Achnanthidium kranzii

(Lange-Bertalot) Round & Bukhtiyarova 1996      Category: Monoraphid
BASIONYM: Achnanthes kranzii Lange-Bertalot in Lange-Bertalot & Krammer 1989

Achnanthidium gracillimum

 

Achnanthidium kriegeri
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LM scalebar = 10 µm = 80 pixels.

Observations

Contributor: Marina Potapova - March 2011
Length Range: 8-20 µm
Width Range: 2.8-3.8 µm
Striae in 10 µm: 24-30 in the center valve, up to 40 at the ends

Description

Frustules are monoraphid with a concave raphe valve and a convex rapheless valve. Valves are linear-lanceolate to linear-elliptical with slightly drawn-out ends. The raphe valve has a large rectangular central area that often extends to valve margins. The rapheless valve has an apically elongated elliptical or rhomboid central area. Proximal external raphe endings are simple. Terminal raphe fissures are short and sharply curved to the same side. Striae are moderately radiate in the center of both valves, becoming parallel at the apices, 24-30 in 10 µm in the central valve, up to 40 in 10 µm at the apices. Striae are uniseriate. One row of areolae is present on the valve mantle, visible in SEM. External areolae openings of areolae are very small and vary in shape from circular to transapically elongated.

Original Description

Basionym: Achnanthes kranzii
Author: Lange-Bertalot in Lange-Bertalot & Krammer 1989
Length Range: 6-20 µm
Width Range: 3.5-4 µm
Striae in 10 µm: 25-30 in the center valve, 35-40 at the ends

Original Description

Valvae ellipticae, lineari-ellipticae ad elliptico-lanceolatae apicibus obtuse vel late rotundatis, 6-20 µm longae, 3.5-4 µm latae. Raphovalva: Rami raphis filiformes, recto ex poris centralibus modice approximatis, ad apicibus versus, prope marginem limbi curvati in eandem directionem. Area axialis anguste linearis ad lineari-lanceolata. Area centralis plus minusque amplam fasciam formans pro parte margines attingens. Areovalva: areae centralis rhombice transirens in aream axialis anguste linearis. Striae transapicales modice radiantes in medio at amplior positae, circiter 25-30/10 µm, sub apices parallelae vel paulo convergentes et densior positae, circiter 35-40/10 µm. A speciebus similibus satis differt combinatione pljurium qualitatium.

Original Images

Cite This Page:
Potapova, M. (2011). Achnanthidium kranzii . In Diatoms of the United States. Retrieved May 23, 2017, from http://westerndiatoms.colorado.edu/taxa/species/achnanthidium_kranzii

Species: Achnanthidium kranzii

Contributor: Marina Potapova

Reviewer: Sarah Spaulding

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Image Credit: Marina Potapova

  1. Valves linear-lanceolate to linear-elliptical
  2. Striae radiate in the center, parallel at the ends
  3. Raphe valve with large rectangular central area
  4. Rapheless valve with apically elliptical or rhomboid central area
  5. Terminal raphe fissures curved to one side

Valves are linear-lanceolate to linear-elliptical with slightly drawn-out ends, 2.8-3.8 µm wide, 8-18 µm long. The raphe valve has a large rectangular central area that often extends to valve margins. The rapheless valve has an apically elongated elliptical or rhomboid central area. Terminal raphe fissures are sharply curved to the same side. Striae are uniseriate, moderately radiate in the middle part of both valves, becoming parallel at the apices, 24-30 in 10 µm in the central valve, up to 40 in 10 µm at the apices.

Compare

Achnanthidium kranzii is similar to A. minutissimum in valve shape and size, but can be distinguished from A. minutissimum by the curved terminal raphe fissures that are usually visible in LM. In addition, A. kranzii has wider valves (on average), a large rectangular central area on the raphe valve and a distinct rhomboid, or apically elliptical, central area on the rapheless valve.

Achnanthidium minutissimum

Citations

Lange-Bertalot, H. and Krammer, K. (1989). Achnanthes eine Monographie der Gattung mit Definition der Gattung Cocconeis and Nachtragen zu den Naviculaceae. Bibliotheca Diatomologica 18, 393 pp. Cramer, Berlin, Stuttgart.

Round, F. E. and Bukhtiyarova, L. (1996). Four new genera based on Achnanthes (Achnanthidium) together with a re-definition of Achnanthidium. Diatom Research 11: 345-361.

Links & ID's

Index Nominum Algarum (INA)

Original INA

California Academy of Sciences (CAS)

Achnanthidium kranzii CAS

North American Diatom Ecological Database (NADED)

NADED ID: 1027

Autecology Discussion

Habits

Size Range

11-100 µm3 (ie Achnanthidium)

Motility

slightly motile (e.g. Cocconeis)

Attachment

prostrate (e.g. mucilage pad)

Habitat

benthic

Colony

solitary

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

Achnanthidium kranzii

Distribution

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

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

Achnanthidium kranzii

Responses

The 15 response plots show an environmental variable (x axis) against the relative abundance (y axis) of Achnanthidium kranzii 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.