Frustulia bahlsii

Edlund and Brant 1997      Category: Symmetrical biraphid

Frustulia asiatica


Frustulia capitata

LM scalebar = 10 µm = 20 pixels.


Contributor: David R.L. Burge | Mark Edlund | Lynn Brant - May 2015
Length Range: 123-195 µm
Width Range: 26-31 µm
Striae in 10 µm: longitudinal striae 19-22, transverse striae 24-25


Valves area lanceolate to weakly rhombic, with rounded apices. Longitudinal ribs are straight, except at the central nodule, where they are constricted. The distal end of the longitudinal ribs is spatulate and blunt. The raphe is straight and filiform. Both the proximal and distal raphe ends are T-shaped. Transverse striae are parallel, except at the apices where they are circumradiate. Longitudinal striae are wavy throughout.

Original Description

Author: Edlund and Brant 1997
Length Range: 98-193 µm
Width Range: 24-33 µm
Striae in 10 µm: longitudinal striae 16-23, transverse striae 20-26

Original Description

Cells solitary. Valves lanceolate to rhombic-lanceolate, valve face flat, apices rounded to slightly rostrate (Figs 1-6). Valve length 98-193 µm, valve breadth 24-33 µm. Central area not differentiated from narrow axil area on valve exterior (Figs 5, 7). Axial area terminates in a slightly expanded spatulate hyaline field (Figs 1-4, 9). Striae punctate; longitudinal striae parallel to slightly undulate, 16-23 in 10 µm and transverse striae parallel to slightly undulate, 20-26 in 10 µm (Figs 1-4, 11-14). Striae continuous around valve apices (Figs 9, 10). Areolae poroid, occluded internally by domed vela (Figs 7-10). Raphe straight and simple; its proximal and distal ends T-shaped on the valve exterior (Figs 7, 9). Raphe enclosed between two internally thickened siliceous ribs (Figs 6, 8, 10). Ribs parallel to slightly curved internally along axial area, slightly expanded around proximal raphe ends to form spatulate thickening rather than a “porte-crayon” usually present in the genus (Fig. 10).

Original Images

Cite This Page:
Burge, D., Edlund, M., and Brant, L. (2015). Frustulia bahlsii. In Diatoms of the United States. Retrieved April 21, 2018, from

Species: Frustulia bahlsii

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

Reviewer: Sarah Spaulding


Edlund, M.B. and Brant, L. (1997). Frustulia bahlsii sp. nov., a freshwater diatom from the Eastern U.S.A. Diatom Research 12 (2): 207-216. 10.1080/0269249X.1997.9705415

Links & ID's

Index Nominum Algarum (INA)

Original INA

California Academy of Sciences (CAS)

Frustulia bahlsii CAS

NCBI Genbank Taxonomy

Frustulia bahlsii NCBI

North American Diatom Ecological Database (NADED)

NADED ID: 35040

Autecology Discussion

Frustulia bahlsii has been reported from Maine, New Hampshire, New Jersey, and North Carolina (Edlund and Brant 1997). The type locality, Flat Laurel Gap Bog, Haywood County, North Carolina, is a sphagnum bog with low pH and low conductivity. We have also observed F. bahlsii in the Upper Peninsula of Michigan and southern Alaska.