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Due to the large size, this diatom has been confused with Gomphoneis herculeana. It differs in the shape of the valve, much more coarse density of the striae and the prominent spines at the headpole..

LM scalebar = 10 µm
Mammilla 001 Mammilla 003 Mammilla 005 Mammilla 002
Length Range
95-271 µm
Width Range
25-45 µm
Striae in 10 µm
7-9

Gomphoneis herculeana

(Ehrenb.) Cleve 1894

Herculeana 001 Herculeana 004B Herculeana 004A Herculeana 006 Herculeana 002 Herculeana 003 Herculeana 005
Length Range
50-165 µm
Width Range
22-34 µm
Striae in 10 µm
8-12 in the central valve, 12-14 at the headpole, 13-16 at the footpole