Compare Rhoicosphenia californica
Narrow valves with protracted apices distinguish R. californica from R. abbreviata, which is wider and has bluntly rounded apices. The striae of R. abbreviata are lineate on both valves. In contrast, the striae of R. californica are lineate, except they are often punctate bordering the axial area. Rhoicosphenia californica is smaller than R. stoermeri. The striae of R. stoermeri are distinctly punctate.
LM scalebar = 10 µm
Length Range
8-50 µm
8-50 µm
Width Range
3-6 µm
3-6 µm
Striae in 10 µm
11-12 in the center valve, 13-15 at the ends
11-12 in the center valve, 13-15 at the ends
Length Range
10–55 µm
10–55 µm
Width Range
4–8 µm
4–8 µm
Striae in 10 µm
15-20
15-20
Length Range
25-84 µm
25-84 µm
Width Range
6-9 µm
6-9 µm
Striae in 10 µm
11-13 in the center valve, 14-16 at the ends
11-13 in the center valve, 14-16 at the ends
