Caloneis tenuis has slightly larger valves and fascia-type central area. Caloneis arctica has larger valves and lower stria density. Species within Genkalia have a similar appearance of the axial and central area, particularly in smaller valves.

LM scalebar = 10 µm
Caloneis fusus LM1 Caloneis fusus LM2 Caloneis fusus LM3 Caloneis fusus LM4 Caloneis fusus LM5 Caloneis fusus LM6 Caloneis fusus LM7
Length Range
21-32 µm
Width Range
3.6-4.8 µm
Striae in 10 µm

Genkalia digitulus

(Hust.) Lange-Bert. and Kulikovskiy 2012

Genkalia Digitulus Me10023 A 101817 74 C Genkalia Digitulus Me10010 A 102417 02 C Genkalia Digitulus Me10009 C 101317 186 Genkalia Digitulus Nh10066 A 121117 11 C Genkalia Digitulus Me10023 A 101817 35 C Genkalia Digitulus Me10023 A 101817 31 C Genkalia Digitulus Cthp001 A 112117 68 C
Length Range
8.9-18.2 µm
Width Range
3.8-4.6 µm
Striae in 10 µm

Also compare to

Caloneis tenuis

BioData Reference
Krammer and Lange-Bertalot 2/1 Pl 174 Fig 5-10

Caloneis arctica

(Krasske) Lange-Bert.

Genkalia digituloides

(Lange-Bert.) Lange-Bert. and Kulikovskiy