Valves are lanceolate with broadly rounded and unprotracted or very weakly protracted apices. A longitudinal line is evident along each margin. The axial area is straight, about three times wider than the raphe, becoming somewhat wider near the central area. The central area is wide, rectangular in shape and crosses the valve diagonally. It is bordered by short faint striae along the valve margins. The raphe is lateral, becoming filiform at the proximal ends, which are hooked sharply in opposite directions. Striae are oriented diagonally across the valve face. Areolae number 20-24 in 10 µm.
Besides three lakes in the Bob Marshall Wilderness of northwestern Montana, this taxon has been recorded from Logging Lake in nearby Glacier National Park. On the date the Logging Lake sample was collected, pH measured 7.78 and specific conductance measured 43. This species was also reported (as N. kozlowi var. elliptica) from a small pond in the Brooks Range of Alaska (Foged 1981).
Valves lanceolate with broadly rounded, very weakly protracted apices. Valve length 60–79 μm; valve width 14.8–17.8 μm. A longitudinal line evident along each margin. Axial area straight and narrow, flaring a bit near the central area. Central area wide, rectangular, oriented diagonally to the apical axis. Central area bordered by short faint striae along valve margins. Raphe lateral, becoming filiform at the proximal ends, which are hooked sharply in opposite directions. Striae oriented diagonally across the valve face, 13–15 in 10 μm. Areolae 20–24 in 10 μm.
From 9/29/2012 until 11/22/2024, this taxon appeared on this page as Neidium bobmarshallensis Bahls. The specific epithet ending is now corrected to reflect the Latin gender of the genus Neidium (neuter) as bobmarshallense. - S. Spaulding
Bahls, L. (2013). Neidium bobmarshallense. In Diatoms of North America. Retrieved December 26, 2024, from https://diatoms.org/species/48803/neidium_bobmarshallense
The 15 response plots show an environmental variable (x axis) against the relative abundance (y axis) of Neidium bobmarshallense 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.
Diatoms of North America is running a fundraising campaign to keep the servers in operation. We need you to reach our $25,000 fundraising goal.
If you use and appreciate DONA, make your DONAtion today.
For the Gift Designation, type "diatom" in the search box and select "Diatom Lab Research Fund". This is the designated fund for diatoms.org.