Stauroneis phoenicenteron has smaller valves than S. rex (26-35 µm wide by 129-199 µm long) and a higher stria density (15-18 in 10 µm). It is likely that S. rex has been misidentified as S. phoenicenteron in U.S. surveys. Stauroneis terryi has septa and pseudosepta. Stauroneis baileyi, reported from Connecticut, has rhombic-lanceolate valves with narrower, more attenuated ends.

LM scalebar = 10 µm
Stauroneis rex LM6 Stauroneis rex LM2 Stauroneis rex LM5 Stauroneis rex LM1 Stauroneis rex LM3 Stauroneis rex LM7
Length Range
215-386 µm
Width Range
38-60 µm
Striae in 10 µm

Stauroneis phoenicenteron

(Nitzsch) Ehrenb. 1843

Stauroneis phoenicenteron LM5 Stauroneis phoenicenteron LM4 Stauroneis phoenicenteron LM3 Stauroneis phoenicenteron LM2 Stauroneis phoenicenteron LM1
Length Range
129-199 µm
Width Range
26-35 µm
Striae in 10 µm

Stauroneis terryi

D.B. Ward ex T.C. Palmer 1910

Stauroneis terryi LM6 Stauroneis terryi LM7 Stauroneis terryi LM2 Stauroneis terryi LM5 Stauroneis terryi LM4 Stauroneis terry LM1 Stauroneis terryi LM3
Length Range
154-388 µm
Width Range
35-58 µm
Striae in 10 µm

Also compare to

Stauroneis baileyi