Diatoms of North AmericaDiatoms of North America
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Compare Gomphonema insularum

Kociolek, Woodward and Graeff 2016

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Gomphonema stoermeri has a more narrow axial area formed by the longer, more dense striae. Gomphonema caperatum is very similar, so much so that the two taxa may not be distinguished in the light microscope. The species are discernible in SEM, as G. caperatum has surficial wrinkles along the entire valve face, whereas G. insularum has a few centrally located shallow, rounded depressions. To date, the distribution of these taxa differ, with G. insularum known from the Hawaiian Islands, and G. caperatum found in continental North America.

LM scalebar = 10 µm
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 stoermeri

Kociolek and Kingston 1999

Gomphonema stoermeri LM7 Gomphonema stoermeri LM2 Gomphonema stoermeri LM3 Gomphonema stoermeri LM5 Gomphonema stoermeri LM1
Length Range
19-45 µm
Width Range
4-6 µm
Striae in 10 µm
13-15

Gomphonema caperatum

Ponader and Potapova 2017

Gomphonema caperatum LM3 Gomphonema caperatum LM7 Gomphonema caperatum LM4 Gomphonema caperatum LM2 Gomphonema caperatum LM1 Gomphonema caperatum LM5 Gomphonema caperatum LM6
Length Range
22.4-31.9 µm
Width Range
4.4-5.2 µm
Striae in 10 µm
14-16