Aulacoseira subarctica

(O.Müll.) E.Y.Haw. 1990      Category: Centric
BASIONYM: Melosira italica subsp. subarctica O.Müll. 1906
SYNONYM(S): Aulacoseira  italica subsp. subarctica (O.Müll.) Simonsen 

Aulacoseira pusilla


Aulacoseira tenella

LM scalebar = 10 µm = 80 pixels.


Contributor: Marina Potapova | Jonathan English - December 2010
Diameter: 3-14 µm
Mantle Height: 2.5-14 µm
Rows of areolae in 10 µm: 15-22


Cells are cylindrical and form long chains. Valves are 3-14 µm in diameter, with a mantle height of 2.5-14 µm. Most cells are narrow, 3-6 µm in diameter, with the ratio of the mantle height to valve diameter greater than 1. Wider cells have the the ratio of the mantle height to valve diameter between 0.3 and 1. The mantle has straight sides and the valve face is flat. Rows of pervalvar areolae are curved to the right (dextrorse). There are 15-22 rows of areolae in 10 µm. The collum is approximately ¼-1/10 of the mantle height. The valve face is plain with or without a peripheral ring of areolae and sometimes has additional rings of small areolae. The spines are robust, pointed and originate from two or, more rarely, from three pervalvar costae. Unlike most other Aulacoseira species, A. subarctica does not have differentiated linking and separation valves; all valves have the spines of the same type. The ringleiste is solid, shelf-like. A few rimoportulae can be visible near ringleiste and near valve face.

Original Description

Basionym: Melosira italica subsp. subarctica
Author: O.Müll. 1906
Diameter: 3-15 µm
Mantle Height: 2.5-18 µm
Rows of areolae in 10 µm: 18

Original Description

Theca zylindrisch, Pleuraseite rechteckig mit geraden oder wenig gekrümmten Enden und abgerundeten Ecken. Disci kreisformig, geradflächig oder mehr oder weniger gekrümmt, die be¬nachbarten eng verbunden, an den Rändern auseinanderweichend, einen Pseudosulcus bildend. In den schmäleren Fäden zwischen je zwei Discen zuweilen ein freier Raum. Discusfläche mit feinen Poren bedeckt, die Ränder mit starken, submarginal inserierten Zähnen besetzt, die mit den gegenüberstehenden der benachbarten Discusränder alternieren. — Porenreihen auf der Mantelfläche gegen die Pervalvarachse geneigt, in Spirallinien vom Halsteil zur Discusfläche aufsteigend und mit den Linien der benachbarten Zellhälfte ein S bildend, in Abständen von ca. 18 auf 10 μ. Poren punktförmig, kräftig, ca. 18 auf 10 μ in den Spiralreihen, in der Querrichtung leicht wellenförmig verlaufend. Zellwand stark, innere Mantellinie gerade. Sulcus eine den kurzen Hals abschnürende tiefere Ringfurche. Höhe 2,5—18 μ; Durchmesser 3 —15 μ. Verhältnis des Durchmessers zur Höhe 1 : 0,2—6,0. Forma recta. Taf. II, Fig. 9. Fäden bis 20 Zellen beobachtet Höhe 10,5—18; Durch¬messer 3—5 μ, Forma curvata vel spiralis. Fäden mehr oder weniger gekrümmt, kreisförmig oder spiralig gewunden, bis zu 4 übereinander liegenden Spiralen von 58 Zellen. Durchmesser der Spiralen 84—127 μ, Kreisschluβ bei mindestens 12 Zellen. Höhe 8,5—12 μ. Durchmesser 4—10,5 μ.

Original Images

Cite This Page:
Potapova, M., and English, J. (2010). Aulacoseira subarctica. In Diatoms of the United States. Retrieved April 22, 2018, from

Species: Aulacoseira subarctica

Contributor: Marina Potapova | Jonathan English

Reviewer: Mark Edlund


Gibson, C.E., Anderson, N.J., and Haworth, E.Y. (2003). Aulacoseira subarctica: taxonomy, physiology, ecology and palaeoecology. . European Journal Phycology 38: 83-101.

Haworth, E.Y. (1988). Distribution of diatom taxa of the old genus Melosira (now mainly Aulacoseira) in Cumbrian waters. In: Round, F.E. (ed.), 1988, Algae and the aquatic environment. Contributions in honour of J.W.G. Lund. Biopress Ltd., Bristol, pp. 138-167.

Haworth, E.Y. (1990). Diatom name validation. Diatom Research 5(1):195-196. 10.1080/0269249X.1990.9705104

Jewson, D.H. (1992). Size reduction, reproductive strategy and the life cycle of a centric diatom. Phil. Trans. R. Soc., Lond. B 336:191-213.

Lepskaya E.V., Jewson D.H. and Usoltseva M.V. (2010). Aulacoseira subarctica in Kurilskoye Lake, Kamchatka a deep, oliogotrophic lake and important salmon nursery
Diatom Research 25: 323-335. 10.1080/0269249X.2010.9705853

Müller, O. (1906). Pleomorphismus Auxosporen und Dauersporen bei Melosira-Arten. Jahrbücher für wissenschaftliche Botanik 43(1):49-88.

Simonsen, R. (1979). The diatom system: ideas on phylogeny. Bacillaria 2: 9-71.

Siver, P.A. and Kling, H. (1997). Morphological observations of Aulacoseira using scanning electron microscopy. Can. J. Bot. 75: 1807–1835.

Tuji, A. and Houki, A. (2004). Taxonomy, ultrastructure, and biogeography of the Aulacoseira subarctica species complex. Bulletin of the National Science Museum, Series B (Botany), Tokyo 30(2):35-55.

Links & ID's

Index Nominum Algarum (INA)

Transfer INA

California Academy of Sciences (CAS)

Aulacoseira subarctica CAS

NCBI Genbank Taxonomy

Aulacoseira subarctica NCBI

North American Diatom Ecological Database (NADED)

NADED ID: 10015

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

Aulacoseira subarctica

EMAP Response Plots

Aulacoseira subarctica

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.