Visit us at

Diatoms of the United States is now known as Diatoms of North America.
This site has been redesigned and updated, and will be closing soon.

Sellaphora auldreekie

D.G.Mann and S.M.McDonald 2004      Category: Symmetrical biraphid

Sellaphora atomoides


Sellaphora bacilloides

LM scalebar = 10 µm = 80 pixels.


Contributor: David R.L. Burge | Mark Edlund - June 2017
Length Range: 27-32 µm
Width Range: 7.0-7.5 µm
Striae in 10 µm: 19-21


Valves are elliptic-lanceolate, with protracted, rostrate apices. The valve ends are broadly rounded, with prominent polar bars that are recurved into the valve. The axial area and conopeum are linear and narrow. The raphe is filiform and straight. The proximal raphe ends are inflated, while the distal raphe ends are unilaterally deflected. The central area is strongly bow-tie shaped, and bordered by short striae of even length. The central area may be asymmetric, with one side of the “bow-tie” larger than the other. Striae are strongly radiate, becoming convergent at the apices.

This taxon is considered a member of the S. pupula species complex. Prior to the description of S. auldreekie in 2004, it would have been identified as S. pupula. Likely, many of the records in surveys of North America this taxon is recorded as S. pupula.

Original Description

Author: D.G.Mann and S.M.McDonald 2004
Length Range: 15-35 µm
Width Range: 6.6-8 µm
Striae in 10 µm: 19-24

Original Description

Valvae ellipticae polis valde rostratis angustis, in medio quam in polis 2-3plo latiores, 15-35 µm longae, 6.6-8 µm latae. Area ax­ialis angusta recta; raphosternum extus non vixve elevatum, fronte igitur plana. Area centralis est subfascia angulis acutis dictu Angliae ‘bow-tie’ similis. Areolae poroides parvae circulares secus striam c.65 in 10 µm regulatim dispositae. Striae uniseriatae 19-24 in 10 µm pro parte maxima radiantes, in valvis maioribus prope polos convergentibus. Transtra polaria ad axem apicalem perpendicularia. Raphe simplex recta filiformis, extremis centralibus expansis versus latus secundarium fexis.

Original Images

Cite This Page:
Burge, D., and Edlund, M. (2017). Sellaphora auldreekie. In Diatoms of the United States. Retrieved May 25, 2018, from

Species: Sellaphora auldreekie

Contributor: David R.L. Burge | Mark Edlund

Reviewer: Marina Potapova


Mann, D.G., McDonald, S.M., Bayer, M.M., Droop, S.J.M., Chepurnov, V.A., Loke, R.E., Ciobanu, A. and du Buf, J.M.H. (2004). The Sellaphora pupula species complex (Bacillariophyceae): morphometric analysis, ultrastructure and mating data provide evidence for five new species. Phycologia 43: 459-482.

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)

Original INA

California Academy of Sciences (CAS)

Sellaphora auldreekie CAS

North American Diatom Ecological Database (NADED)


Autecology Discussion

Due to morphological similarities with Sellpahora pupula, S. auldreekie has not been illustrated from the United States. Here we observed samples from Moody Lake, Minnesota.