Psammothidium marginulatum

(Grunow) Bukhtiyarova and Round 199      Category: Monoraphid
BASIONYM: Achnanthes marginulata Grunow in Cleve and Grunow 1880

Psammothidium levanderi

 

Psammothidium pennsylvanicum
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LM scalebar = 10 µm = 80 pixels.

Observations

Contributor: Marina Potapova - August 2010
Length Range: 8-16 µm
Width Range: 4.4-5.8 µm
Striae in 10 µm: 23-27

Description

Valves are elliptical-lanceolate to linear-elliptical. The raphe valve has a linear axial area, which widens toward the center of the valve, and a transversely elliptical central area. The raphe is straight, without terminal fissures. The central and terminal raphe ends are simple. The central raphe ends curve toward opposite sides internally. The rapheless valve has a wide rhomboid-lanceolate axial area. The central area is usually not differentiated from the axial area. Striae are radiate on both valves, 23-27 in 10 µm. One row of areolae is present on the mantle of both valves. The external openings of the areolae are small , circular.

Original Description

Basionym: Achnanthes marginulata
Author: Grunow in Cleve and Grunow 1880
Length Range: 11-14 µm
Width Range: 5 µm
Striae in 10 µm:

Original Description

Sehr klein, wenig gebogen. Schaalen oval oder fast stumpf lanzettlich. Die Querstreifen der Oberschaale kurz, randständig, die der Unterschaale radial, die Mittellinie erreichend, in der Mitte beim breiten Pseudostauros aber nur sehr kurz, randständig, 24-25 in 0,01 mm. Länge 0,011-0,014 mm., Breite 0,005 mm. Memerutungen. (Norwegen.) O. Nordstedt

Original Images

Cite This Page:
Potapova, M. (2010). Psammothidium marginulatum. In Diatoms of the United States. Retrieved July 25, 2014, from http://westerndiatoms.colorado.edu/taxa/species/psammothidium_marginulatum

Species: Psammothidium marginulatum

Contributor: Marina Potapova

Reviewer: Sarah Spaulding

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Image Credit: Marina Potapova

  1. Valves elliptical-lanceolate to linear-elliptical
  2. Raphe valve with transversely elliptical central area
  3. Rapheless valve with wide rhomboid-lanceolate axial area

Valves are elliptical-lanceolate to linear-elliptical. The raphe valve has a linear axial area, which widens toward the center of the valve, and a transversely elliptical central area. The raphe is straight, without terminal fissures. The rapheless valve has a wide rhomboid-lanceolate axial area. Striae are radiate on both valves, 23-27 in 10 µm.

Compare

Psammothidium marginulatum differs from P. scoticum by its wider axial area on rapheless valve, elliptical-lanceolate valve shape, and lower striae density. Psammothidium scoticum differs from P. daonense and P. ventralis by its linear-elliptical shape. Valves of P. altaicum are rhomboid-lanceolate with higher striae density.

Psammothidium scoticum

Citations

Bukhtiyarova, L. and Round, F. E. (1996). Revision of the genus Achnanthes sensu lato. Psammothidium, a new genus based on Achnanthidium marginulatum. Diatom Research 11: 1-30.

Cleve, P.T. and Grunow, A. (1880). Beiträge zur Kenntniss der Arctischen Diatomeen. Kongliga Svenska-Vetenskaps Akademiens Handlingar, Vol: 17, Issue: 2, 121 pp., 7 pls.

Links & ID's

Index Nominum Algarum (INA)

Original INA

California Academy of Sciences (CAS)

Psammothidium marginulatum CAS

North American Diatom Ecological Database (NADED)

NADED ID: 186005

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

Psammothidium marginulatum

Distribution

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

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

Psammothidium marginulatum

Responses

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