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Diatoms of the United States is now known as Diatoms of North America.
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Eunotia tauntoniensis

Hust. 1926      Category: Eunotioid

Eunotia superbidens


Eunotia tenella

LM scalebar = 10 µm = 20 pixels.


Contributor: David R.L. Burge | Lynn Brant | Mark Edlund - June 2016
Length Range: 97-338 µm
Width Range: 6.4-8.9 µm
Striae in 10 µm: 12-14 in the valve center, 14-16 at the ends


Valves and narrow and arcuate with a convex dorsal margin and a concave ventral margin. Apices are distinctly expanded, terminating with apiculate ends. A single rimoportula is often present on the dorsal side of the apex. A helictoglossa is present on the ventral side of the valve face, next to the valve apex. The raphe curves onto the ventral margin toward the valve center. Striae are perpendicular to the valve margin (occurring 12-14 in 10 µm) at the valve center, becoming more dense (14-16 in 10 µm) near the apices. In some specimens, the striae bifurcate at the ventral margin. Areolae are fine, occurring about 40 in 10 µm.

As Patrick (1945) pointed out, Hustedt (1913) invalidly described E. tauntoniensis by providing only a name and a figure. In 1926, however, Hustedt validated E. tauntoniensis by providing a diagnosis of the raphe as a distinguishing feature from other similar taxa. Therefore, Patrick (1945) is superfluous to Hustedt’s earlier nomenclatural validation.

Original Description

Author: Hust. 1926
Length Range: µm
Striae in 10 µm:

Original Description

Original Images

Cite This Page:
Burge, D., Brant, L., and Edlund, M. (2016). Eunotia tauntoniensis. In Diatoms of the United States. Retrieved May 20, 2018, from

Species: Eunotia tauntoniensis

Contributor: David R.L. Burge | Lynn Brant | Mark Edlund

Reviewer: Jen Beals


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.

Edlund, M.B. and Brant, L.A. (2010). Eunotia charliereimeri, a new Eunotia species (Bacillariophyceae) with amphoroid frustule symmetry. Proceedings of the Academy of Natural Sciences of Philadelphia 160(1):47-56. 10.1635/053.160.0106

Gaiser, E.E. and Johansen, J. (2000). Freshwater diatoms from Carolina bays and other isolated wetlands on the Atlantic Coastal Plain of South Carolina, USA, with descriptions of seven taxa new to science. Diatom Research 15(1): 75-130. 10.1080/0269249X.2000.9705487

Hustedt, F. (1926). Untersuchungen über den Bau der Diatomeen. I. Raphe und Gallertporen der Eunotioideae. Berichte der Deutschen Botanishen Gesellschaft 44 (2): 142-150. 10.1111/j.1438-8677.1926.tb00950.x

Patrick, R.M. (1945). A taxonomic and ecological study of some diatoms from the Pocono Plateau and adjacent regions. Farlowia 2(2):143-221.

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.

Siver, P.A. and Hamilton, P.B. (2011). Diatoms of North America: The Freshwater Flora of Waterbodies on the Atlantic Coastal Plain. Iconographia Diatomologica 22.

Links & ID's

Index Nominum Algarum (INA)

Original INA

California Academy of Sciences (CAS)

North American Diatom Ecological Database (NADED)

NADED ID: 33126

Autecology Discussion

Here we observed E. tauntoniensis forming semi-stellate colonies in Bear Meadows Bog, a low pH (4.3-4.8) and low conductivity (19 to 38 µS) wetland in Appalachian Pennsylvania (Edlund and Brant 2010). Eunotia tauntoniensis has been reported from low pH lakes and wetlands of New England and the Atlantic Coastal Plain (Patrick and Reimer 1966, Camburn and Charles 2000, Gaiser and Johansen 2000, Siver and Hamilton 2011), as well as being observed here from wetlands in valleys of the Appalachian Mountains.


Bear Meadows Bog, where E. tauntoniensis was sampled.

Credit/Source: Lynn Brant

Colony of E. tauntoniensis. Scale bar = 10 µm

Credit/Source: Mark Edlund

Distribution of Eunotia tauntoniensis in rivers of the continental U.S. based on the National Water Quality Assessment program. Retrieved 26 July 2016.

Credit/Source: USGS BioData


May 18, 2017 - Size range expansion and image update

Updated the observed size range maximum from 255 to 337 microns and added an image of this specimen.