Gomphoneis pseudokunoi, G. quadripunctata, Gomphonema olivaceoides var. densestriata and Gomphonema olivaceoides var. hutchinsoniana all have stigmoids in the central area. Gomphosinica geitleri has a single stigmoid.

LM scalebar = 10 µm
Gomphoneis olivaceum LM1 Gomphoneis olivaceum LM5 Gomphoneis olivaceum LM3 Gomphoneis olivaceum LM6 Gomphoneis olivaceum LM7 Gomphoneis olivaceum LM2 Gomphoneis olivaceum LM4
Length Range
14-40 µm
Width Range
5-8 µm
Striae in 10 µm
10-13 in the center of the valve, 12-14 at the ends

Gomphonella pseudookunoi

(Tuji) Tuji 2020

Gomphoneis pseudo-okunoi LM7 Gomphoneis pseudo-okunoi LM6 Gomphoneis pseudo-okunoi LM3 Gomphoneis pseudo-okunoi LM2 Gomphoneis pseudo-okunoi LM5 Gomphoneis pseudo-okunoi LM4 Gomphoneis pseudo-okunoi LM1
Length Range
11-30 µm
Width Range
4-7 µm
Striae in 10 µm

Gomphonella fogedii

Edlund 2024

Gomphonema olivaceoides var densestriata LM1 Gomphonema olivaceoides var. densestriata LM2 Gomphonema olivaceoides var. densestriata LM3 Gomphonema olivaceoides var. densestriata LM5 Gomphonema olivaceoides var. densestriata LM6 Gomphonema olivaceoides var. densestriata LM4 Gomphonema olivaceoides var. densestriata LM7
Length Range
15-33 µm
Width Range
5.1-6.2 µm
Striae in 10 µm

Gomphonella hutchinsoniana

(R.M.Patrick) Tuji 2020

Gomphonema Olivaceoides Hutchinsoniana 17 668Px  Gc112789 Gomphonema Olivaceoides Hutchinsoniana 642Px F  Gc112789A Gomphonema Olivaceoides Hutchinsoniana 627Px 15  Gc112789 Gomphonema Olivaceoides Hutchinsoniana 622Px 19  Gc112789A Gomphonema Olivaceoides Hutchinsoniana 623Px B  Gc112789A Gomphonema Olivaceoides Hutchinsoniana 595Px 11  Gc112789 Gomphonema Olivaceoides Hutchinsoniana 551Px 16  Gc112789
Length Range
18.4-23.4 µm
Width Range
5.5-6.1 µm
Striae in 10 µm

Gomphosinica geitleri

(Kociolek and Stoermer) Kociolek et al. 2015

G Geitleri 6 G Geitleri 5 Copy Gomphosinica geitleri LM1 Gomphosinica geitleri LM3 Gomphosinica geitleri LM2 Gomphosinica geitleri LM5 Gomphosinica geitleri LM4
Length Range
12-38 µm
Width Range
4.5-6.6 µm
Striae in 10 µm
16-20 near the center valve, 18-20 near the headpole, 16-20 near the footpole

Also compare to

Gomphonella olivaceoides

(Hust.) Tuji

Gomphoneis quadripunctata

(Østrup) P.A.Dawson ex R.Ross and P.A.Sims