Surirella cruciata has cuneate apices and does not twist about the apical axis. Surirella iowensis has porcae that are restricted to the margins. Surirella ovalis has smaller valves and distinct longitudinal markings running the length of the valve. Petrodictyon gemma has distinct costae rather than undulating ribs.

LM scalebar = 10 µm
Surirella striatula LM9 Surirella striatula LM3 Surirella striatula LM7 Surirella striatula LM4 Surirella striatula LM5 Surirella striatula LM8 Surirella striatula LM6
Length Range
70.7-126.5 µm
Width Range
46.4-80.7 µm
Striae in 10 µm

Surirella cruciata

A.Schmidt 1877

Gc 115390B  Sycamore Lnj  Sc27B  Do Us Copy Anp 058  Sur Cruc1C  Do Us2 Gc 113401A  Nantic R  De  Sc2B  Do Us Cas 183019  Lk Ozette  Wa  Sc8B Copy Hust X1 98  Sur Cruc Epitype1 C Publ Copy2 Boyer 375  Pavonia Nj  Sur Cruc4B Publ Copy
Length Range
48–160 µm
Width Range
24–61 µm
Striae in 10 µm
19–29 in the center valve, 22–30 at the ends

Surirella ovalis

Bréb. 1838

Gc109807B Ovalis 6 Gc106518B Ovalis 3 Gc109807B Ovalis 5 Gc109807B Ovalis 4 Gc106518B Ovalis 1 Gc109807B Ovalis 2 Gc109807B Ovalis 3
Length Range
14-75 µm
Width Range
11-35 µm
Striae in 10 µm

Surirella iowensis

R.L.Lowe 1973

Surirella iowensis LM7 Surirella iowensis LM6 Surirella iowensis LM4 Surirella iowensis LM2 Surirella iowensis LM3 Surirella iowensis LM1 Surirella iowensis LM5
Length Range
21-54 µm
Width Range
15-33 µm
Striae in 10 µm

Also compare to

Petrodictyon gemma

(Ehrenb.) D.G.Mann 1990