Navicula cryptocephala

Kützing 1844      Category: Symmetrical biraphid
BASIONYM: Navicula cryptocephala Kützing 1844

Navicula cincta

 

Navicula cryptocephaloides
Show images Hide

LM scalebar = 10 µm = 80 pixels.

Observations

Contributor: Marina Potapova - February 2011
Length Range: 21-34 µm
Width Range: 5.2-6.5 µm
Striae in 10 µm: 15-17

Description

Valves are lanceolate with protracted apices The axial area is narrow and straight. The central area is large and circular. The raphe is straight, with 'drop-like' expanded external proximal ends. Striae are radiate around the center, becoming convergent at the apices. The areolae are sometimes visible under LM, and number approximately 35 in 10 μm.

Original Description

Basionym: Navicula cryptocephala
Author: Kützing 1844
Length Range: 26.5-30 µm
Striae in 10 µm:

Original Description

N. minuta, laevissima, anguste lanceolata acuminate, apicibus globuloso-capitatis. Long. 1/75’’’-1/85’’’.

Original Images

Cite This Page:
Potapova, M. (2011). Navicula cryptocephala. In Diatoms of the United States. Retrieved May 19, 2013, from http://westerndiatoms.colorado.edu/taxa/species/navicula_cryptocephala

Species: Navicula cryptocephala

Contributor: Marina Potapova

Reviewer: Sarah Spaulding

Show guide Hide

Image Credit: Marina Potapova

  1. Valves lanceolate with protracted apices
  2. Central area large, circular
  3. External proximal raphe ends expanded

Valves are lanceolate with protracted apices The central area is large and circular. The raphe is straight, with 'drop-like' expanded external proximal ends. Striae are radiate around the center, becoming convergent at the apices. The areolae are sometimes visible under LM, approximately 35 in 10 μm.

Compare

Navicula cryptocephala differs from N. veneta by wider lanceolate valves with more protracted apices and by circular central area. Navicula trivialis has larger valves and lower stria density. Navicula notha has smaller central area and proximal raphe ends deflected to the primary side.

Navicula veneta

Navicula trivialis

Navicula notha

Citations

Cox, E.J. (1995). Taxonomic studies on the diatom genus Navicula Bory VII. The identity and typification of Navicula gregaria Donkin, N. cryptocephala Kutz. and related taxa. Diatom Research 10: 91-111.

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

Lange-Bertalot, H. (2001). Navicula sensu stricto, 10 genera separated from Navicula sensu lato, Frustulia. Diatoms of Europe 2: 1-526.

Links & ID's

Index Nominum Algarum (INA)

Original INA

California Academy of Sciences (CAS)

Navicula cryptocephala CAS

North American Diatom Ecological Database (NADED)

NADED ID: 46014

Autecology Discussion

Habits

Size Range

101-1000 µm3 (ie Amphora veneta)

Motility

moderately motile (e.g. Navicula tripunctata)

Attachment

unattached

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

Navicula cryptocephala

Distribution

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

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

Navicula cryptocephala

Responses

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