Karayevia oblongella

(Østrup) Aboal in Aboal, Alvarez-Cobelas, Cambra and Ector 2003      Category: Monoraphid
BASIONYM: Achnanthes oblongella Østrup 1902

Karayevia nitidiformis

 

Karayevia ploenensis var. gessneri
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LM scalebar = 10 µm = 80 pixels.

Observations

Contributor: Marina Potapova -
Length Range: 6-18 µm
Width Range: 3.7-7 µm
Striae in 10 µm: 9-12 on rapheless valve, 24-30 on raphe valve

Description

Valves are elliptical-lanceolate to linear-elliptical. The raphe valve has a narrow linear axial area and a transversely rectangular or bow tie-shaped central area. The raphe is straight, without terminal fissures. The proximal and distal raphe ends are slightly expanded. The proximal raphe ends curve toward opposite sides internally. Striae on raphe valve are slightly radiate in the valve center and strongly radiate and curved at apices, 24-30 in 10 µm. The areolae openings are small, round. The rapheless valve has a lanceolate axial area. The central area is usually not differentiated from the axial area, but sometimes two middle striae on one side of the valve are more distant from each than other striae. Striae on rapheless valve are broader than those on the raphe valve, punctate, parallel in the center and radiate at apices, 9-12 in 10 µm. Shortened marginal striae are often present. The openings of the areolae are apically elongated, internally areolae open into a shallow chamber.

Original Description

Basionym: Achnanthes oblongella
Author: Østrup 1902
Length Range: 57 µm
Width Range: 6 µm
Striae in 10 µm: 10 in "epitheca" (rapheless valve)

Original Description

L. 0,057 mm., B. 0,006 mm. Epitheca: apical area narrow, 10 striae in 0,01 mm., finely transversely lineated. Hypotheca: striæ very fine, slightly curved. Central area narrow. Hypotheca of this small species highly reminds of Navicula Rotœana Grun. var. oblongella Grun. (V. H., Syn. tab. XIV,.fig. 21). But as I have seen both valves in situ, I am quite sure it is an Achnanthes.

Original Images

Cite This Page:
Potapova, M. (). Karayevia oblongella. In Diatoms of the United States. Retrieved May 18, 2013, from http://westerndiatoms.colorado.edu/taxa/species/karayevia_oblongella

Species: Karayevia oblongella

Contributor: Marina Potapova

Reviewer: Rex Lowe

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Image Credit: Marina Potapova

  1. Valves elliptical to linear-elliptical
  2. Striae at least twice denser on raphe valve than on rapheless valve
  3. Raphe valve with transversely rectangular or bow tie-shaped central area
  4. Rapheless valve with lanceolate axial area

Valves are elliptical to linear-elliptical. The raphe valve has a narrow linear axial area and a transversely rectangular or bow tie-shaped central area. Striae on raphe valve are slightly radiate in the valve center and strongly radiate and curved at apices, 24-30 in 10 µm. The rapheless valve has a lanceolate axial area. Striae on rapheless valve are broader than those on the raphe valve, punctate, parallel in the center and radiate at apices, 9-12 in 10 µm.

Compare

Karayevia oblongella can be easily distinguished by its elliptical to linear-elliptical valves and much denser striae on raphe valve compared to rapheless valve.

Citations

Aboal, M., Alvarez-Cobelas, M., Cambra, J. and Ector, L. (2003). Floristic list of non marine diatoms (Bacillariophyceae) of Iberian Peninsula, Balearic Islands, and Canary Islands. Updated taxonomy and bibliography. In: A. Witkowski (ed.), Diatom Monographs. A.R.G. Gantner Verlag K.G., 4: 639 pp.

Østrup, E. (1902). Freshwater Diatoms [in Flora of Koh Chang. Part VII. Contributions to the knowledge of the gulf of Siam.John Schmidt (ed.). Preliminary Rept. Bot., Results Dan. Exped. to Siam (1899-1900)]. Botanisk Tidsskrift 25(1): 28-41.

Links & ID's

Index Nominum Algarum (INA)

Original INA

California Academy of Sciences (CAS)

Karayevia oblongella CAS

North American Diatom Ecological Database (NADED)

NADED ID: 125011

Autecology Discussion

Habits

Size Range

11-100 µm3 (ie Achnanthidium)
101-1000 µm3 (ie Amphora veneta)

Motility

slightly motile (e.g. Cocconeis)

Attachment

prostrate (e.g. mucilage pad)

Habitat

benthic

Colony

solitary

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

Karayevia oblongella

Distribution

The distribution map represents the relative abundance of this Karayevia oblongella 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 Karayevia oblongella was not recorded, or with a red circle indicating the relative abundance of Karayevia oblongella.

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

Karayevia oblongella

Responses

The 15 response plots show an environmental variable (x axis) against the relative abundance (y axis) of Karayevia oblongella from all the stream reaches where it was present. Note that the relative abundance scale is the same on each plot. Explanation of each environmental variable and units are as follows:

ELEVATION = stream reach elevation (meters)
STRAHLER = distribution plot of the Strahler Stream Order
SLOPE = stream reach gradient (degrees)
W1_HALL = an index that is a measure of streamside (riparian) human activity that ranges from 0 - 10, with a value of 0 indicating of minimal disturbance to a value of 10 indicating severe disturbance.
PHSTVL = pH measured in a sealed syringe sample (pH units)
log_COND = log concentration of specific conductivity (µS/cm)
log_PTL = log concentration of total phosphorus (µg/L)
log_NO3 = log concentration of nitrate (µeq/L)
log_DOC = log concentration of dissolved organic carbon (mg/L)
log_SIO2 = log concentration of silicon (mg/L)
log_NA = log concentration of sodium (µeq/L)
log_HCO3 = log concentration of the bicarbonate ion (µeq/L)
EMBED = percent of the stream substrate that is embedded by sand and fine sediment
log_TURBIDITY = log of turbidity, a measure of cloudiness of water, in nephelometric turbidity units (NTU).
DISTOT = an index of total human disturbance in the watershed that ranges from 1 - 100, with a value of 0 indicating of minimal disturbance to a value of 100 indicating severe disturbance.

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.