Guide to Surirella brebissonii
Credit: Jonathan English, Marina Potapova
- Keel low, alar wings absent
- Valves large, heteropolar
- Valves with large size range
- Fibula density 5-6 in 10 µm
- Costa density 18-23 in 10 µm
Valves with large size range, 15.5-56.0 µm in length and 10-25 µm in width. Smaller valves are almost circular, but larger valves have one broadly rounded apex and one cuneately rounded apex. Costa density is 18-23 in 10 µm and fibula density is 5-6 in 10 µm.