Compare Gomphonema caperatum
Gomphonema insularum is similar in length, breadth, and stria density but has a less linear, more lanceolate, even slightly clavate outline. Gomphonema insularum also has more uniformly short striae throughout the valve and round depressions on external valve surface.
Gomphonema incognitum is considerably more clavate. Gomphonema christenseni is both larger and lacks an isolated stigmoid.
Gomphonema freesei has a greater length and width.
LM scalebar = 10 µm
Length Range
22.4-31.9 µm
22.4-31.9 µm
Width Range
4.4-5.2 µm
4.4-5.2 µm
Striae in 10 µm
14-16
14-16
Length Range
17.8-29.5 µm
17.8-29.5 µm
Width Range
5.0-5.8 µm
5.0-5.8 µm
Striae in 10 µm
13-16 at mid-valve; up to 18 at the apices
13-16 at mid-valve; up to 18 at the apices
Length Range
15.2-42 µm
15.2-42 µm
Width Range
4.4-7 µm
4.4-7 µm
Striae in 10 µm
13-16
13-16
Length Range
32.8-57.4 µm
32.8-57.4 µm
Width Range
6.1-7.8 µm
6.1-7.8 µm
Striae in 10 µm
13-16
13-16
Length Range
35.0-53.9 µm
35.0-53.9 µm
Width Range
6.5-7.5 µm
6.5-7.5 µm
Striae in 10 µm
12.1-14.5 at valve center, 14.2-16.2 at headpole, 11.7-15.4 at footpole
12.1-14.5 at valve center, 14.2-16.2 at headpole, 11.7-15.4 at footpole
