Eunotia gibbosa

Grunow in Van Heurck 1881      Category: Eunotioid

REPORTED AS: Eunotia gibbosa (Lange-Bertalot et al. 2011, p. 110, figs. 230: 24-26) | Eunotia gibbosa (Patrick and Reimer 1966, p. 216, plate 14, fig. 1) | Eunotia didyma var. inflata (Hustedt in A. Schmidt et al. 1913, figs. 289: 1, 2; Simonsen 1987, p. 39, plate 39, figs. 1-5) 

Eunotia formica


Eunotia hexaglyphis

LM scalebar = 10 µm = 80 pixels.


Contributor: Loren Bahls - January 2014
Length Range: 27-38 µm
Width Range: 10.2-13.6 µm
Striae in 10 µm: 9-12 at the valve center, more near the apices


Valves are bilobed and nearly symmetric with respect to the apical axis. The two lobes are separated by a narrow, central isthmus. The dorsal lobes are slightly more closely placed and than the ventral lobes. Valve width at the widest point of the lobes is 10.2-13.6 µm. Valve width at the isthmus is 5.8-8.4 µm. The apices are bluntly rounded and removed from the lobes. Helictoglossae are relatively distant from the apices on the ventral side. Terminal raphe fissures conform to the ventral contours of the valve and are dorsally deflected. Striae are finely punctate and radiate with respect to the isthmus, although some striae of each lobe may also radiate. Short interstriae may be present along both the dorsal and ventral margins. Areolae are difficult to resolve in LM and number 30-35 in 10 µm.

Original Description

Author: Grunow in Van Heurck 1881
Length Range: µm
Striae in 10 µm:

Original Description

Original Images

Cite This Page:
Bahls, L. (2014). Eunotia gibbosa. In Diatoms of the United States. Retrieved April 24, 2018, from

Species: Eunotia gibbosa

Contributor: Loren Bahls

Reviewer: Paula Furey


Camburn, K.E. and Charles, D.F. (2000). Diatoms of Low-Alkalinity Lakes in the Northeastern United States. Academy of Natural Sciences of Philadelphia, Special Publication 18, 152 pp.

Lange-Bertalot, H., Bak, M., Witkowski, A. and Tagliaventi, N. (2011). Eunotia and some related genera. Diatoms of the European Inland Waters and Comparable Habitats. 6: 747 pp.

Patrick, R.M. and Reimer, C.W. (1966). The Diatoms of the United States exclusive of Alaska and Hawaii, V. 1. Monographs of the Academy of Natural Sciences of Philadelphia 13.

Schmidt, A. (-). (1874-1959). Atlas der Diatomaceen-Kunde, von Adolf Schmidt, continued by Martin Schmidt, Friedrich Fricke, Heinrich Heiden, Otto Muller, Friedrich Hustedt. Reprint 1984, Koeltz Scientific Books, Konigstein, 480 plates.

Simonsen, R. (1987). Atlas and Catalogue of the Diatom Types of Friedrich Hustedt. J. Cramer, Berlin & Stuttgart 1: 525 pp.

Van Heurck, H. (1881). Synopsis des Diatomées de Belgique. Atlas. Ducaju & Cie., Anvers. pls 31-77.

Links & ID's

Index Nominum Algarum (INA)

Original INA

California Academy of Sciences (CAS)

Eunotia gibbosa CAS

North American Diatom Ecological Database (NADED)

NADED ID: 33022

Autecology Discussion

The specimens of Eunotia gibbosa shown here were collected from a lake in the North Cascade Mountains of Washington (photo below) and from Shoofly Meadows in western Montana. Shoofly Meadows is a large, undisturbed complex of marshes, wet meadows, and poor fens in the Rattlesnake Mountains near Missoula. Elsewhere in the United States, E. gibbosa has been recorded from the Adirondack Mountains in New York (Camburn & Charles 2000, Patrick & Reimer 1966), from Bemis Lake, New Hampshire (Lange-Bertalot et al. 2011), and as a fossil from the Kings River, Nevada (Hustedt in Schmidt et al. 1913). This species has not been confirmed outside of North America.


Cutthroat Lake, Okanogan County, Washington: home of Eunotia gibbosa.

Credit/Source: Ryan Davis, Adventurers and Scientists for Conservation.