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Gomphoneis eriense var. variabilis is distinguished from other taxa considered within the basionym for this taxon. It differs from G. eriense var. angularis and G. eriense var. rostrata in that the valves are more rounded and have the broadest portion of the valve at the center. Gomphoneis eriense var. variabilis is distinguished from G. subherculeana by being narrower, and having finer striae. Gomphoneis eriense var. variabilis is distinguished from G. septa by smaller valves that are more broadly rounded.

This species has been confused with taxa in Gomphonema, specifically G. ventricosum and G. manubrium. Unlike those species, Gomphoneis eriense var. variabilis has longitudinal lines and striae composed of doubly-punctate striae.

LM scalebar = 10 µm
Gomphoneis eriense var variabilis LM3 Gomphoneis eriense var variabilis LM5 Gomphoneis eriense var variabilis LM2 Gomphoneis eriense var variabilis LM1 Gomphoneis eriense var variabilis LM4
Length Range
25-45 µm
Width Range
9.5-12 µm
Striae in 10 µm
10-13 in the center, 14-16 at the poles

Gomphoneis eriense var. angularis

Kociolek and Stoermer 1988

Gomphoneis eriense var. angularis LM1 Gomphoneis eriense var. angularis LM4 Gomphoneis eriense var. angularis LM5 Gomphoneis eriense var. angularis LM2 Gomphoneis eriense var. angularis LM3
Length Range
34-67 µm
Width Range
8-12 µm
Striae in 10 µm
10-13 at the central portion, 14-16 at the poles

Gomphoneis septa

(Moghadam) Kociolek, Stoermer and L.L.Bahls 1986

Gomphoneis septa LM3 Gomphoneis septa LM4 Gomphoneis septa LM5 Gomphoneis septa LM2 Gomphoneis septa LM1
Length Range
34-90 µm
Width Range
11-15 µm
Striae in 10 µm
11-12 at the center, 14-16 at the poles

Also compare to

Gomphoneis rostrata

(Temp. and H.Perag.) Kociolek and Stoermer

Gomphoneis subherculeana

Kociolek and Stoermer

Gomphonema manubrium

Fricke