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Cavinula pseudoscutiformis

(Hust.) D.G.Mann and Stickle in Round, R.M.Crawford and D.G.Mann 1990      Category: Symmetrical biraphid
BASIONYM: Navicula pseudoscutiformis Hust. in Pascher 1930

Cavinula maculata


Cavinula pusio

LM scalebar = 10 µm = 80 pixels.


Contributor: Megan Otu | Sarah Spaulding - March 2011
Length Range: 6-10 µm
Width Range: 4.9-9.3 µm
Striae in 10 µm: 16-24 in the center valve


Valves are nearly round. Areolae are approximately 36 in 10 μm. The axial area is narrow and linear and extends onto the valve margins at the apices; the central area is small and nearly indistinguishable from the axial area. The raphe is filiform with slightly expanded central raphe ends. The striae are punctate and strongly radiate. Striae are incomplete in the central valve, that is, several are short and do not extend from the central area to the valve margin. The stria density increases towards the apices. The external openings of the areolae are round. Internally, the areolae are elongated. Internally, the raphe slit is narrow at proximal and terminal ends. The helictoglossae are reduced.

Original Description

Basionym: Navicula pseudoscutiformis
Author: Hust. in Pascher 1930
Length Range: 9-15 µm
Width Range: 7-13 µm
Striae in 10 µm: 24

Original Description

Schalen breit-elliptisch, fast kreisförmig, mit breit gerundeten Polen, 9-15 µ lang, 7-13 breit. Axialarea eng, um den Mittelknoten wenig erweitert. Zentralporen der Raphe entfernt gestellt. Transapikalstreifen durchweg radial, zart, etwa 24 in 10 µ, in der Mitte von ungleicher Länge, zart punktiert.

Original Images

Cite This Page:
Otu, M., and Spaulding, S. (2011). Cavinula pseudoscutiformis. In Diatoms of the United States. Retrieved May 23, 2018, from

Species: Cavinula pseudoscutiformis

Contributor: Megan Otu | Sarah Spaulding

Reviewer: Sarah Spaulding


Hustedt, F. (1930). Bacillariophyta (Diatomeae). In: Die Subwasser Flora Mitteleuropas. (A. Pascher, ed.),10, Gustav Fischer, Jena. 468 pp.

Round, F.E., Crawford, R.M. and Mann, D.G. (1990). The Diatoms. Biology and Morphology of the Genera. Cambridge University Press, Cambridge, 747 pp.

Links & ID's

Index Nominum Algarum (INA)

Original INA
Transfer INA

California Academy of Sciences (CAS)

Cavinula pseudoscutiformis CAS

North American Diatom Ecological Database (NADED)

NADED ID: 195003

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

Cavinula pseudoscutiformis

EMAP Response Plots

Cavinula pseudoscutiformis

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.