Encyonopsis microcephala
(Grunow) Krammer 1997 Category: Asymmetrical biraphid
BASIONYM: Cymbella microcephala Grunow
LM scalebar = 10 µm = 80 pixels.
Observations
Contributor: Pat Kociolek - March 2011
Length Range: 10-16 µm
Width Range: 3-4 µm
Striae in 10 µm: 22-24
Description
Valves are asymmetrical to the apical axis, the dorsal margin is distinctly convex, then ventral margin is slightly convex. The apices are protracted and relatively large compared to the size of the valve, broadly rounded, and curved slightly towards the dorsal margin. The axial area is narrow. The central area is indistinct, when present it is formed by a short stria on the ventral margin. The raphe is filiform and slightly arched towards the dorsal margin. Striae are parallel on the dorsal margin, radiate on the ventral margin.
Original Description
Basionym: Cymbella microcephala
Author: Grunow
Length Range: µm
Striae in 10 µm:
Original Description
C. microcephala Grun. (Atl. Ρ1. VΙΙΙ fig. 36-39 — in Type Νο 211.) Valves assez étroitement lanceolées, à peine cymbiformes, à extrémités fortement rostrées-capitées ; raphé faiblement arqué ; stries délicates, 24 dans les grandes formes, 28 à 30 dans les petites formes. Longueur : 1 1/2 à 2 1/3 c.d.m.
Original Images
Cite This Page:
Kociolek, P. (2011). Encyonopsis microcephala. In Diatoms of the United States. Retrieved May 18, 2013, from http://westerndiatoms.colorado.edu/taxa/species/encyonopsis_microcephala
Species: Encyonopsis microcephala
Contributor: Pat Kociolek
Image Credit: Pat Kociolek
- Valves asymmetrical to the apical axis
- Apices protracted
- Striae parallel on the dorsal margin
- Striae radiate on the ventral margin
Valves are asymmetrical to the apical axis. The apices are protracted and relatively large compared to the size of the valve, broadly rounded, and curved slightly towards the dorsal margin. The axial area narrow. Striae are parallel on the dorsal margin, radiate on the ventral margin and number 22-24 in 10 µm.
Compare
This species is distinguished from E. subminuta on the basis of the shape of the valve, the structure of the striae and the relative size of the apices.
Encyonopsis subminuta
Citations
Krammer, K. (1997). Die cymbelloiden Diatomeen. Eine Monographie der weltweit bekannten Taxa. Teil 2. Encyonema part., Encyonopsis and Cymbellopsis. Bibliotheca Diatomologica 37:1-469.
Links & ID's
Index Nominum Algarum (INA)
California Academy of Sciences (CAS)
North American Diatom Ecological Database (NADED)
NADED ID: 203002
Autecology Discussion
EMAP Assessment
Sampling for 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). Streams and rivers in 12 western states (Arizona, California, Colorado, Idaho, Montana, Nevada, North Dakota, Oregon, South Dakota, Utah, Washington and Wyoming). Over 1200 sites on 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
Encyonopsis microcephala
Distribution
The distribution map represents the relative abundance of this Encyonopsis microcephala in the western EMAP study. Relative abundance is a measure of the proportion of cells of this species based on a "fixed count" of 300 total diatom cells counted and identified. Each of the western EMAP sample sites is shown, either with a black dot for sites where Encyonopsis microcephala was not recorded, or with a red circle indicating the relative abundance of Encyonopsis microcephala.
Note that the size of the proportional symbols varies between species to help show both abundant and rare species.
Scale for the map to the left
EMAP Response Plots
Encyonopsis microcephala
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.