 26-32
Description
Cells small, elliptic to oval, with broadly rounded apices. Striae radiate and uniseriate throughout. Striae bordering central area slightly curved. Shorter striae present in middle of valve forming irregular and asymmetric “bow-tie” shaped to irregularly squared central area. Axial area linear, widening slightly toward the central area. Raphe straight with proximal raphe ends tear-drop shaped. Internally, distal raphe fissures end in small helictoglossae. Areolae vary in diameter and shape. Usually, areolae closest to raphe are larger and slightly angular, becoming smaller and more rounded towards margins. Areolae occluded internally.
Original Description
Basionym: Navicula nigri
Author: De Not. 1872
Length Range: ~10 µm
Striae in 10 µm:
Original Description
Original Images
Cite This Page:
Minerovic, A. (2016). Sellaphora nigri. In Diatoms of the United States. Retrieved April 23, 2018, from http://westerndiatoms.colorado.edu/taxa/species/sellaphora_nigri
Species: Sellaphora nigri
Contributor: Alison Minerovic
Reviewer: Eduardo A. Morales
Image Credit: Alison Minerovic
- Valves elliptic to oval
- Striae radiate
- Striae uniseriate
- Central area asymmetric and 'bow-tie' shape to irregular
- Areolae near sternum larger
Cells small, elliptic to oval, with broadly rounded apices. Striae radiate and uniseriate throughout, with shorter striae present in middle of valve forming irregular and asymmetrical ‘bow-tie’ shaped to irregularly squared central area.
Compare
Sellaphora nigri is morphologically very similar to S. atomoides, and many specimens may not be distinguished from one another in LM. In general, S. nigri is wider, more elliptic, with longer central striae resulting in a less distinct ‘bow-tie’ shaped central area. Additionally, S. nigri is more widely distributed and pollution-tolerant, while S. atomoides is considered indicative of more ‘pristine’ conditions. Sellaphora saugerresii is biseriate (although this feature is not visible in LM) and has a lower stria density.
Sellaphora atomoides
Sellaphora saugerresii
Citations
Wetzel, C.E., Ector, L., Van de Vijver, B., Compère, P. and Mann, D.G. (2015). Morphology, typification and critical analysis of some ecologically important small naviculoid species (Bacillariophyta). Fottea, Olomouc 15(2): 203–234. 10.5507/fot.2015.020
Links & ID's
Index Nominum Algarum (INA)
California Academy of Sciences (CAS)
North American Diatom Ecological Database (NADED)
NADED ID: 170135
Autecology Discussion
Sellaphora nigri is considered to be widely distributed and pollution-tolerant.