Valves are elliptic-lanceolate to linear-lanceolate with protracted rostrate apices. The axial area is narrow and linear. The central area is asymmetric; it is barely differentiated from the axial area on one side of the valve, but enlarged on the other side. The raphe is filiform with enlarged proximal raphe ends that deflect toward one side of the valve. The distal fissures form a distinct hook on the mantle. The proximal and distal ends of the raphe are deflected to opposite sides of one another. Striae are lineolate, lineolae number about 20-25 in 10 µm. The striae are radiate at the center, to parallel or convergent at the apices. The space between the striae is wider or at least equal to the width of the striae. The central nodule is present on the same side as the deflected proximal fissures.
This taxon is characteristic of waters that are high in pH, conductance, and nutrients. It is a species that is tolerant of high sediment loads, turbidity, and other measures of human disturbance.
Valva linearis paulo lanceolata, ad apices attenuatae rostratae, 22 µ longa, 5µ lata, striis lineatis 15-17 per 10 µ, ad centrum valvae paulo radiatis, ad apices valvae parallelis vel plus minusve convergentibus; area axiali angusta; ad nodulum centralem paulo latiori. Pl.1, fig. 7. Distribution-Brazil: Rio Grande do Sul, current water at roadside, near the Lagua dos Quadros, 385 H. Kleerekoper July: 1941 (A-25741). Type (A-25741), scrapings from a stone only wetted at time of collecting, in a rapid near Lagua dos Quadros 367 H. Kleerekoper June 1941 (A-25734).
Manoylov, K., Hamilton, P. (2010). Navicula canalis. In Diatoms of North America. Retrieved November 23, 2024, from https://diatoms.org/species/navicula_canalis
The 15 response plots show an environmental variable (x axis) against the relative abundance (y axis) of Navicula canalis 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.