Diatoms of North AmericaDiatoms of North America
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Compare Surirella ovalis

Bréb. 1838

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Surirella. ovalis is distinguished from the other low-keeled species of Surirella by greater width, lower fibula and costa density and rounded valve outline. Only the larger valves of S. ovalis are distinguishable from S. brebissonii. The larger valves of S. brebissonii have one broadly rounded apex and one cuneately rounded apex, while S. ovalis has two cuneately rounded apices. The smaller valves of the two species, however, are virtually indistinguishable. The only difference between them is the number of portulae, a feature visible in SEM. Surirella ovalis has one portula between each fibula, while S. brebissonii has 3 to 4 portulae between each fibula.

LM scalebar = 10 µm
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
14-17

Surirella brebissonii

Krammer and Lange-Bert. 1987

Gc112761A Brebissonii 9 Gc112761A Brebissonii 10 Gc112761A Brebissonii 4 Gc112761A Brebissonii 3 Gc112761A Brebissonii 8 Gc109819B Brebissonii 3 Gc112761A Brebissonii 7
Length Range
15.5-56 µm
Width Range
10-25 µm
Striae in 10 µm
18-23

Surirella pinnata

W.Smith 1853

Surirella minuta LM1 Surirella minuta LM5 Surirella minuta LM2 Surirella minuta LM3 Surirella minuta LM6 Surirella minuta LM4 Surirella minuta LM7
Length Range
18-71 µm
Width Range
8.5-14 µm
Striae in 10 µm
25-32

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
16-26