Compare

Pinnularia macilenta is wider than all varieties of P. subgibba.

Pinnularia subgibba var. undulata has a similar valve outline and distinct transverse fascia, although larger specimens are difficult to distinguish.

Pinnularia gibba has more capitate apices.

Pinnularia kittelii has wider valves and the central area is indistinct.

Pinnularia tabellaria is less broad, with a higher stria density and more capitate apices.

LM scalebar = 10 µm
Pinnularia macilenta LM6 Pinnularia macilenta LM1 Pinnularia macilenta LM3 Pinnularia macilenta LM4 Pinnularia macilenta LM5 Pinnularia macilenta LM2 Pinnularia macilenta LM7
Length Range
71-124 µm
Width Range
14-16.5 µm
Striae in 10 µm
7-9

Pinnularia subgibba

Krammer 1992

Pinnularia subgibba LM7 Pinnularia subgibba LM4 Pinnularia subgibba LM2 Pinnularia subgibba LM1 Pinnularia subgibba LM5 Pinnularia subgibba LM6 Pinnularia subgibba LM3
Length Range
63-127 µm
Width Range
11.7-13.6 µm
Striae in 10 µm
8-9

Pinnularia subgibba var. sublineairs

Krammer 2000

Pinnularia subgibba var. sublinearis LM1 Pinnularia subgibba var. sublinearis LM2 Pinnularia subgibba var. sublinearis LM4 Pinnularia subgibba var. sublinearis LM5 Pinnularia subgibba var. sublinearis LM3
Length Range
61-79 µm
Width Range
9-10 µm
Striae in 10 µm
9-10

Pinnularia lokana

Krammer 2000

Pinnularia lokana LM4 Pinnularia lokana LM7 Pinnularia lokana LM5 Pinnularia lokana LM6 Pinnularia lokana LM3 Pinnularia lokana LM1 Pinnularia lokana LM2
Length Range
78-118 µm
Width Range
12.4-14.7 µm
Striae in 10 µm
8-9

Pinnularia clericii

(Freng.) Freng. 1933

Pinnularia clericii LM5 Pinnularia clericii LM7 Pinnularia clericii LM1 Pinnularia clericii LM6 Pinnularia clericii LM4 Pinnularia clericii LM3 Pinnularia clericii LM2
Length Range
109-158 µm
Width Range
13.9-18.6 µm
Striae in 10 µm
7-9

Pinnularia subgibba var. undulata

Krammer 1992

Pinnularia subgibba var undulata LM6 Pinnularia subgibba var undulata LM3 Pinnularia subgibba var undulata LM4 Pinnularia subgibba var undulata LM5 Pinnularia subgibba var undulata LM2 Pinnularia subgibba var undulata LM1
Length Range
67-83 µm
Width Range
8.30-9.30 µm
Striae in 10 µm
9-10

Also compare to

Pinnularia gibba

BioData Reference
Krammer 2000 Pl 68 Fig 1-8 Pl 69 Fig 1-5

Pinnularia tabellaria

Ehrenb. 1843

Pinnularia kittelii

Krammer 2000