Planothidium delicatulum

(Kützing) Round and Bukhtiyarova 1996      Category: Monoraphid
BASIONYM: Achnanthidium delicatulum Kützing 1844

REPORTED AS: Achnanthes delicatula  (Cleve and Grunow 1880) 

Planothidium calcar

 

Planothidium dubium
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LM scalebar = 10 µm = 80 pixels.

Observations

Contributor: Marina Potapova - December 2010
Length Range: 12-20 µm
Width Range: 4.7-7.5 µm
Striae in 10 µm: 13-15

Description

Valves are lanceolate with protracted subrostrate apices The raphe valve has a transversely elliptical or rectangular central area. The rapheless valve has a linear-lanceolate axial area. The features of the middle of the rapheless valve are variable across populations: valves may lack a distinguishable central area, or two middle striae on one side of the axial area can be slightly more distant from one another than from the other striae. The raphe is straight with expanded external proximal ends. The striae are strongly radiate on the raphe valve and slightly radiate on the rapheless valve.

Note that this concept of P. delicatulum more or less corresponds to the “Sippen mit schnabelartig vorgezogenen Polen” in Krammer & Lange-Bertalot (1991, figs 39:6-14), while the Neotype of Achnanthes delicatula may represent a similar, but different species (Figs 39: 1-5 in Krammer & Lange-Bertalot 1991). Further work is needed to clarify taxonomy of this species complex.

Original Description

Basionym: Achnanthidium delicatulum
Author: Kützing 1844
Length Range: 16 µm
Striae in 10 µm:

Original Description

A. a latere secundario ven-tricosum, apicibus productis.

Original Images

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

Species: Planothidium delicatulum

Contributor: Marina Potapova

Reviewer: Sarah Spaulding

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Image Credit: Marina Potapova

  1. Apices protracted and subrostrate
  2. Raphe valve with transversely elliptical or rectangular central area
  3. Rapheless valve lacks a central area
  4. Rapheless valve may have 2 middle, distant striae on one valve side

Valves are lanceolate with protracted subrostrate apices. The raphe valve has a transversely elliptical or rectangular central area. The rapheless valve has a linear-lanceolate axial area and no distinguishable central area, or two middle striae on one side of the raphe can be slightly more distant for each other than from the other striae.

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The raphe valves may be mistaken for those of P. apiculatum. The rapheless valves of P. apiculatum, however, possess a hood – a feature not found in P. delicatulum.

Planothidium apiculatum

Citations

Kützing, F.T. (1844). Die kieselschaligen Bacillarien oder Diatomeen. Nordhausen. 152 pp., 30 pls.

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)

Planothidium delicatulum CAS

North American Diatom Ecological Database (NADED)

NADED ID: 155009

Autecology Discussion

Habits

Size Range

101-1000 µm3 (ie Amphora veneta)

Motility

slightly motile (e.g. Cocconeis)

Attachment

unattached

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

Planothidium delicatulum

Distribution

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

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

Planothidium delicatulum

Responses

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