Nupela tenuicephala

(Hust.) Lange-Bert. 1993      Category: Symmetrical biraphid
BASIONYM: Navicula tenuicephala Hust. 1942

REPORTED AS: Stauroneis gracillima (Hustedt 1943, p. 154, figs 21-23) | Stauroneis gracillima (Krammer and Lange-Bertalot 1986, p. 248, pl 90, figs 28-30) | Nupela gracillima (Lange-Bertalot 1993, p. 158) 

Nupela subrostrata


Nupela vitiosa

LM scalebar = 10 µm = 80 pixels.


Contributor: Loren Bahls - May 2016
Length Range: 11-16 µm
Width Range: 2.7-3.3 µm
Striae in 10 µm: 50-60


Valves are linear-lanceolate and weakly dorsiventral, with capitate apices. Valve margins are usually straight and parallel. Some specimens may have a slightly convex ventral margin, while others may have a concave ventral margin. The axial area is very narrow. The central area is an asymmetric, nearly rectangular fascia that is a bit wider on the dorsal side of the valve. SEM images show that the central area does not quite reach the valve margins and is bordered by short striae. A filiform raphe, with tear-shaped proximal raphe ends is present on both valves. Striae cannot be resolved under light microscopy.

Hustedt described two taxa - Navicula tenuicephala (from a lake in Swedish Lapland) and Stauroneis gracillima (from a lake in the central Alps) which I considered to be conspecific and present here as Nupela tenuicephala.

Original Description

Basionym: Navicula tenuicephala
Author: Hust. 1942
Length Range: µm
Striae in 10 µm:

Original Description

Original Images

Cite This Page:
Bahls, L. (2016). Nupela tenuicephala. In Diatoms of the United States. Retrieved April 25, 2018, from

Species: Nupela tenuicephala

Contributor: Loren Bahls

Reviewer: Marina Potapova


Hustedt, F. (1942). Diatomeen aus der Umgebung von Abisko in Schwedisch-Lappland. Archiv für Hydrobiologie 39(1): 87-174 .

Hustedt, F. (1943). Die Diatomeenflora einiger Hochgebirgsseen der Landschaft Davos in den schweizer Alpen. Internationale Revue der gesamten Hydrobiologie und Hydrographie 43:124-197, 225-280.

Hustedt, F. (1966). Die Kieselalgen Deutschlands, Österreichs und der Schweiz unter Berücksichtigung der übrigen Länder Europas sowie der angrenzenden Meeresgebiete. 3.Teil. Reprint 1977 by Otto Koeltz Science Publishers, Koenigstein, Germany. 816 pp.

Lange-Bertalot, H. (1993). 85 Neue taxa und uber 100 weitere neu definierte Taxa erganzend zur Subwasserflora von Mittleuropa. Bibliotheca Diatomologica 27, 454 p. Cramer, Berlin, Stuttgart.

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)

Transfer INA
Original INA

California Academy of Sciences (CAS)

Nupela tenuicephala CAS

North American Diatom Ecological Database (NADED)

NADED ID: 92027

Autecology Discussion

The specimens pictured on this web page are from a pond in the Mexican Cut Nature Preserve in the Rocky Mountains of Colorado. Nupela tenuicephala has also been recorded from ponds and small lakes in the mountains of Montana, Oregon and Washington. In two of these waters, pH measured 5.88 and 6.30 and electrical conductance measured 3 and 7 µS/cm.


Lower Snowy Lake, North Cascades, Skagit County, Washington: home of Nupela tenuicephala

Credit/Source: Craig Weiland, Adventurers and Scientists for Conservation