• Category
  • Length Range
    25-54 µm
  • Width Range
    7.3-9.7 µm
  • Striae in 10 µm
    13-14
  • Reported As
    Navicula ammophila (Witkowski, Lange-Bertalot, and Metzeltin 2000)

Identification

Description

Valves are lanceolate with narrow, weakly protracted and acutely pointed to obtusely rounded apices. The axial area is narrow and the central area is small and irregularly rounded. The raphe is filiform. Proximal raphe ends are small, close together and nearly straight. Terminal raphe fissures are bent toward the secondary side of the valve. Striae are weakly radiate in the middle and become weakly convergent near the valve ends. Areolae are distinct and number about 24 in 10 µm.

Autecology

There are 21 records of Navicula cryptocephaloides in the Montana Diatom Collection, all from streams in the Northwestern Great Plains Ecoregion of Montana, South Dakota, and Wyoming. Here it prefers warm, muddy, and brackish waters (mean conductivity = 18731 µS/cm). One of the MDC records is from Salt Creek, a small stream in northeastern Wyoming that is fed by salt springs. Here the conductivity measures 45700 µS/cm and chloride content is 13200 mg/L. Common diatom associates of Navicula cryptocephaloides in Salt Creek are Mastogloia pumila, Haslea spicula, and Nitzschia pararostrata. This taxon was described from salt springs in Java.

Img 2208
Credit: Photo courtesy Wyoming DEQ
Salt Creek, Weston County, Wyoming: home of Navicula cryptocephaloides.

Original Description

Schalen linear-lanzettlich mit wenig konvexen bis fast parallelen Seiten und leicht geschnabelten, nicht kopfigen Enden, 30-40 microns lang, 7-9 microns breit. Raphe gerade, Axialarea eng, Zentralarea quer verbreitert, unregelmassig begrenzt. Transapikalstreifen im mittleren Teil wenig radial, an den polen schwach konvergent, 14 in 10 microns, deutlich liniiert, Linien 28-30 in 10 microns. Taf. XVIII, Fig. 1, 2.

  • Author
    Hust. 1937
  • Length Range
    30-40 µm
  • Width
    7-9 µm
  • Striae in 10µm
    14

Original Images

Ncryptocephaloides Origimag
Navcryptocephaloides  Hustedt1
Navcryptocephaloides  Hustedt2
Ncryptocephaloides Origdesc

Cite This Page

Bahls, L. (2011). Navicula cryptocephaloides. In Diatoms of North America. Retrieved June 19, 2018, from https://diatoms.org/species/navicula_cryptocephaloides

Responses

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