Achnanthidium kranzii

(Lange-Bert.) Round and Bukht. 1996      Category: Monoraphid
BASIONYM: Achnanthes kranzii Lange-Bert. in Lange-Bert. and Krammer 1989

Achnanthidium gracillimum


Achnanthidium kriegeri

LM scalebar = 10 µm = 80 pixels.


Contributor: Marina Potapova - March 2011
Length Range: 8-20 µm
Width Range: 2.8-3.8 µm
Striae in 10 µm: 24-30 in the center valve, up to 40 at the ends


Frustules are monoraphid with a concave raphe valve and a convex rapheless valve. Valves are linear-lanceolate to linear-elliptical with slightly drawn-out ends. The raphe valve has a large rectangular central area that often extends to valve margins. The rapheless valve has an apically elongated elliptical or rhomboid central area. Proximal external raphe endings are simple. Terminal raphe fissures are short and sharply curved to the same side. Striae are moderately radiate in the center of both valves, becoming parallel at the apices, 24-30 in 10 µm in the central valve, up to 40 in 10 µm at the apices. Striae are uniseriate. One row of areolae is present on the valve mantle, visible in SEM. External areolae openings of areolae are very small and vary in shape from circular to transapically elongated.

Original Description

Basionym: Achnanthes kranzii
Author: Lange-Bert. in Lange-Bert. and Krammer 1989
Length Range: 6-20 µm
Width Range: 3.5-4 µm
Striae in 10 µm: 25-30 in the center valve, 35-40 at the ends

Original Description

Valvae ellipticae, lineari-ellipticae ad elliptico-lanceolatae apicibus obtuse vel late rotundatis, 6-20 µm longae, 3.5-4 µm latae. Raphovalva: Rami raphis filiformes, recto ex poris centralibus modice approximatis, ad apicibus versus, prope marginem limbi curvati in eandem directionem. Area axialis anguste linearis ad lineari-lanceolata. Area centralis plus minusque amplam fasciam formans pro parte margines attingens. Areovalva: areae centralis rhombice transirens in aream axialis anguste linearis. Striae transapicales modice radiantes in medio at amplior positae, circiter 25-30/10 µm, sub apices parallelae vel paulo convergentes et densior positae, circiter 35-40/10 µm. A speciebus similibus satis differt combinatione pljurium qualitatium.

Original Images

Cite This Page:
Potapova, M. (2011). Achnanthidium kranzii . In Diatoms of the United States. Retrieved April 26, 2018, from

Species: Achnanthidium kranzii

Contributor: Marina Potapova

Reviewer: Sarah Spaulding


Lange-Bertalot, H. and Krammer, K. (1989). Achnanthes eine Monographie der Gattung mit Definition der Gattung Cocconeis and Nachtragen zu den Naviculaceae. Bibliotheca Diatomologica 18, 393 pp. Cramer, Berlin, Stuttgart.

Round, F. E. and Bukhtiyarova, L. (1996). Four new genera based on Achnanthes (Achnanthidium) together with a re-definition of Achnanthidium. Diatom Research 11: 345-361.

Links & ID's

Index Nominum Algarum (INA)

Original INA

California Academy of Sciences (CAS)

Achnanthidium kranzii CAS

NCBI Genbank Taxonomy

Achnanthidium kranzii NCBI

North American Diatom Ecological Database (NADED)

NADED ID: 1027

Autecology Discussion

EMAP Assessment

The Environmental Protection Agency (EPA) western Environmental Monitoring and Assessment Program (EMAP) study was completed during the years 2000-2004 (see citations at bottom of this page). Over 1200 streams and rivers in 12 western states (Arizona, California, Colorado, Idaho, Montana, Nevada, North Dakota, Oregon, South Dakota, Utah, Washington and Wyoming) were selected for sampling based on a stratified randomized design. This type of design insures that ecological resources are sampled in proportion to their actual geographical presence. Stratified randomized design also allows for estimates of stream length with a known confidence in several “condition classes” (good or least-disturbed, intermediately-disturbed, and poor or most-disturbed) for biotic condition, chemistry and habitat.

EMAP Distribution

Achnanthidium kranzii

EMAP Response Plots

Achnanthidium kranzii

EMAP citations

Results are published in:

Johnson, T., Hermann, K., Spaulding, S., Beyea, B., Theel, C., Sada, R., Bollman, W., Bowman, J., Larsen, A., Vining, K., Ostermiller, J., Petersen, D. Hargett, E. and Zumberge, J. (2009). An ecological assessment of USEPA Region 8 streams and rivers. U.S. Environmental Protection Agency Region 8 Report, 178 p.

Stoddard, J. L., Peck, D. V., Olsen, A. R., Larsen, D. P., Van Sickle, J., Hawkins, C. P., Hughes, R. M., Whittier, T. R., Lomnicky, G. A., Herlihy, A. T., Kaufman, P. R., Peterson, S. A., Ringold, P. L., Paulsen, S. G., and Blair, R. (2005). Environmental Monitoring and Assessment Program (EMAP) western streams and rivers statistical summary. U.S. Environmental Protection Agency Report 620/R-05/006, 1,762 p.

Stoddard, J. L., Peck, D. V., Paulsen, S. G., Van Sickle, J., Hawkins, C. P., Herlihy, A. T., Hughes, R. M., Kaufman, P. R., Larsen, D. P., Lomnicky, G. A., Olsen, A. R., Peterson, S. A., Ringold, P. L., and Whittier, T. R. (2005). An ecological assessment of western streams and rivers. U.S. Environmental Protection Agency Report 620/R-05/005, 49 p.