(Ehrenberg) D.M. Williams 1985 Category: Araphid
BASIONYM: Fragilaria anceps Ehrenberg 1843
SYNONYM(S): Diatoma anceps (Ehrenberg) Kirchner 1878
Contributor: Ian Bishop - May 2015
Length Range: 10-46 µm
Width Range: 5.2-7.0 µm
Striae in 10 µm: 18-23
Valves apically and transapically symmetrical; linear with capitate ends. Small valves may be more elliptical with less capitate ends than larger valves. Valves possess both primary and secondary costae, which measure 3.3-4.9 in 10 µm. Striae are visible in LM but individual areolae cannot be observed. The sternum is central and well-defined. Each valve has a single, sub-apical rimoportula.
Basionym: Fragilaria anceps
Author: Ehrenberg 1843
Length Range: µm
Striae in 10 µm:
F? anceps, parva linearis testulis a latere laxe striatis, apicibus, constrictis obtusis subcapitatis. Gomphonema Pupulae affinis.
Ehrenberg, C.G. (1843). Verbreitung und Einfluß des mikroskopischen Lebens in Süd- und Nord-Amerika. Abhandlungen der Königlichen Akademie der Wissenschaften zu Berlin, 1841: 291-445, 4 Tafel.
Williams, D.M. (1985). Morphology, taxonomy and inter-relationships of the ribbed araphid diatoms from the genera Diatoma and Meridion (Diatomaceae: Bacillariophyta). Bibliotheca Diatomologica 8: 1-228.
Williams, D.M. (1990). Cladistic analysis of some freshwater araphid diatoms (Bacillariophyta) with particular reference to Diatoma and Meridion. Plant Systematics and Evolution 171: 89-97.
Meridion anceps is widely distributed across North America, notably in the western United States. It can be found in aerophilic zones, wet walls, small creeks, larger rivers. It is common in submerged mosses and liverworts and co-occurs with several species in the Meridion, Diatoma, Tabellaria, and Tetracylus genera.
Distribution of D anceps in the continental U.S. rivers sampled for the National Water Quality Assessment program. (Retrieved 08 May 2015)
Credit/Source: USGS BioData
Distribution of D anceps in the Alaskan rivers sampled for the National Water Quality Assessment program. (Retrieved 08 May 2015)
Credit/Source: USGS BioData
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.
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.