Compare Pinnularia ectorii
Pinnularia nobilis, P. nobilis var. regularis, P. roland-schmidtii, and P. pulchella var. canadensis have larger internal opening of alveoli, whose edges collectively appear in LM as a longitudinal line transecting the striae close to the central area.
Pinnularia roland-schmidtii, a species so far only known from South America, has a higher valve length/width ratio.
Pinnularia nobilis and P. nobilis var. regularis differ by more linear valves and a complex raphe.
Pinnularia pulchella var. canadensis is smaller and has large drop-shaped proximal raphe ends.
Pinnularia alabamae is larger and has capitate-cuneate apices and spines on the valve margin.
LM scalebar = 10 µm
Length Range
185–335 µm
185–335 µm
Width Range
29–44 µm
29–44 µm
Striae in 10 µm
5–6 throughout the valve, up to 9 around central area
5–6 throughout the valve, up to 9 around central area
Length Range
200-270 µm
200-270 µm
Width Range
32.5-39 µm
32.5-39 µm
Striae in 10 µm
5
5
Length Range
183-232 µm
183-232 µm
Width Range
29-34 µm
29-34 µm
Striae in 10 µm
6-7
6-7
Length Range
180-370 µm
180-370 µm
Width Range
32-48 µm
32-48 µm
Striae in 10 µm
5-6
5-6
