Frustulia esandalliae

L.L.Bahls 2014      Category: Symmetrical biraphid

Frustulia creuzburgensis


Frustulia inculta

LM scalebar = 10 µm = 40 pixels.


Contributor: Loren Bahls - February 2016
Length Range: 67-113 µm
Width Range: 13.7-18.5 µm
Striae in 10 µm: 25-27


Valves are linear-lanceolate with capitate apices. The axial area is moderately wide. Raphe branches and adjacent longitudinal ribs are slightly curved. Proximal and distal ends of the longitudinal ribs are indistinct. The central area is linear-elliptic and 3.0-5.1 µm wide. A single row of areolae borders the outside of each longitudinal rib. These two rows of areolae continue through the central area where they enclose a smaller space of the same linear-elliptic shape. The two rows of areolae meet at each apex, where they enclose a rounded terminal area that lacks a prominent porte-crayon. Transapical striae are parallel to weakly radiate, becoming weakly convergent near the apices. Reduced striae radiate around the apices. Areolae number 24-26 in 10 μm.

Original Description

Author: L.L.Bahls 2014
Length Range: 67.2-113.0 µm
Width Range: 13.7-18.5 µm
Striae in 10 µm: 25-26

Original Description

Valves are linear-lanceolate with broadly capitate to subcapitate apices. Valve length 67.2-113.0 μm; valve width 13.7-18.5 μm. Axial area is moderately wide and occupied by a robust raphe sternum, the branches of which are nearly straight to slightly bowed in smaller specimens. Centraltwo rows of areolae forming an apically elongate ellipse between the proximal raphe ends. Terminal nodules are spatulate and lack a “porte-crayon”. Proximal and terminal raphe fissures indistinct. Transapical striae parallel to weakly radiate, becoming weakly convergent near the apices, 25-26 in 10 μm. Areolae in the striae 24-26 in 10 μm. SEM.—With additional magnification, external SEM images (Figs. 76, 77) show that the terminal and proximal raphe ends are T-shaped.

Original Images

Cite This Page:
Bahls, L. (2016). Frustulia esandalliae. In Diatoms of the United States. Retrieved April 21, 2018, from

Species: Frustulia esandalliae

Contributor: Loren Bahls

Reviewer: Pat Kociolek


Bahls, L. (2014). New diatoms from the American West–A tribute to citizen science. Proceedings of the Academy of Natural Sciences of Philadelphia 163: 61-84.

Lange-Bertalot, H. (2001). Navicula sensu stricto, 10 genera separated from Navicula sensu lato, Frustulia. Diatoms of Europe 2: 1-526.

Lange-Bertalot, H., Cavacini, P., Tagliaventi, N. and Alfinito, S. (2003). Diatoms of Sardinia: Rare and 76 new species in rock pools and other ephemeral waters. Iconographia Diatomologica 12, 438 pp.

Links & ID's

Index Nominum Algarum (INA)

Original INA

California Academy of Sciences (CAS)

North American Diatom Ecological Database (NADED)


Autecology Discussion

Frustulia esandalliae is known only from a ponded spring (livestock reservoir) in the high desert of eastern Oregon (photos below). The water in this pond is presumably calcareous with a moderately high electrolyte content. The morphologically similar Frustulia alfinitosilviae from Sardinia occupies a similar habitat: bottom sediments of ponds that dry out during summer and have a high electrolyte content.


Dick’s Spring, Lake County, Oregon.

Credit/Source: Sage Clegg, Adventurers and Scientists for Conservation

Dick’s Spring Cow Pond, Lake County, Oregon. The sample containing Frustulia esandalliae was a composite of materials collected from the spring and the pond.

Credit/Source: Sage Clegg, Adventurers and Scientists for Conservation