Guide to Nupela scissura
Credit: Paul Hamilton, Marina Potapova
- Valves broadly elliptical-lanceolate
- Frustules heterovalvar
- Striae not discernable in LM
- Central area of raphe valve asymmetric and rectangular to wedge shaped
- Central area of rapheless valve asymmetric and broadly wedge shaped
Valves are broadly elliptical-lanceolate with apiculate apices, 9 – 15 μm long, 4.5 – 5.0 μm wide. Frustules are heterovalvar, each frustule with a raphe and rapheless valve. Striae are slightly radiate to parallel on the raphe valve and more radiate on the rapheless valve. Striae are 48 – 58 in 10 µm, so that they are not visible in LM. The central areas of both valves are asymmetric and wedge shaped. The central area of the raphe valve is nearly rectangular, while the central area of the rapheless valve is more broad.