Aulacoseira alpigena

(Grunow) Krammer 1991      Category: Centric
BASIONYM: Melosira distans var. alpigena Grunow in Van Heurck 1882

REPORTED AS: Aulacoseira distans var. septentrionalis (Camburn & Charles 2000) 

Asterionella ralfsii var. americana


Aulacoseira ambigua

LM scalebar = 10 µm = 80 pixels.


Contributor: Marina Potapova - May 2009
Diameter: 4-15 µm
Mantle Height: 4-7 µm
Rows of areolae in 10 µm: 15-22


Frustules are cylindrical and 4-15 µm in diameter, with a mantle height of 4-7 µm. The ratio of the mantle height to valve diameter is less than 1. The mantle has convex sides and the valve face is flat. Rows of pervalvar areolae are curved to the right (dextrorse) and number 15-22 in 10 µm. The valve face is unornamented except for one row of marginal areolae. Spines are located at the end of each pervalvar costa. Spines are thin and have an ‘anchor’ shape at the end. The ringleiste is small.

Some valves of A. alpigena have almost straight rows of mantle areolae that also may be almost parallel to the pervalvar axis. Such specimens have been often misidentified as A. distans (Ehrenberg) Simonsen. Crawford and Likhoshway (1999) examined the type material of A. distans and showed that it is characterized by numerous rimportulae that internally form short tubes, situated close to a very deep ringleiste. These rimportulae are easily observed in LM in valve views. A. alpigena does not have such prominent and numerous rimoportulae and differs from A. distans also by having higher density of mantle areolae, shallow ringleiste, and plain valve face.

Original Description

Basionym: Melosira distans var. alpigena
Author: Grunow in Van Heurck 1882
Diameter: µm
Rows of areolae in 10 µm:

Original Description

Original Images

Cite This Page:
Potapova, M. (2009). Aulacoseira alpigena. In Diatoms of the United States. Retrieved April 21, 2018, from

Species: Aulacoseira alpigena

Contributor: Marina Potapova

Reviewer: Sarah Spaulding


Krammer, K. (1991). Morphology and taxonomy of some taxa in the genus Aulacoseira Thwaites (Bacillariophyceae). I. Aulacoseira distans and similar taxa. Nova Hedwigia 52(1-2):89-112.

Links & ID's

Index Nominum Algarum (INA)

Transfer INA
Original INA

California Academy of Sciences (CAS)

Aulacoseira alpigena CAS

NCBI Genbank Taxonomy

Aulacoseira alpigena NCBI
Aulacoseira distans var. alpigena NCBI

North American Diatom Ecological Database (NADED)

NADED ID: 10028

Autecology Discussion

Oligotraphentic species

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

Aulacoseira alpigena

EMAP Response Plots

Aulacoseira alpigena

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.