Compare

Gomphonema caperatum and G. insularum are both less clavate. Gomphonema freesei is larger, both in length and breadth. Gomphonema amerhombicum is less clavate and larger in length and breadth. Gomphonema christenseni is larger and is astigmate.

LM scalebar = 10 µm
G Incog 15620A 10132015 12 Cl G Incog 15576A 08142015 20 Cl G Incog 15576A 08142015 37 Cl G Incog 15576A 08142015 21 Cl G Incog 15558A 08132015 42 Cl G Incog 15576A 08142015 29 Cl G Incognito Lm6
Length Range
17.8-29.5 µm
Width Range
5.0-5.8 µm
Striae in 10 µm
13-16 at mid-valve; up to 18 at the apices

Gomphonema insularum

Kociolek, Woodward and Graeff 2016

Gomphonema insularum LM1 Gomphonema insularum LM2 Gomphonema insularum LM3 Gomphonema insularum LM4 Gomphonema insularum LM5 Gomphonema insularum LM6 Gomphonema insularum LM7
Length Range
15.2-42 µm
Width Range
4.4-7 µm
Striae in 10 µm
13-16

Gomphonema freesei

R.L.Lowe and Kociolek 1984

Gc53921  Gomphonema Freesei 1 Gc53921  Gomphonema Freesei 2 Gc53921  Gomphonema Freesei 3 Gc53921  Gomphonema Freesei 4 Holotype Gc53921  Gomphonema Freesei 4B Holotype Gc53921  Gomphonema Freesei 5
Length Range
35.0-53.9 µm
Width Range
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

Gomphonema caperatum

Ponader and Potapova 2017

G Caperatum 15576A 08142015 08 Cl G Caperatum 15971A 04082016 01 G Caperatum 15577A 08172015 06 Cl G Caperatum 15558A 08132015 56 Cl G Caperatum 14368 12122016 02 Cl G Caperatum 15959A 04042016 33 Cl G Caperatum 15963A 04052016 02 Cl
Length Range
22.4-31.9 µm
Width Range
4.4-5.2 µm
Striae in 10 µm
14-16

Gomphonema christenseni

R.L.Lowe and Kociolek 1984

Gomphonema christenseni LM2 Gomphonema christenseni LM5 Gomphonema christenseni LM6 4 53920  Gchristenseni Holo 5 53920  Gchristenseni2 6 53920  Gchristenseni2 7 53920  Gchristenseni2
Length Range
32.8-57.4 µm
Width Range
6.1-7.8 µm
Striae in 10 µm
13-16

Also compare to

Gomphonema amerhombicum

E.Reichardt 2007